US20110128654A1 - Short circuit current ratcheting in switch mode dc/dc voltage regulators - Google Patents

Short circuit current ratcheting in switch mode dc/dc voltage regulators Download PDF

Info

Publication number
US20110128654A1
US20110128654A1 US13/016,818 US201113016818A US2011128654A1 US 20110128654 A1 US20110128654 A1 US 20110128654A1 US 201113016818 A US201113016818 A US 201113016818A US 2011128654 A1 US2011128654 A1 US 2011128654A1
Authority
US
United States
Prior art keywords
side pass
pass device
coupled
comparator
current
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Abandoned
Application number
US13/016,818
Inventor
Andrew Wu
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Individual
Original Assignee
Individual
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Family has litigation
First worldwide family litigation filed litigation Critical https://patents.darts-ip.com/?family=36788458&utm_source=google_patent&utm_medium=platform_link&utm_campaign=public_patent_search&patent=US20110128654(A1) "Global patent litigation dataset” by Darts-ip is licensed under a Creative Commons Attribution 4.0 International License.
Application filed by Individual filed Critical Individual
Priority to US13/016,818 priority Critical patent/US20110128654A1/en
Publication of US20110128654A1 publication Critical patent/US20110128654A1/en
Abandoned legal-status Critical Current

Links

Images

Classifications

    • HELECTRICITY
    • H02GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02MAPPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M3/00Conversion of dc power input into dc power output
    • H02M3/02Conversion of dc power input into dc power output without intermediate conversion into ac
    • H02M3/04Conversion of dc power input into dc power output without intermediate conversion into ac by static converters
    • H02M3/10Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H02M3/145Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
    • H02M3/155Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only
    • H02M3/156Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of output voltage or current, e.g. switching regulators
    • H02M3/158Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of output voltage or current, e.g. switching regulators including plural semiconductor devices as final control devices for a single load
    • H02M3/1588Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of output voltage or current, e.g. switching regulators including plural semiconductor devices as final control devices for a single load comprising at least one synchronous rectifier element
    • HELECTRICITY
    • H02GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02MAPPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M1/00Details of apparatus for conversion
    • H02M1/32Means for protecting converters other than automatic disconnection
    • HELECTRICITY
    • H02GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02MAPPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M1/00Details of apparatus for conversion
    • H02M1/0003Details of control, feedback or regulation circuits
    • H02M1/0009Devices or circuits for detecting current in a converter
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02BCLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
    • Y02B70/00Technologies for an efficient end-user side electric power management and consumption
    • Y02B70/10Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes

