CN110994559B - Power module output end short-circuit protection circuit - Google Patents
Power module output end short-circuit protection circuit Download PDFInfo
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- CN110994559B CN110994559B CN201911239440.1A CN201911239440A CN110994559B CN 110994559 B CN110994559 B CN 110994559B CN 201911239440 A CN201911239440 A CN 201911239440A CN 110994559 B CN110994559 B CN 110994559B
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- 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
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Abstract
The invention provides a short-circuit protection circuit for an output end of a power supply module. The circuit comprises a serial voltage stabilizing circuit, a plurality of power modules, an auxiliary control circuit and a control MCU. The adjusting tube in the series voltage stabilizing circuit is controlled by combining a hardware control signal and a software control signal. And the hardware control signal is generated when the power is on and the MCU is not operated and is used for turning on the adjusting tube, and the duration time is T1. After the hardware control signal disappears, the hardware control signal is controlled by a software control signal sent by the control MCU which is powered on, the time from power-on to software control signal sending is T2, and T2 is less than T1. The control MCU detects whether the output end of the power supply module connected to the output end of the serial voltage stabilizing circuit is short-circuited, if so, the adjusting tube is connected, and if not, the adjusting tube is kept to be connected. Compared with the prior art, the scheme provided by the invention completely disconnects the external power supply and avoids generating large current in the whole power supply module when the output end of the power supply module is short-circuited.
Description
Technical Field
The invention provides a short-circuit protection circuit for an output end of a power supply module, and relates to the field of short-circuit detection and protection of the output end of the power supply module.
Background
The existing power module circuit generally adopts a mode that the output end of a series voltage stabilizing circuit is connected with the input end of a power module to supply power. One embodiment in the prior art is shown in fig. 1, a series voltage stabilizing circuit is composed of a resistor R1, a triode Q1 and a zener diode D2, and the regulated voltage value of D2 is selected according to actual conditions. The triode Q1 is an adjusting tube of the series voltage stabilizing circuit, the emitter of the triode Q1 is used as the output end of the series voltage stabilizing circuit and is connected with the input ends of the rear power supply modules U1 and U2, and the collector of the triode Q1 is connected with an external power supply VIN; the external power source VIN supplies power to the power supply modules U1 and U2 through the Q1. As can be seen from fig. 1, when the output terminals of U1 and U2 are short-circuited, the protection measures provided by the power supply modules themselves are completely relied on, and at this time, a large current occurs in U1 and U2, and the power supply modules U1 and U2 cannot completely stop working; and the current can flow through the triode Q1, so that the loss of the triode Q1 is increased, the heat is serious, and even the situation of damage occurs.
Disclosure of Invention
The protection device aims at the situation that the existing power module completely depends on the protection measures provided by the power module when the output end of the power module is in short circuit, the power module cannot completely stop working when the output end of the power module is in short circuit, and the large current in the power module causes the loss of an adjusting tube in a series voltage stabilizing circuit to be increased, the heating is serious and even the adjusting tube is damaged. The invention provides a short-circuit protection circuit for the output end of a power supply module, which can completely disconnect the electric energy power supply input of the power supply module when the output end of the power supply module is in short circuit, completely stop working and avoid generating large current.
The technical scheme provided by the invention is concretely realized as follows:
a power module output short circuit protection circuit, the circuit comprising: the device comprises a serial voltage stabilizing circuit, a plurality of power supply modules, an auxiliary control circuit and a control MCU. The input end of the serial voltage stabilizing circuit is connected with an external power supply VIN, the output end of the serial voltage stabilizing circuit is connected with the input ends of the plurality of power supply modules in parallel, and the control end of the serial voltage stabilizing circuit is connected with the output end of the auxiliary control circuit. The external power source VIN provides power for the power module U1 and U2 through Q1. One of the power supply modules is connected with the control MCU through the output end of the power supply module to supply power for the control MCU, and the other power supply modules supply power to other equipment or circuits through respective output ends. The input end of the auxiliary control circuit is connected with the control pin of the control MCU, and is used for generating and outputting a software control signal at the output end of the auxiliary control circuit according to the level on the control pin, and controlling the on-off of the electrical connection between the input end and the output end of the serial voltage stabilizing circuit. When the input end of the serial voltage stabilizing circuit is connected with an external power supply VIN, the auxiliary control circuit generates and outputs a hardware opening signal with the duration of T1 at the output end of the auxiliary control circuit, and the hardware opening signal is used for opening the electrical connection between the input end and the output end of the serial voltage stabilizing circuit. The duration time T1 of the hardware turn-on signal is longer than T2, and T2 is the time required by the control MCU to complete power-on and output a software control signal with a first level at the control pin at the first time of completing power-on so as to maintain the electrical connection between the input end and the output end of the series voltage stabilizing circuit. The control MCU is used for detecting whether the output end of each power supply module is short-circuited or not, and outputting a software control signal with a second level to disconnect the electrical connection between the input end and the output end of the serial voltage stabilizing circuit when the short-circuit occurs.
Further, the series voltage stabilizing circuit comprises: the device comprises an NPN triode Q1, a voltage stabilizing diode D3, a resistor R4 and a capacitor C3. The collector of the triode Q1 is used as the input end of the serial voltage stabilizing circuit and connected with the external power supply VIN, the emitter of the triode Q1 is used as the output end of the serial voltage stabilizing circuit and connected with the power supply input ends of the plurality of power supply modules, the base of the triode Q1 is connected with one end of a resistor R4, and the other end of the resistor R4 is used as the control end of the serial voltage stabilizing circuit; a parallel branch consisting of a zener diode D3 and a capacitor C2 is connected between the base of the transistor Q1 and ground.
