WO2017201214A1 - Generating the under voltage protection threshold - Google Patents

Generating the under voltage protection threshold Download PDF

Info

Publication number
WO2017201214A1
WO2017201214A1 PCT/US2017/033193 US2017033193W WO2017201214A1 WO 2017201214 A1 WO2017201214 A1 WO 2017201214A1 US 2017033193 W US2017033193 W US 2017033193W WO 2017201214 A1 WO2017201214 A1 WO 2017201214A1
Authority
WO
WIPO (PCT)
Prior art keywords
voltage
droop
iocl
controller
rdroop
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.)
Ceased
Application number
PCT/US2017/033193
Other languages
French (fr)
Inventor
Vikram Gakhar
Muthusubramanian VENKATESWARAN
Preetam Tadeparthy
Vikas Lakhanpal
Kuang-Yao Cheng
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.)
Texas Instruments Japan Ltd
Texas Instruments Inc
Original Assignee
Texas Instruments Japan Ltd
Texas Instruments Inc
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
Application filed by Texas Instruments Japan Ltd, Texas Instruments Inc filed Critical Texas Instruments Japan Ltd
Publication of WO2017201214A1 publication Critical patent/WO2017201214A1/en
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
    • H02H3/00—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection
    • H02H3/24—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection responsive to undervoltage or no-voltage
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
    • H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
    • H02H7/10—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for converters; for rectifiers
    • H02H7/12—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for converters; for rectifiers for static converters or rectifiers
    • H02H7/1213—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for converters; for rectifiers for static converters or rectifiers for DC-DC converters
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
    • H02H3/00—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection
    • H02H3/006—Calibration or setting of parameters

Definitions

  • Under voltage protection is a feature of voltage regulators where the regulator takes an action such as raising an alarm or shutting itself down when its output voltage is pulled too low by an external load. The protection kicks in when the output voltage falls below a certain threshold.
  • non-droop voltage regulators generating the under voltage (UV) threshold is straightforward.
  • the droop voltage needs to be added to the UV threshold. Generating droop voltage needs additional circuitry that adds to silicon area and complexity.
  • the controller includes means for generating a droop voltage portion of an under voltage protection threshold by using a realization that an under voltage condition only occurs when an overcurrent condition exists, so that the droop portion comprises the overcurrent limit value multiplied by droop resistance.
  • the controller includes: a signal generator to generate a voltage representative of a droop voltage at a constant current output; a circuit to add the droop voltage at a constant current output to a user-determined under voltage specification voltage to create a voltage representative of the sum; and a comparator to compare an output voltage of the regulator with the sum voltage to establish a new under voltage protection threshold.
  • the controller includes: a circuit to apply a digital representation of a droop voltage at a constant output current to a first input of a digital to analog converter; a circuit to apply a signal representing output voltage of the voltage regulator minus the reference voltage to a second input of the digital to analog converter; and a circuit to apply an output of the digital to analog converter to a first input of a comparator.
  • a second input of the comparator is coupled to a signal representing the reference voltage minus a user-determined under voltage specification voltage to create a voltage representative of the difference.
  • the comparator is to compare the signals at the first and second inputs of the comparator to establish a new under voltage protection threshold.
  • FIG. 1 shows a principle of output voltage droop.
  • FIG. 2 shows a control principle for a controller for a voltage regulator.
  • FIG. 3 shows an embodiment of a control circuit for a voltage regulator in accordance with principles of example embodiments.
  • FIG. 4 shows an alternate embodiment of the control circuit for a voltage regulator in accordance with principles of example embodiments.
  • the droop voltage is described with reference to a graph 100 in FIG. 1.
  • the voltage regulator is required to regulate and output voltage that droops down from the reference voltage (VDAC) by an amount proportional to the load current:
  • VOUT VDAC - RDROOP*IOUT
  • VOUT is the output voltage of the regulator
  • VDAC is a voltage reference to which the output of the voltage regulator is regulated
  • R d roo p is an effective resistance to voltage regulator
  • IOUT is the output current of the voltage regulator.
  • a fault condition (such as excessive load or a short) can cause the output voltage to be lower than its expected value.
  • An excursion equal to the UVP threshold in the output voltage can be tolerated. Beyond such threshold, the voltage regulator must take some action, such as raising a flag or turning off the output.
  • the voltage regulator can have an over-current-limit feature, where it does not allow load currents higher than the overcurrent limit (OCL ) threshold to flow out of its output.
  • OCL overcurrent limit
  • the UVP threshold is required to be the UVP threshold spec (user selected) plus the droop voltage, where the UVP threshold spec is a fixed voltage.
  • the actual UVP threshold at which the UVP condition is detected is:
  • VOUT VDAC - IOUT*R DROOP - UVP SPEC
  • UVP SPEC is a user supplied fixed voltage
  • the output current IOUT is used to generate the UVP threshold, it would involve sensing the output current and converting it into a voltage proportional to RDROOP before adding it to the UVP SPEC voltage. This would need at least one amplifier and a few resistors. However, because IOCL can be used in place of IOUT and IOCL threshold and RDROOP are fixed numbers, the sensed IOUT is not required to be converted to a droop voltage, and an amplifier can be eliminated. The implementation is a constant voltage threshold generation (e.g., a fixed current flowing through a fixed resistance).
  • the circuit 300 in FIG. 3 includes comparator 302, resistor 306 and current source 304.
  • IOCL_R DRO op is the droop voltage at constant output current.
  • Vref is internally generated or externally provided and used as common mode for all the blocks. It can take a value of zero if a negative value case is not required.
  • a UVP threshold spec signal is referred to the same VREF.
  • VUVP_SPEC is a user-determined voltage
  • the circuit 400 in FIG. 4 includes comparator 402 and thermometric DAC 404.
  • VUVP_SPEC is a user-determined voltage