Definitions

  • a DC/DC voltage regulator is operative to maintain a level output voltage despite variations in power supply voltage or current drawn by a load.
  • Many portable devices require a steady voltage supply such as that provided by a DC/DC voltage regulator.
  • Switch mode regulators can be subject to a phenomenon of current ratcheting at shorted loads due to finite on times to determine an over current condition. Nearly every switch-mode device has a finite loop response time to measure current in the inductor. Depending on the input voltage, the current can rise high enough to cause a catastrophic failure in a device.
  • frequency fold-back to change the amount of current ratcheting that a part can see.
  • a common problem caused by frequency fold-back is a large current ripple in the inductor. For this reason, a larger than normal bypass or output capacitor is chosen to reduce the ripple voltage. And if the frequency is folded back too much, the loop may become unstable. Thus, choosing the correct fold-back frequency range for wide application is not an easy task.
  • a DC/DC switch mode voltage regulator with a high side pass device and a low side pass device.
  • the voltage regulator includes means for detecting an over current condition over a current limit on the high side pass.
  • the voltage regulator also includes means for locking out the high side pass device and turning on the low side pass device until a second current limit located on the low side pass device is reached if the over current condition is detected.
  • a method implemented on a DC/DC switch mode voltage regulator with a high side pass device and a low side pass device includes detecting an over current condition over a current limit on the high side pass. The method also includes locking out the high side pass device and turning on the low side pass device until a second current limit located on the low side pass device is reached if the over current condition is detected.
  • an apparatus in still another embodiment, includes a high side pass device.
  • the apparatus also includes a low side pass device coupled in series to the high side pass device.
  • the apparatus further includes a control module coupled to the high side pass device and the low side pass device.
  • the control module is coupled to the high side pass device and the low side pass device to control the high side pass device and the low side pass device.
  • the apparatus includes a first resistor coupled in series with the high side pass device and the low side pass device. Furthermore, the apparatus includes a first comparator coupled in parallel with the first resistor. The first comparator has a threshold voltage input differential corresponding to a first current limit, and an output of the first comparator is coupled to the control module. Moreover, the apparatus includes a second comparator coupled to sense current of the high side pass device as a voltage. The second comparator has a threshold voltage input differential corresponding to a second current limit. An output of the second comparator is coupled to the control module. The second current limit is higher than the first current limit. Also, the control module is operable to lock out the high side pass device responsive to the output of the first comparator until a reset signal is received and is operable to lock out the high side pass device responsive to the output of the second comparator until a low current signal is received.
  • FIG. 1 illustrates an embodiment of a DC-DC voltage regulator output.
  • FIG. 2 illustrates current overload in the embodiment of FIG. 1 .
  • FIG. 3 illustrates frequency folding in the embodiment of FIG. 1 .
  • FIG. 4 illustrates an embodiment of a current overload protection apparatus for the DC-DC voltage regulator output of FIG. 1 .
  • FIG. 5 illustrates an alternate embodiment of the current overload protection apparatus for the DC-DC voltage regulator output of FIG. 1 .
  • FIG. 6 illustrates current ratcheting in the embodiment of FIG. 4 .
  • FIG. 7 illustrates another alternate embodiment of the current overload protection apparatus for the DC-DC voltage regulator output of FIG. 1 .
  • FIG. 8 illustrates an embodiment of a process of current limiting.
  • a system, method and apparatus is provided for Short Circuit Current Ratcheting in Switch Mode DC/DC Voltage Regulators.
  • the specific embodiments described in this document represent exemplary instances of the present invention, and are illustrative in nature rather than restrictive.
  • the present invention describes, in some embodiments, a new scheme that eliminates frequency fold-back from the protection scheme of switch-mode regulators and allows for a clean startup without the need for a change in switching frequency for the entire duration of operation.
  • a sense element is used to measure the current in the inductor.
  • a comparator is used to compare the sense element to another matching element that depicts a finite known current threshold indicating the overcurrent conditions. When this current threshold is exceeded, the comparator signals the logic to latch the low side switch on until a low side current limit is reached.
  • This current limit on the low side can be set to any value positive, negative, or zero inductor current depending on the application.
  • a DC/DC switching voltage regulator in some embodiments, consists of a PWM controller, two controlled pass devices that are connected in series between a supply voltage and ground, an inductor that is connected to the common point between the two pass devices, and a capacitor connected between the output node and ground after the inductor.
  • the inductor By modulating the pass devices, the inductor will build up energy and discharge it into the capacitor.
  • the charge and discharge rates are governed by the equation:
  • V L ⁇ ⁇ I ⁇ T
  • Rondwn is the resistance in the lower pass device.
  • FIG. 1 illustrates an embodiment of a DC-DC voltage regulator output.
  • System 100 includes high and low supply transistors between a power rail and ground, an inductive load and a capacitor.
  • Inductive load 110 may be an actual inductor or a component which operates in a manner similar to an inductor.
  • Capacitor 160 is coupled between inductive load 110 and ground 150 . Power is supplied to load 110 through power transistor 120 (current is sourced) from power supply 130 . Current may be sunk from inductive load 110 through power transistor 140 to ground 150 .
  • FIG. 2 illustrates current overload in the embodiment of FIG. 1 .
  • Current levels approach a limit value, and the system reduces the current level.
  • the decay time for the current may not allow the current level to drop to zero.
  • the device may then increase the current level again, this time overshooting the maximum current limit before the system reduces current again. This typically happens as a result of the frequency at which the system operates—it may reset the voltage regulator before the current decays to an acceptable level.
  • FIG. 3 illustrates frequency folding in the embodiment of FIG. 1 .
  • the current is allowed to decay over a longer time until an acceptable limit is reached. Not shown is the lead-up to this situation, where the device may run to the limit, and then be reduced to a level too high to avoid an overcurrent situation. Frequency folding can avoid the overcurrent situation, but it also slows down operation of the system and the load to which power is supplied.
  • FIG. 4 illustrates an embodiment of a current overload protection apparatus for the DC-DC voltage regulator output of FIG. 1 .
  • System 400 includes device 410 (a DC-DC voltage regulator) various exterior circuitry which may be supplied as part of an overall system.
  • Device 410 may be enabled by enable input 493 , which is tied to internal enable circuitry 490 .
  • Power may be supplied from a power supply which is modeled as capacitor 433 .
  • resistor 450 Current into the load 110 through power transistor 120 is monitored passing that current through resistor 450 which is sensed in current sense amplifier 455 (an amplifier which level-shifts the voltage across its inputs and amplifies that voltage).
  • the output of comparator 450 is mixed with the output of an oscillator 485 and provided as input to comparator 480 .
  • comparator 480 and control module 415 this provides the feedback loop for the pulse width modulator of device 410 .
  • Resistors 460 and 465 provide a resistive divider from which a voltage level is drawn for feedback component 470 .
  • resistor 483 and capacitor 487 provide an RC component which controls the output of comparator 475 .
  • Comparator 435 senses current from resistor 440 , which is coupled in series with power transistor 140 , and provide a set input to flip-flop 445 .
  • Comparator 430 senses current through resistor 440 and power transistor 140 (the same current) and provides a reset input to flip-flop 445 .
  • These outputs are also provided to control logic 415 .
  • control logic 415 operates gates 420 and 425 to turn power transistors 120 and 140 on and off.
  • the output of flip-flop 445 causes transistor 140 to turn on and transistor 120 to turn off. Once current through transistor 140 has decayed sufficiently, flip-flop 445 is reset, and normal operation returns.
  • various current levels for overlimit and low current can be set.
  • FIG. 5 illustrates an alternate embodiment of the current overload protection apparatus for the DC-DC voltage regulator output of FIG. 1 .
  • System 500 operates the power supply to load 110 .
  • Resistive divider 570 and 575 provides a voltage which is fed back and compared with a reference voltage at comparator 560 .
  • the output of comparator 560 is biased with transistor 565 , which receives a Vilimit voltage input to determine the bias level.
  • Schmitt-triggered buffer 555 then provides the biased output of comparator 560 as a logic input to flip-flop 530 .
  • Flip-flop 520 then controls transistors 120 and 140 (through inverter 525 ).
  • buffer 555 may be an error amplifier similar to amplifier 475 of FIG. 4 , which would then be integrated into the PWM feedback loop of the over all system.
  • the PWM feedback loop and other details are not illustrated to avoid obscuring details of the embodiment.
  • Comparator 540 also receives as input the output of transistor 550 , which is biased by a voltage Vilimit+X. Current source 545 completes the bias circuitry of this component.
  • comparator 540 can set (or reset) the flip-flop 520 . This allows for turning off supply of current to load 110 .
  • comparator 530 may reset (or set) flip-flop 520 , allowing normal operation to continue.
  • Vilimit and Vilimit+X may be chosen as appropriate in various embodiments. Typically, Vilimit+X will be a higher value than Vilimit, and will provide a higher current limit as a limit which can be used to shut down the system and avoid a current overload.
  • FIG. 6 illustrates current ratcheting in the embodiment of FIG. 4 .
  • Current may rise to Ilimit, and then be ratcheted back down. If the device is operating at too high a frequency, then the current can increase to Ilimit+X. At this point, the device can be shut down (by turning off the high pass transistor 120 and turning on the low pass transistor 140 ) until the current decays to an acceptable level (as may be defined by a low current value).
  • FIG. 7 illustrates another alternate embodiment of the current overload protection apparatus for the DC-DC voltage regulator output of FIG. 1 .
  • System 700 includes a power supply, control logic, load, and current monitor.
  • Power supply module 710 supplies power to load 720 under control of control logic 730 .
  • Current monitor 740 monitors supply of current to load 720 , and interrupts control logic 730 to shut down power supply 710 when an overcurrent condition exists.
  • FIG. 8 illustrates an embodiment of a process of current limiting.
  • Process 800 includes operating the device, monitoring current, ratcheting current down, further operation, determining if a high limit has been exceeded, and temporarily shutting down the device.
  • Process (method) 800 and other processes of this document are implemented as a set of modules, which may be process modules or operations, software modules with associated functions or effects, hardware modules designed to fulfill the process operations, or some combination of the various types of modules, for example.
  • the modules of process 800 and other processes described herein may be rearranged, such as in a parallel or serial fashion, and may be reordered, combined, or subdivided in various embodiments.
  • Process 800 begins with operation of the circuit at module 810 .
  • the current load of the circuit is monitored at module 820 . If the current is not over a first limit, the circuit continues operation at module 810 . If the current is over the first limit, the current is ratcheted down at module 840 . The circuit then continues to operate at module 850 . A determination is made at module 860 as to whether a high or second current limit has been exceeded. If not, the circuit continues operation at module 810 . If the second current limit has been exceeded, then a temporary shutdown at module 870 occurs until the current load decays to an acceptable level.
  • this is accomplished by using a first current limit of 1.7 A and a second current limit of 2.2 A.
  • a first current limit of 1.7 A the system is turned off normally.
  • 2.2 A the system is turned off until the current decays to a low value.