Landscapes

  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Dc-Dc Converters (AREA)

Abstract

In described examples of a voltage regulator (300) having a regulated output voltage that droops down from a reference voltage (VDAC), an improvement includes generating a droop voltage portion of an under voltage protection threshold (IOCL*DROOP) by using a realization that an under voltage condition only occurs when an overcurrent condition (IOCL) exists, so that the droop portion includes the overcurrent limit value multiplied by droop resistance.

Description

GENERATING THE UNDER VOLTAGE PROTECTION THRESHOLD
BACKGROUND
[0001] Under voltage protection is a feature of voltage regulators where the regulator takes an action such as raising an alarm or shutting itself down when its output voltage is pulled too low by an external load. The protection kicks in when the output voltage falls below a certain threshold. In non-droop voltage regulators, generating the under voltage (UV) threshold is straightforward. However, in finite-droop voltage regulators, the droop voltage needs to be added to the UV threshold. Generating droop voltage needs additional circuitry that adds to silicon area and complexity.
SUMMARY
[0002] In described examples of a controller for a voltage regulator having a regulated output voltage that droops down from a reference voltage, the controller includes means for generating a droop voltage portion of an under voltage protection threshold by using a realization that an under voltage condition only occurs when an overcurrent condition exists, so that the droop portion comprises the overcurrent limit value multiplied by droop resistance.
[0003] In described examples of a controller for a voltage regulator having a regulated output voltage that droops down from a reference voltage, and having an under voltage limit circuit, the controller includes: a signal generator to generate a voltage representative of a droop voltage at a constant current output; a circuit to add the droop voltage at a constant current output to a user-determined under voltage specification voltage to create a voltage representative of the sum; and a comparator to compare an output voltage of the regulator with the sum voltage to establish a new under voltage protection threshold.
[0004] In further described examples of a controller for a voltage regulator having a regulated output voltage that droops down from a reference voltage, and having an under voltage limit circuit, the controller includes: a circuit to apply a digital representation of a droop voltage at a constant output current to a first input of a digital to analog converter; a circuit to apply a signal representing output voltage of the voltage regulator minus the reference voltage to a second input of the digital to analog converter; and a circuit to apply an output of the digital to analog converter to a first input of a comparator. A second input of the comparator is coupled to a signal representing the reference voltage minus a user-determined under voltage specification voltage to create a voltage representative of the difference. The comparator is to compare the signals at the first and second inputs of the comparator to establish a new under voltage protection threshold.
BRIEF DESCRIPTION OF THE DRAWINGS
[0005] FIG. 1 shows a principle of output voltage droop.
[0006] FIG. 2 shows a control principle for a controller for a voltage regulator.
[0007] FIG. 3 shows an embodiment of a control circuit for a voltage regulator in accordance with principles of example embodiments.
[0008] FIG. 4 shows an alternate embodiment of the control circuit for a voltage regulator in accordance with principles of example embodiments.
DETAILED DESCRIPTION OF EXAMPLE EMBODEVIENTS
[0009] This solution eliminates additional circuitry by generating the droop voltage and the UV threshold in a simpler manner, exploiting the fact that (in this example) an under voltage condition only occurs when an over-current condition exists.