Abstract

A regulator with a high side pass device and a low side pass device coupled in series to the high side pass device is disclosed. The apparatus further includes a control module coupled to the high side pass device and the low side pass device. The control module is coupled to the high side pass device and the low side pass device to control the high side pass device and the low side pass device. The control module is operable to lock out the high side pass device under certain conditions.

Description

    CROSS-REFERENCE TO RELATED APPLICATION
  • This application is a continuation of U.S. patent application Ser. No. 11/216,276, filed Aug. 30, 2005 and titled SHORT CIRCUIT CURRENT RATCHETING IN SWITCH MODE DC/DC VOLTAGE REGULATORS, which claims priority to U.S. Provisional Patent Application No. 60/605,423, filed Aug. 30, 2004 and titled SHORT CIRCUIT CURRENT RATCHETING IN SWITCH MODE DC/DC VOLTAGE REGULATORS, each of which is incorporated herein by reference in its entirety.
  • BACKGROUND
  • A DC/DC voltage regulator is operative to maintain a level output voltage despite variations in power supply voltage or current drawn by a load. Many portable devices require a steady voltage supply such as that provided by a DC/DC voltage regulator. Switch mode regulators can be subject to a phenomenon of current ratcheting at shorted loads due to finite on times to determine an over current condition. Nearly every switch-mode device has a finite loop response time to measure current in the inductor. Depending on the input voltage, the current can rise high enough to cause a catastrophic failure in a device.
  • For this reason, in fixed frequency parts, it is common to use frequency fold-back to change the amount of current ratcheting that a part can see. A common problem caused by frequency fold-back is a large current ripple in the inductor. For this reason, a larger than normal bypass or output capacitor is chosen to reduce the ripple voltage. And if the frequency is folded back too much, the loop may become unstable. Thus, choosing the correct fold-back frequency range for wide application is not an easy task.
  • SUMMARY
  • The present invention is described and illustrated in conjunction with systems, apparatuses and methods. In addition to the aspects of the present invention described in this summary, further aspects of the invention will become apparent by reference to the drawings and by reading the detailed description that follows.
  • In an embodiment, a DC/DC switch mode voltage regulator with a high side pass device and a low side pass device is provided. The voltage regulator includes means for detecting an over current condition over a current limit on the high side pass. The voltage regulator also includes means for locking out the high side pass device and turning on the low side pass device until a second current limit located on the low side pass device is reached if the over current condition is detected.
  • In another embodiment, a method implemented on a DC/DC switch mode voltage regulator with a high side pass device and a low side pass device is provided. The method includes detecting an over current condition over a current limit on the high side pass. The method also includes locking out the high side pass device and turning on the low side pass device until a second current limit located on the low side pass device is reached if the over current condition is detected.
  • In still another embodiment, an apparatus is provided. The apparatus includes a high side pass device. The apparatus also includes a low side pass device coupled in series to the high side pass device. The apparatus further includes a control module coupled to the high side pass device and the low side pass device. The control module is coupled to the high side pass device and the low side pass device to control the high side pass device and the low side pass device.
  • Additionally, the apparatus includes a first resistor coupled in series with the high side pass device and the low side pass device. Furthermore, the apparatus includes a first comparator coupled in parallel with the first resistor. The first comparator has a threshold voltage input differential corresponding to a first current limit, and an output of the first comparator is coupled to the control module. Moreover, the apparatus includes a second comparator coupled to sense current of the high side pass device as a voltage. The second comparator has a threshold voltage input differential corresponding to a second current limit. An output of the second comparator is coupled to the control module. The second current limit is higher than the first current limit. Also, the control module is operable to lock out the high side pass device responsive to the output of the first comparator until a reset signal is received and is operable to lock out the high side pass device responsive to the output of the second comparator until a low current signal is received.
  • BRIEF DESCRIPTION OF THE DRAWINGS
  • The present invention is illustrated in an exemplary manner by the accompanying drawings. The drawings should be understood as exemplary rather than limiting, as the scope of the invention is defined by the claims.
  • FIG. 1 illustrates an embodiment of a DC-DC voltage regulator output.
  • FIG. 2 illustrates current overload in the embodiment of FIG. 1.
  • FIG. 3 illustrates frequency folding in the embodiment of FIG. 1.
  • FIG. 4 illustrates an embodiment of a current overload protection apparatus for the DC-DC voltage regulator output of FIG. 1.
  • FIG. 5 illustrates an alternate embodiment of the current overload protection apparatus for the DC-DC voltage regulator output of FIG. 1.
  • FIG. 6 illustrates current ratcheting in the embodiment of FIG. 4.
  • FIG. 7 illustrates another alternate embodiment of the current overload protection apparatus for the DC-DC voltage regulator output of FIG. 1.
  • FIG. 8 illustrates an embodiment of a process of current limiting.
  • DETAILED DESCRIPTION
  • A system, method and apparatus is provided for Short Circuit Current Ratcheting in Switch Mode DC/DC Voltage Regulators. The specific embodiments described in this document represent exemplary instances of the present invention, and are illustrative in nature rather than restrictive.
  • In the following description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the invention. It will be apparent, however, to one skilled in the art that the invention can be practiced without these specific details. In other instances, structures and devices are shown in block diagram form in order to avoid obscuring the invention.
  • Reference in the specification to “one embodiment” or “an embodiment” means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the invention. The appearances of the phrase “in one embodiment” in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments.
  • The present invention describes, in some embodiments, a new scheme that eliminates frequency fold-back from the protection scheme of switch-mode regulators and allows for a clean startup without the need for a change in switching frequency for the entire duration of operation.
  • In some embodiments, a sense element is used to measure the current in the inductor. A comparator is used to compare the sense element to another matching element that depicts a finite known current threshold indicating the overcurrent conditions. When this current threshold is exceeded, the comparator signals the logic to latch the low side switch on until a low side current limit is reached. This current limit on the low side can be set to any value positive, negative, or zero inductor current depending on the application.
  • A DC/DC switching voltage regulator, in some embodiments, consists of a PWM controller, two controlled pass devices that are connected in series between a supply voltage and ground, an inductor that is connected to the common point between the two pass devices, and a capacitor connected between the output node and ground after the inductor. By modulating the pass devices, the inductor will build up energy and discharge it into the capacitor. The charge and discharge rates are governed by the equation:
  • V = L I T
  • The increase in current in the inductor is
  • dI charge Vin - R onup × dI charge - Vout L d T on
  • where Vin is the supply voltage, Vout is the output voltage, and Ronup is the resistance in the upper pass device. The discharge current in the inductor is defined by the equation:
  • dI discharge = Vout + R ondwn × dI discharge L dT off
  • where Rondwn is the resistance in the lower pass device. During normal operation dIcharge=dIdischarge and dTon and dToff is a function of the switching frequency. Since the loop takes a finite time to respond there is a minimum on time for the switch. This time can be as low as 20 nanoseconds but as high as 200 nanoseconds. This is due to the fact that the upper pass element needs to be turned on to detect the amount of current in the inductor, and then turned off. The length of the minimum on time can be attributed to driver delays, PWM comparator delays, current sense amplifier delay, and so on.
  • Current ratcheting is a condition that exists when dIcharge>dIdischarge. This can occur when the output is shorted to ground, then dTon=dTmin, and Vout is 0. Then the amount of energy discharged by the inductor during the dToff is small, and the current continues to rise cycle by cycle. The conventional way to make sure that the inductor is discharged is by increasing the dToff time, and by lowering the frequency of operation. In accordance with various embodiments, the inductor current is sensed and if the current ratchets above a fixed value, the loop will lock out the upper pass device and latch the lower pass device until the current has decayed to a preset limit.
  • Reference to the figures may provide further understanding of various embodiments. FIG. 1 illustrates an embodiment of a DC-DC voltage regulator output. System 100 includes high and low supply transistors between a power rail and ground, an inductive load and a capacitor. Inductive load 110 may be an actual inductor or a component which operates in a manner similar to an inductor. Capacitor 160 is coupled between inductive load 110 and ground 150. Power is supplied to load 110 through power transistor 120 (current is sourced) from power supply 130. Current may be sunk from inductive load 110 through power transistor 140 to ground 150.
  • This design involves a potential problem, in that the time it takes to turn transistors 120 and 140 on and off may be long enough to allow currents to overload inductor 110. FIG. 2 illustrates current overload in the embodiment of FIG. 1. Current levels approach a limit value, and the system reduces the current level. However, the decay time for the current may not allow the current level to drop to zero. As a result, the device may then increase the current level again, this time overshooting the maximum current limit before the system reduces current again. This typically happens as a result of the frequency at which the system operates—it may reset the voltage regulator before the current decays to an acceptable level.
  • A common response to this problem is to fold frequency—to reduce the operating frequency of the system so that current levels can be reduced acceptably in overlimit situations. FIG. 3 illustrates frequency folding in the embodiment of FIG. 1. Instead of allowing the system to reset and have the current level ratchet up, the current is allowed to decay over a longer time until an acceptable limit is reached. Not shown is the lead-up to this situation, where the device may run to the limit, and then be reduced to a level too high to avoid an overcurrent situation. Frequency folding can avoid the overcurrent situation, but it also slows down operation of the system and the load to which power is supplied.
  • As an alternative, circuitry may be introduced to sense the current level and ensure that overcurrent situations are allowed to decay appropriately. FIG. 4 illustrates an embodiment of a current overload protection apparatus for the DC-DC voltage regulator output of FIG. 1. System 400 includes device 410 (a DC-DC voltage regulator) various exterior circuitry which may be supplied as part of an overall system. Device 410 may be enabled by enable input 493, which is tied to internal enable circuitry 490. Power may be supplied from a power supply which is modeled as capacitor 433.
  • Current into the load 110 through power transistor 120 is monitored passing that current through resistor 450 which is sensed in current sense amplifier 455 (an amplifier which level-shifts the voltage across its inputs and amplifies that voltage). The output of comparator 450 is mixed with the output of an oscillator 485 and provided as input to comparator 480. Along with feedback through feedback module 470 and error amplifier 475, comparator 480 and control module 415, this provides the feedback loop for the pulse width modulator of device 410. Resistors 460 and 465 provide a resistive divider from which a voltage level is drawn for feedback component 470. Similarly, resistor 483 and capacitor 487 provide an RC component which controls the output of comparator 475.
  • Comparator 435 senses current from resistor 440, which is coupled in series with power transistor 140, and provide a set input to flip-flop 445. Comparator 430 senses current through resistor 440 and power transistor 140 (the same current) and provides a reset input to flip-flop 445. These outputs are also provided to control logic 415. Typically, control logic 415 operates gates 420 and 425 to turn power transistors 120 and 140 on and off. However, when an overcurrent condition is sensed, the output of flip-flop 445 causes transistor 140 to turn on and transistor 120 to turn off. Once current through transistor 140 has decayed sufficiently, flip-flop 445 is reset, and normal operation returns. Thus, by altering trip points of comparators 430 and 435, various current levels for overlimit and low current can be set.
  • An alternate embodiment of regulation circuitry may be described without reference to the surrounding pulse width modulation circuitry. FIG. 5 illustrates an alternate embodiment of the current overload protection apparatus for the DC-DC voltage regulator output of FIG. 1. System 500 operates the power supply to load 110. Resistive divider 570 and 575 provides a voltage which is fed back and compared with a reference voltage at comparator 560. The output of comparator 560 is biased with transistor 565, which receives a Vilimit voltage input to determine the bias level. Schmitt-triggered buffer 555 then provides the biased output of comparator 560 as a logic input to flip-flop 530. Flip-flop 520 then controls transistors 120 and 140 (through inverter 525). Note that in a full implementation of this device, buffer 555 may be an error amplifier similar to amplifier 475 of FIG. 4, which would then be integrated into the PWM feedback loop of the over all system. In the illustration of FIG. 5, the PWM feedback loop and other details are not illustrated to avoid obscuring details of the embodiment.
  • Current through transistor 120 can be measured using sense resistor 505 (coupled in series with transistor 120), comparator 515, and Schmitt-triggered comparator 540. Comparator 540 also receives as input the output of transistor 550, which is biased by a voltage Vilimit+X. Current source 545 completes the bias circuitry of this component. Thus, when current through sense resistor 505 causes a voltage exceeding the bias voltage of transistor 550, comparator 540 can set (or reset) the flip-flop 520. This allows for turning off supply of current to load 110. Similarly, when current has decayed sufficiently, this may be sensed through comparator 530, using sense resistor 510 and the output node coupled to load 110, for example. Thus, comparator 530 may reset (or set) flip-flop 520, allowing normal operation to continue.
  • Where exactly sense resistors 505 and 510 are placed, and how exactly overcurrent and undercurrent conditions are sensed may vary in different embodiments. Likewise, the values of Vilimit and Vilimit+X may be chosen as appropriate in various embodiments. Typically, Vilimit+X will be a higher value than Vilimit, and will provide a higher current limit as a limit which can be used to shut down the system and avoid a current overload.
  • Operation of the device or system may be understood with reference to FIG. 6. FIG. 6 illustrates current ratcheting in the embodiment of FIG. 4. Current may rise to Ilimit, and then be ratcheted back down. If the device is operating at too high a frequency, then the current can increase to Ilimit+X. At this point, the device can be shut down (by turning off the high pass transistor 120 and turning on the low pass transistor 140) until the current decays to an acceptable level (as may be defined by a low current value).
  • Various embodiments can be implemented with the same general approach. FIG. 7 illustrates another alternate embodiment of the current overload protection apparatus for the DC-DC voltage regulator output of FIG. 1. System 700 includes a power supply, control logic, load, and current monitor. Power supply module 710 supplies power to load 720 under control of control logic 730. Current monitor 740 monitors supply of current to load 720, and interrupts control logic 730 to shut down power supply 710 when an overcurrent condition exists.
  • The process by which these circuits operate may also be illustrative. FIG. 8 illustrates an embodiment of a process of current limiting. Process 800 includes operating the device, monitoring current, ratcheting current down, further operation, determining if a high limit has been exceeded, and temporarily shutting down the device. Process (method) 800 and other processes of this document are implemented as a set of modules, which may be process modules or operations, software modules with associated functions or effects, hardware modules designed to fulfill the process operations, or some combination of the various types of modules, for example. The modules of process 800 and other processes described herein may be rearranged, such as in a parallel or serial fashion, and may be reordered, combined, or subdivided in various embodiments.
  • Process 800 begins with operation of the circuit at module 810. The current load of the circuit is monitored at module 820. If the current is not over a first limit, the circuit continues operation at module 810. If the current is over the first limit, the current is ratcheted down at module 840. The circuit then continues to operate at module 850. A determination is made at module 860 as to whether a high or second current limit has been exceeded. If not, the circuit continues operation at module 810. If the second current limit has been exceeded, then a temporary shutdown at module 870 occurs until the current load decays to an acceptable level.
  • In one embodiment, this is accomplished by using a first current limit of 1.7 A and a second current limit of 2.2 A. Thus, if the current exceeds 1.7 A, the system is turned off normally. If the current exceeds 2.2 A, then the system is turned off until the current decays to a low value.
  • Features and aspects of various embodiments may be integrated into other embodiments, and embodiments illustrated in this document may be implemented without all of the features or aspects illustrated or described. One skilled in the art will appreciate that although specific examples and embodiments of the system and methods have been described for purposes of illustration, various modifications can be made without deviating from the spirit and scope of the present invention. For example, embodiments of the present invention may be applied to many different types of databases, systems and application programs. Moreover, features of one embodiment may be incorporated into other embodiments, even where those features are not described together in a single embodiment within the present document. Accordingly, the invention is described by the appended claims.