[0010] The droop voltage is described with reference to a graph 100 in FIG. 1. In this example, the voltage regulator is required to regulate and output voltage that droops down from the reference voltage (VDAC) by an amount proportional to the load current:
VOUT = VDAC - RDROOP*IOUT
where VOUT is the output voltage of the regulator, VDAC is a voltage reference to which the output of the voltage regulator is regulated, Rdroop is an effective resistance to voltage regulator, and IOUT is the output current of the voltage regulator.
[0011] A fault condition (such as excessive load or a short) can cause the output voltage to be lower than its expected value. An excursion equal to the UVP threshold in the output voltage can be tolerated. Beyond such threshold, the voltage regulator must take some action, such as raising a flag or turning off the output.
[0012] The voltage regulator can have an over-current-limit feature, where it does not allow load currents higher than the overcurrent limit (OCL ) threshold to flow out of its output.
[0013] In this type of example, whenever a UVP condition exists, an OCL condition also exists. Referring to the graph 200 in FIG. 2, because the voltage regulator maintains a constant output current (equal to the OCL threshold, IOCL) during the OCL condition, the droop value in the UVP condition is RDROOp*IOCL. This equation gets modified based on linear regulator or switching regulator. If linear IOCL is the same as the current limit in the system, in case of switching regulator depending on the implementation of OCL, the value of IOCL will modify into either IOCL (average current limit), IOCL+Rippe/2 if valley mode OCL, or IOCL-Ripple/2 if peak mode control.
[0014] In this type of example, the UVP threshold is required to be the UVP threshold spec (user selected) plus the droop voltage, where the UVP threshold spec is a fixed voltage. Thus, the actual UVP threshold at which the UVP condition is detected is:
VOUT = VDAC - IOUT*RDROOP - UVP SPEC
where UVP SPEC is a user supplied fixed voltage.
[0015] Accordingly, it is the same as:
VOUT = VDAC - 7OCJ*RDR00P - UVP SPEC (since IOUT = IOCL in UVP condition)
[0016] If the output current IOUT is used to generate the UVP threshold, it would involve sensing the output current and converting it into a voltage proportional to RDROOP before adding it to the UVP SPEC voltage. This would need at least one amplifier and a few resistors. However, because IOCL can be used in place of IOUT and IOCL threshold and RDROOP are fixed numbers, the sensed IOUT is not required to be converted to a droop voltage, and an amplifier can be eliminated. The implementation is a constant voltage threshold generation (e.g., a fixed current flowing through a fixed resistance). The circuit 300 in FIG. 3 includes comparator 302, resistor 306 and current source 304.
[0017] The inequality realized by the circuit is:
VOUT < VDAC - (IOCL RDROOP + SPEC)
where IOCL_RDROop is the droop voltage at constant output current.
[0018] In a second embodiment, instead of sensing the VOUT directly, a more accurate signal represents VOUT in the form of VOUT - VDAC + VREF, where VREF is a fixed reference voltage to ensure the signal Vout-VDAC has swing on both sides. Vref is internally generated or externally provided and used as common mode for all the blocks. It can take a value of zero if a negative value case is not required.
[0019] To limit the input common mode of the comparator, a UVP threshold spec signal is referred to the same VREF.
(VREF - VUVP SPEC)
where VUVP_SPEC is a user-determined voltage.
[0020] The circuit 400 in FIG. 4 includes comparator 402 and thermometric DAC 404.
[0021] The inequality realized by the circuit is still the same:
VOUT < VDAC - (IOCL RDROOP + SPEC)
where VUVP_SPEC is a user-determined voltage.
[0022] This technique can be used with linear or switching regulators.
[0023] Modifications are possible in the described embodiments, and other embodiments are possible, within the scope of the claims.