Claims (20)

1. A method implemented on a DC/DC switch mode voltage regulator with a high side pass device and a low side pass device, the method comprising:
detecting an over current condition over a current limit on the high side pass; and
if the over current condition is detected, locking out the high side pass device and turning on the low side pass device until a second current limit located on the low side pass device is reached.
2. The method of claim 1, further comprising:
detecting an over current condition over a lower current limit;
and
if the over current condition over the lower current limit is detected, locking out the high side pass device and turning on the low side pass device until a reset signal is received.
3. The method of claim 2, further comprising:
resetting the DC/DC switch mode voltage regulator, the resetting providing the reset signal.
4. The method of claim 3, further comprising:
providing power through the high side pass device.
5. The method of claim 4, further comprising:
operating the DC/DC switch mode voltage regulator responsive to an enable signal.
6. An apparatus, comprising:
a high side pass device;
a low side pass device coupled in series to the high side pass device;
a control module coupled to the high side pass device and the low side pass device, the control module coupled to the high side pass device and the low side pass device to control the high side pass device and the low side pass device;
a first resistor coupled in series with the high side pass device and the low side pass device;
a first comparator coupled in parallel with the first resistor, the first comparator having a threshold voltage input differential corresponding to a first current limit, an output of the first comparator coupled to the control module;
a second comparator coupled to sense current of the high side pass device as a voltage, the second comparator having a threshold voltage input differential corresponding to a second current limit, an output of the second comparator coupled to the control module, the second current limit higher than the first current limit;
and
wherein the control module is operable to lock out the high side pass device responsive to the output of the first comparator until a reset signal is received and is operable to lock out the high side pass device responsive to the output of the second comparator until a low current signal is received.
7. The apparatus of claim 6, further comprising:
a second resistor coupled in series to the low side pass device;
and
a third comparator coupled in parallel with the second resistor, an output of the third comparator coupled to the control module, the output of the third comparator constituting a low current signal.
8. The apparatus of claim 7, further comprising:
an enable input coupled to the control module;
and
wherein the control module is operable to operate the high and low side pass devices responsive to the enable signal.
9. The apparatus of claim 6, wherein:
the high side pass device and the low side pass device are power MOSFETs.
10. The apparatus of claim 6, wherein:
inputs of the second comparator are coupled in parallel with the low side pass device.
11. The apparatus of claim 6, wherein:
inputs of the second comparator are coupled in parallel with the first resistor.
12. The apparatus of claim 8, further comprising:
a first external input to the apparatus coupled to the control module, the input to receive a voltage from a resistive divider coupled to a load of the apparatus.
13. The apparatus of claim 12, further comprising:
a second external input to the apparatus coupled to the control module, the input to receive a voltage from a resistor and capacitor coupled in series.
14. The apparatus of claim 13, further comprising:
an oscillator coupled to the output of the first comparator to mix the output of the first comparator with an output signal of the oscillator, with the mixed signal provided to the control module.
15. The apparatus of claim 14, further comprising:
a comparator having a first input and a second input, the first input coupled to the mixed signal and the second input coupled to the first external input, an output of the comparator coupled to the control module.
16. A DC/DC switch mode voltage regulator with a high side pass device and a low side pass device comprising:
means for detecting an over current condition over a current limit on the high side pass; and
if the over current condition is detected, means for locking out the high side pass device and turning on the low side pass device until a second current limit located on the low side pass device is reached.
17. The apparatus of claim 16, wherein
the means for detecting includes a sense element and a finite current level comparator to determine an over current condition.
18. The apparatus of claim 16, further comprising:
a means for determining when the over current condition has been removed.
19. The apparatus of claim 16, further comprising:
a latch for overriding the control of a PWM system to keep the high side pass device off and keep the low side pass device on.
20. The apparatus of claim 16, further comprising:
means for enabling the DC/DC switch mode voltage regulator.
US13/016,818 2004-08-30 2011-01-28 Short circuit current ratcheting in switch mode dc/dc voltage regulators Abandoned US20110128654A1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
US13/016,818 US20110128654A1 (en) 2004-08-30 2011-01-28 Short circuit current ratcheting in switch mode dc/dc voltage regulators

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
US60542304P 2004-08-30 2004-08-30
US11/216,276 US7714558B2 (en) 2004-08-30 2005-08-30 Short circuit current ratcheting in switch mode DC/DC voltage regulators
US12/715,959 US7880455B2 (en) 2004-08-30 2010-03-02 Short circuit current ratcheting in switch mode DC/DC voltage regulators
US13/016,818 US20110128654A1 (en) 2004-08-30 2011-01-28 Short circuit current ratcheting in switch mode dc/dc voltage regulators

Related Parent Applications (1)

Application Number Title Priority Date Filing Date
US12/715,959 Continuation US7880455B2 (en) 2004-08-30 2010-03-02 Short circuit current ratcheting in switch mode DC/DC voltage regulators

Publications (1)

Publication Number Publication Date
US20110128654A1 true US20110128654A1 (en) 2011-06-02

Family

ID=36788458

Family Applications (4)

Application Number Title Priority Date Filing Date
US11/216,276 Active 2027-02-25 US7714558B2 (en) 2004-08-30 2005-08-30 Short circuit current ratcheting in switch mode DC/DC voltage regulators
US12/715,959 Active US7880455B2 (en) 2004-08-30 2010-03-02 Short circuit current ratcheting in switch mode DC/DC voltage regulators
US12/776,668 Active 2025-12-09 US8085025B2 (en) 2004-08-30 2010-05-10 Short circuit current ratcheting in switch mode DC/DC voltage regulators
US13/016,818 Abandoned US20110128654A1 (en) 2004-08-30 2011-01-28 Short circuit current ratcheting in switch mode dc/dc voltage regulators

Family Applications Before (3)

Application Number Title Priority Date Filing Date
US11/216,276 Active 2027-02-25 US7714558B2 (en) 2004-08-30 2005-08-30 Short circuit current ratcheting in switch mode DC/DC voltage regulators
US12/715,959 Active US7880455B2 (en) 2004-08-30 2010-03-02 Short circuit current ratcheting in switch mode DC/DC voltage regulators
US12/776,668 Active 2025-12-09 US8085025B2 (en) 2004-08-30 2010-05-10 Short circuit current ratcheting in switch mode DC/DC voltage regulators

Country Status (3)

Country Link
US (4) US7714558B2 (en)
CN (3) CN1790885B (en)
TW (1) TWI301686B (en)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20100253296A1 (en) * 2009-04-03 2010-10-07 Texas Instruments Incorporated Symmetric sample and hold over-current sensing method and apparatus
US20100312505A1 (en) * 2007-10-30 2010-12-09 Frank Berger Short-circuit recognition method for an electric network
US11112464B2 (en) 2017-12-06 2021-09-07 Denso Corporation Signal output device

Families Citing this family (57)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1790885B (en) * 2004-08-30 2011-05-04 美国芯源系统股份有限公司 Methdo and device for controlling short circuit current of switch mode DC/DC voltage regulators
US7521907B2 (en) 2006-03-06 2009-04-21 Enpirion, Inc. Controller for a power converter and method of operating the same
DE112007001292B8 (en) * 2006-05-29 2015-09-24 Autonetworks Technologies, Ltd. Power supply controller
US7893676B2 (en) * 2006-07-20 2011-02-22 Enpirion, Inc. Driver for switch and a method of driving the same
US7439716B2 (en) * 2006-09-12 2008-10-21 Semiconductor Components Industries, L.L.C. DC-DC converter and method
US8488289B2 (en) * 2006-09-27 2013-07-16 International Rectifier Corporation Current protection circuit for intelligent power switch
JP4946508B2 (en) * 2007-02-28 2012-06-06 株式会社日立製作所 Semiconductor circuit
GB2451467B (en) * 2007-07-28 2013-01-16 Zetex Semiconductors Plc Current driving method and circuit
CN101378228B (en) * 2007-08-28 2012-07-04 比亚迪股份有限公司 Power-supply switching control device and power-supply circuit
US20090116153A1 (en) * 2007-11-05 2009-05-07 Chien-Liang Lin Power conversion system and over-load protection device thereof
TW200929879A (en) * 2007-12-28 2009-07-01 Advanced Analog Technology Inc PWM control circuit and the chip thereof
TWM340549U (en) * 2008-04-01 2008-09-11 Richtek Technology Corp Apparatus for decreasing internal power loss in integrated circuit package
US8692532B2 (en) * 2008-04-16 2014-04-08 Enpirion, Inc. Power converter with controller operable in selected modes of operation
US8410769B2 (en) * 2008-04-16 2013-04-02 Enpirion, Inc. Power converter with controller operable in selected modes of operation
US7679342B2 (en) * 2008-04-16 2010-03-16 Enpirion, Inc. Power converter with power switch operable in controlled current mode
US8541991B2 (en) * 2008-04-16 2013-09-24 Enpirion, Inc. Power converter with controller operable in selected modes of operation
US9246390B2 (en) 2008-04-16 2016-01-26 Enpirion, Inc. Power converter with controller operable in selected modes of operation
US8686698B2 (en) 2008-04-16 2014-04-01 Enpirion, Inc. Power converter with controller operable in selected modes of operation
US7939963B2 (en) * 2008-11-06 2011-05-10 Zippy Technology Corp. Power supply providing multiple synchronous outputs
US8698463B2 (en) 2008-12-29 2014-04-15 Enpirion, Inc. Power converter with a dynamically configurable controller based on a power conversion mode
US9548714B2 (en) * 2008-12-29 2017-01-17 Altera Corporation Power converter with a dynamically configurable controller and output filter
KR101602474B1 (en) * 2009-03-05 2016-03-10 페어차일드코리아반도체 주식회사 Protection circuit resonant converter comprising the protection circuit and protecting method of the resonant converter
GB0912745D0 (en) * 2009-07-22 2009-08-26 Wolfson Microelectronics Plc Improvements relating to DC-DC converters
US8710814B1 (en) * 2009-10-05 2014-04-29 Adaptive Digital Power, Inc. Systems and methods for switching supply load current estimation
US8879283B2 (en) * 2009-11-05 2014-11-04 On-Bright Electronics (Shanghai) Co., Ltd. System and method providing protection in the event of current sensing failure for power converter
CN101860072B (en) * 2010-04-19 2013-01-30 成都康瑞特科技开发有限责任公司 Multi-power parallel-combination welding power supply
US8867295B2 (en) 2010-12-17 2014-10-21 Enpirion, Inc. Power converter for a memory module
US8937464B2 (en) * 2011-07-15 2015-01-20 Synopsys Inc. High voltage generation system and method employing a charge pump and producing discrete voltage values
GB201117977D0 (en) * 2011-10-19 2011-11-30 Melexis Technologies Nv Direct current control with low E-M emission
CN103186152B (en) * 2011-12-29 2015-01-14 比亚迪股份有限公司 Hysteresis comparison control method
TWI463770B (en) * 2012-12-05 2014-12-01 Anpec Electronics Corp Synchronous buck dc-dc converter with soft-stop function
US11159009B2 (en) 2013-04-01 2021-10-26 Qualcomm Incorporated Voltage regulator over-current protection
KR101804713B1 (en) * 2013-10-18 2018-01-10 미쓰비시덴키 가부시키가이샤 Dc power source device, motor drive device, air conditioner, and refrigerator
CN105099184B (en) * 2014-04-17 2017-12-29 钰太芯微电子科技(上海)有限公司 A kind of underload switch power supply chip
TW201608796A (en) 2014-08-28 2016-03-01 鴻海精密工業股份有限公司 Switching charge circuit
CN105375541A (en) * 2014-08-28 2016-03-02 国基电子(上海)有限公司 Switching type charging circuit
CN104242644B (en) * 2014-10-11 2017-04-12 成都芯源系统有限公司 Control circuit and control method for switch converter
DE102014224639A1 (en) * 2014-12-02 2016-06-02 Robert Bosch Gmbh Method and monitoring device for detecting a fault current for a control device for controlling a multiphase actuator
US9509217B2 (en) 2015-04-20 2016-11-29 Altera Corporation Asymmetric power flow controller for a power converter and method of operating the same
US10855178B2 (en) 2015-05-29 2020-12-01 Infineon Technologies Austria Ag Discrete power stage transistor dies of a DC-DC converter under an inductor
US9972998B2 (en) * 2015-06-08 2018-05-15 Dialog Semiconductor (Uk) Limited Short circuit self-protected DC-to-DC buck converters
CN104980013A (en) * 2015-07-15 2015-10-14 常州顶芯半导体技术有限公司 Time switch AC power circuit
JP6730835B2 (en) * 2016-04-06 2020-07-29 ローム株式会社 Overcurrent detection circuit
US20180091051A1 (en) * 2016-09-23 2018-03-29 Apple Inc. Control and Detection of Average Phase Current in Switching DC-DC Power Converters
CN108011504B (en) * 2016-11-01 2020-04-28 台达电子工业股份有限公司 Driving method and driving device
KR102510906B1 (en) * 2016-11-16 2023-03-15 삼성전자주식회사 Semiconductor device and system
CN109510175B (en) * 2017-09-15 2020-03-06 华硕电脑股份有限公司 Voltage conversion device and control method thereof
US11340641B2 (en) 2018-11-07 2022-05-24 Mediatek Inc. Hybrid voltage regulator using bandwidth suppressed series regulator and associated voltage regulating method
DE112019007209T5 (en) 2019-04-10 2021-12-30 Danfoss Power Electronics A/S Method for determining a low impedance state at the output of an electrical converter, control unit, computer program product and electrical converter
TWI710885B (en) * 2019-05-07 2020-11-21 宏碁股份有限公司 Power supply device
CN110174549B (en) * 2019-05-24 2021-09-10 北京无线电测量研究所 Low-current dual monitoring circuit for amplifying power dividing component and amplifying power dividing device
TWM588919U (en) 2019-07-03 2020-01-01 力智電子股份有限公司 Power conversion circuit and simulation current signal generation circuit thereof
CN110707664B (en) * 2019-10-30 2020-10-02 珠海格力电器股份有限公司 IPM protection detection circuit
CN111864697B (en) * 2020-09-01 2022-05-24 臻驱科技(上海)有限公司 Overcurrent protection circuit and method and system for judging whether power supply is overhauled
GB2606373A (en) * 2021-05-05 2022-11-09 Eaton Intelligent Power Ltd Power inverter and method for controlling a power inverter
US11757351B2 (en) * 2021-07-30 2023-09-12 Texas Instruments Incorporated Dynamic overcurrent limit threshold for a voltage regulator
US11722053B2 (en) * 2021-12-23 2023-08-08 Infineon Technologies Austria Ag Over current protection concept for negative load current of power device gate drivers