Claims

CLAIMS What is claimed is:
1. A controller for a voltage regulator having a regulated output voltage that droops down from a reference voltage, the controller comprising:
means for generating a droop voltage portion of an under voltage protection threshold by using a realization that an under voltage condition only occurs when an overcurrent condition exists, so that the droop portion comprises the overcurrent limit value multiplied by droop resistance.
2. The controller of claim 1, further comprising an under voltage limit circuit to realize an inequality of:
VOUT < VDAC - (IOCL RDROOP + VUVP SPEC),
wherein IOCL RDROOP is the droop voltage at constant output current, VOUT is the output voltage of the regulator, VDAC is the reference voltage, and VUVP_SPEC is a user-determined fixed voltage.
3. The controller of claim 1, wherein the reference voltage is applied to a first input of a comparator through a resistor, the first input also being coupled by a current source to a reference voltage to generate the voltage IOCL RDROOP + VU PJSPEC,
wherein IOCL RDROOP is the droop voltage at constant output current, and VUVP_SPEC is a user-determined voltage; and
a second input of the comparator being coupled to VOUT to generate the under voltage protection threshold.
4. A controller for a voltage regulator having a regulated output voltage that droops down from a reference voltage, and having an under voltage limit circuit, the controller comprising: a signal generator to generate a voltage representative of a droop voltage at a constant current output;
a circuit to add the droop voltage at a constant current output to a user-determined under voltage specification voltage to create a voltage representative of the sum; and
a comparator to compare an output voltage of the regulator with the sum voltage to establish a new under voltage protection threshold.
5. The controller of claim 4, wherein the under voltage limit circuit realizes an inequality of: VOUT < VDAC - (IOCL RDROOP + Vuw SPEC),
wherein IOCL RDROOP is the droop voltage at constant output current, VOUT is the output voltage of the regulator, VDAC is the reference voltage, and VU PJSPEC is a user-determined fixed voltage.
6. The controller of claim 5, wherein the reference voltage is applied to a first input of a comparator through a resistor, the first input also being coupled by a current source to a reference voltage to generate the voltage IOCL RDROOP + VUVPJSPEC,
wherein IOCL RDROOP is the droop voltage at constant output current, and VUVP_SPEC is a user-determined voltage; and
a second input of the comparator being coupled to VOUT to generate the under voltage protection threshold.
7. A controller for a voltage regulator having a regulated output voltage that droops down from a reference voltage, and having an under voltage limit circuit, the controller comprising: a circuit to apply a digital representation of a droop voltage at a constant output current to a first input of a digital to analog converter;
a circuit to apply a signal representing output voltage of the voltage regulator minus the reference voltage to a second input of the digital to analog converter; and
a circuit to apply an output of the digital to analog converter to a first input of a comparator, wherein a second input of the comparator is coupled to a signal representing the reference voltage minus a user-determined under voltage specification voltage to create a voltage representative of the difference;
the comparator being to compare the signals at the first and second inputs of the comparator to establish a new under voltage protection threshold.
8. The controller of claim 7, wherein the under voltage limit circuit realizes an inequality of:
VOUT < VDAC - (IOCL RDROOP + VUVP SPEC),
wherein IOCL RDROOP is the droop voltage at constant output current, VOUT is the output voltage of the regulator, VDAC is the reference voltage, and VUVPJSPEC is a user-determined fixed voltage.
PCT/US2017/033193 2016-05-17 2017-05-17 Generating the under voltage protection threshold Ceased WO2017201214A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
IN201641017606 2016-05-17
IN201641017606 2016-05-17

Publications (1)

Publication Number Publication Date
WO2017201214A1 true WO2017201214A1 (en) 2017-11-23

Family

ID=60325597

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/US2017/033193 Ceased WO2017201214A1 (en) 2016-05-17 2017-05-17 Generating the under voltage protection threshold

Country Status (1)

Country Link
WO (1) WO2017201214A1 (en)

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2476927A1 (en) * 1980-02-22 1981-08-28 Labo Electronique Physique Battery voltage regulator - uses two threshold detectors to provide both over-voltage and under-voltage compensation via discharge path or auxiliary supply
US5666044A (en) * 1995-09-29 1997-09-09 Cherry Semiconductor Corporation Start up circuit and current-foldback protection for voltage regulators
CN104283472A (en) * 2013-07-03 2015-01-14 环旭电子股份有限公司 Voltage regulator and its over-low voltage protection circuit
US20150015215A1 (en) * 2013-07-03 2015-01-15 Universal Global Scientific Industrial Co., Ltd. Voltage regulator, under-voltage protection circuit thereof and voltage regulation system

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2476927A1 (en) * 1980-02-22 1981-08-28 Labo Electronique Physique Battery voltage regulator - uses two threshold detectors to provide both over-voltage and under-voltage compensation via discharge path or auxiliary supply
US5666044A (en) * 1995-09-29 1997-09-09 Cherry Semiconductor Corporation Start up circuit and current-foldback protection for voltage regulators
CN104283472A (en) * 2013-07-03 2015-01-14 环旭电子股份有限公司 Voltage regulator and its over-low voltage protection circuit
US20150015215A1 (en) * 2013-07-03 2015-01-15 Universal Global Scientific Industrial Co., Ltd. Voltage regulator, under-voltage protection circuit thereof and voltage regulation system

Similar Documents

Publication Publication Date Title
JP5950591B2 (en) Voltage regulator
US8190933B2 (en) Bi-directional control of power adapter and load
JP2005086843A (en) Output control device of power supply source
EP2894537B1 (en) Voltage regulator
US11467611B2 (en) Current limiting electronic fuse circuit
US20190011944A1 (en) Regulator circuit
US9166473B2 (en) DC/DC power converter with feedback control operable in linear and non-linear modes
JP2013120604A (en) Power management system
KR20060127070A (en) Overcurrent Detection Circuit and Regulator with the Same
US10261534B2 (en) Method and system for an adaptive low-dropout regulator
KR20140110792A (en) Constant voltage circuit
CN109839979B (en) Low-voltage-drop voltage stabilizer and power output device
US20130257409A1 (en) Control circuit for dc-dc converter, dc-dc converter, and control method of dc-dc converter
JP2018160224A (en) Dual input power management method and system
JP2021018657A (en) Series regulator
JP7472151B2 (en) Overcurrent Protection Circuit
JP2005157743A (en) Load driving apparatus and load drive system
US8680835B2 (en) Buck DC-to-DC converter having a novel output protection mechanism
US20140300999A1 (en) Excess power protection circuit
KR101394272B1 (en) Low dropout Voltage regulator with Current Limiter
KR20150100235A (en) Soft-start circuit and dc-dc convertor having the same
KR19990072684A (en) Switching regulator control circuit of PWM system and switching regulator thereof
US9160159B2 (en) Circuit breaker and method of controlling a power transistor with a circuit breaker
US10191502B2 (en) Power supply device
US7705574B2 (en) Remote power controller with power sharing circuit

Legal Events

Date Code Title Description
NENP Non-entry into the national phase

Ref country code: DE

121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 17800127

Country of ref document: EP

Kind code of ref document: A1

122 Ep: pct application non-entry in european phase

Ref document number: 17800127

Country of ref document: EP

Kind code of ref document: A1