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6396252B1 (en) * 2000-12-14 2002-05-28 National Semiconductor Corporation Switching DC-to-DC converter with discontinuous pulse skipping and continuous operating modes without external sense resistor
US6646425B2 (en) * 2002-02-21 2003-11-11 Texas Instruments Incorporated Multi-cell voltage regulator and method thereof

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5502610A (en) * 1993-09-02 1996-03-26 Micrel, Inc. Switching regulator having high current prevention features
US6087787A (en) 1998-11-23 2000-07-11 Linear Technology Corporation Fluorescent-lamp excitation circuit with frequency and amplitude control and methods for using same
JP2003150254A (en) 2001-11-09 2003-05-23 Seiko Instruments Inc Voltage regulator
CN1790885B (en) * 2004-08-30 2011-05-04 美国芯源系统股份有限公司 Methdo and device for controlling short circuit current of switch mode DC/DC voltage regulators

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6396252B1 (en) * 2000-12-14 2002-05-28 National Semiconductor Corporation Switching DC-to-DC converter with discontinuous pulse skipping and continuous operating modes without external sense resistor
US6646425B2 (en) * 2002-02-21 2003-11-11 Texas Instruments Incorporated Multi-cell voltage regulator and method thereof

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
Maxim Integrated Product, 09/2005,Maxim Integrated Product,Rev. 4, 1-32 *

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20100312505A1 (en) * 2007-10-30 2010-12-09 Frank Berger Short-circuit recognition method for an electric network
US8335656B2 (en) * 2007-10-30 2012-12-18 Siemens Aktiengesellschaft Short-circuit recognition method for an electric network
US20100253296A1 (en) * 2009-04-03 2010-10-07 Texas Instruments Incorporated Symmetric sample and hold over-current sensing method and apparatus
US8044644B2 (en) * 2009-04-03 2011-10-25 Texas Instruments Incorporated Symmetric sample and hold over-current sensing method and apparatus
US11112464B2 (en) 2017-12-06 2021-09-07 Denso Corporation Signal output device

Also Published As

Publication number Publication date
CN1790885A (en) 2006-06-21
TWI301686B (en) 2008-10-01
CN101917116A (en) 2010-12-15
US20100220421A1 (en) 2010-09-02
US7714558B2 (en) 2010-05-11
US20060050449A1 (en) 2006-03-09
CN1790885B (en) 2011-05-04
US8085025B2 (en) 2011-12-27
TW200620778A (en) 2006-06-16
US7880455B2 (en) 2011-02-01
US20100157487A1 (en) 2010-06-24
CN102097938A (en) 2011-06-15
CN101917116B (en) 2013-03-27

Similar Documents

Publication Publication Date Title
US7714558B2 (en) Short circuit current ratcheting in switch mode DC/DC voltage regulators
US10218265B2 (en) State space-based multi-level voltage regulator system
JP3254199B2 (en) DC-DC converter having inductor current detector and adjustment method thereof
US6671143B2 (en) Technique for limiting current through a reactive element in a voltage converter
US7254000B1 (en) Over voltage protection scheme for synchronous buck converter
US6469481B1 (en) Parallel RC current detection circuit and DC/DC converter with a parallel RC current detection circuit
US9660516B2 (en) Switching controller with reduced inductor peak-to-peak ripple current variation
US8018694B1 (en) Over-current protection for a power converter
US9024597B2 (en) System and method for controlling DCM-CCM oscillation in a current-controlled switching mode power supply converter
US8059432B2 (en) PWM controller having drive control with input voltage sensing and method therefor
US8233256B2 (en) System and method for programming and controlling over current trip point limits in voltage regulators
US20150362550A1 (en) Circuits and Techniques for Detecting an Open Pin Condition of an Integrated Circuit
US10790737B2 (en) Current threshold regulation method used in switching converters
WO2001063735A1 (en) Power converter mode transistioning method and apparatus
US9712041B2 (en) Apparatuses and methods for over-current protection of DC-DC voltage converters
JP2002084742A (en) Control method for overcurrent protecting operation of step-down dc-dc converter, judging integrated circuit for overcurrent protecting operation of step-down dc-dc converter, judging circuit module for overcurrent protecting operation of step-down dc-dc converter, control integrated circuit of step-down dc-dc converter, and board for computer
KR20060081668A (en) Dc/dc converter with current limit protection
WO2023009885A1 (en) Dynamic overcurrent limit threshold
JP5312781B2 (en) Switching power supply circuit
US20110019315A1 (en) Over-current protection for dc-to-dc converters
EP3823146A1 (en) Voltage feedback continuity failure detection in voltage regulators
JP2001136734A (en) Overcurrent protective circuit
Semiconductort Synchronous Rectification DC/DC Converter Programmable Integrated Controller

Legal Events

Date Code Title Description
STCB Information on status: application discontinuation

Free format text: ABANDONED -- FAILURE TO RESPOND TO AN OFFICE ACTION