The auxiliary control circuit includes: resistors R1, R2, R3, R5, an NPN triode Q3, a PNP triode Q2 and a capacitor C1; the collector of the triode Q3 is connected to the input end of the series voltage stabilizing circuit through the series branch of the resistors R2 and R3, the emitter of the triode is grounded, the base of the triode Q3 is connected with one polar plate of the capacitor C1 and one end of the resistor R5, the other polar plate of the capacitor C1 is connected with the input end of the series voltage stabilizing circuit through the resistor R1, and the other end of the resistor R5 is used as the input end of the auxiliary control circuit; the base electrode of the triode Q2 is connected between the resistors R2 and R3 which are connected in series, the emitter electrode of the triode Q2 is connected with the input end of the series voltage stabilizing circuit, and the collector electrode of the triode Q2 is used as the output end and is connected with the control end of the series voltage stabilizing circuit. The time T1 may be set by adjusting the value of resistor R1 and/or capacitor C1.
Drawings
Fig. 1 is a circuit diagram of a power supply circuit of a conventional power module.
Fig. 2 is a circuit diagram of an embodiment of a power module output short-circuit protection circuit according to the present invention.
Detailed Description
Embodiments of the present invention will be described below by way of specific examples. The embodiments described in the following exemplary embodiments do not represent all embodiments of the technical solutions disclosed in the present invention. Rather, they are used only to assist those skilled in the art in understanding the nature of the invention.
Fig. 2 shows a circuit diagram of an embodiment of a power module output end short-circuit protection circuit according to the present invention. The protection circuit includes: a series voltage stabilizing circuit, power modules U1 and U2, an auxiliary control circuit and a control MCU (connected to a pin F0R _ MCU); power modules U1, U2 are LDO modules.
The series voltage stabilizing circuit comprises: the NPN triode Q1, a voltage stabilizing diode D3, a resistor R4 and a capacitor C3; the collector of the triode Q1 is used as the input end of the serial voltage stabilizing circuit and is connected with the external power supply VIN, the emitter of the triode Q1 is used as the output end of the serial voltage stabilizing circuit and is connected with the power supply input ends of the power supply modules U1 and U2, and the base of the triode Q1 is connected with one end of a resistor R4; the other end of the resistor R4 is used as the control end of the series voltage stabilizing circuit. A parallel branch consisting of a zener diode D3 and a capacitor C2 is connected between the base of the transistor Q1 and ground.
The auxiliary control circuit includes: resistors R1, R2, R3, R5, an NPN triode Q3, a PNP triode Q2 and a capacitor C1; the collector of the triode Q3 is connected to the input end of the series voltage stabilizing circuit through the series branch of the resistors R2 and R3, the emitter of the triode is grounded, the base of the triode Q3 is connected with one polar plate of the capacitor C1 and one end of the resistor R5, the other polar plate of the capacitor C1 is connected with the input end of the series voltage stabilizing circuit through the resistor R1, and the other end of the resistor R5 is used as the input end of the auxiliary control circuit; the base electrode of the triode Q2 is connected between the resistors R2 and R3 which are connected in series, the emitter electrode of the triode Q2 is connected with the input end of the series voltage stabilizing circuit, and the collector electrode of the triode Q2 is used as the output end of the series voltage stabilizing circuit and is connected with the control end of the series voltage stabilizing circuit. The diodes D1 and D2 are backflow prevention diodes, and function to prevent a backflow of current in the circuit.
The control MCU is used for detecting whether the output end of each power supply module is short-circuited or not, and outputting a control signal to the input end Enable of the auxiliary control circuit to disconnect the electrical connection between the input end and the output end of the serial voltage stabilizing circuit when the short-circuit occurs.
The working process of the short-circuit protection circuit at the output end of the power supply module in fig. 2 is as follows:
when the circuit is connected with an input voltage Vin, the base electrode and the emitter electrode of the triode Q3 are conducted, the capacitor C1 is charged through the resistor R1 and a channel between the base electrode and the emitter electrode of the triode Q3, and the charging time is T1. At this time, NPN triode Q3, a high level signal is generated at the base electrode, and Q3 is in saturated conduction; the emitter of the PNP triode Q2 is reversely biased, the collector is forwardly biased, and the triode Q2 is also in saturation conduction; an external power supply VIN generates current through a branch circuit among a triode Q2, a current-limiting resistor R4 and a grounding voltage regulator D3, and a hardware turn-on signal with the duration of T1 is generated at a collector of a triode Q2. Under the action of the hardware turn-on signal, the base electrode of the triode Q1 establishes voltage, and the value of the voltage is the regulated voltage value V of the voltage regulator tubeZ(ii) a At the moment, an emitting electrode of the triode Q1 is biased in a forward direction, and a collecting electrode of the triode Q1 is biased in a reverse direction, and the triode Q1 works in an amplification region; an external power supply VIN is prompted to supply power to the control MCU through the output end of the power supply module U1, and the control MCU starts power-on initialization; the external power source VIN also supplies power to other devices through the output of the power module U2. And generating a high-level software control signal at the first time after the control MCU completes power-on initialization and outputting the high-level software control signal to an Enable end to maintain the conduction state of the triode Q1. If T2 is the time required for the control MCU to complete power-on and output a high-level software control signal at the first time of completing power-on, the time T1 is set by setting the parameters of R1 and/or C1 as: t1>T2, to ensure the control MCU can complete power-up and work normally.
If the output end of the linear power supply U1 is short-circuited in the power-on process of the control MCU or before the power-on, the MCU does not supply power, the Enable end level is always low, the time T1 exceeds, the triodes Q3 and Q2 are cut off and switched off, the base voltage of the triodes cannot be maintained, and the Q1 is cut off and switched off to cause the U1 to be completely switched off and stop working. If the output end of the power supply module U2 is short-circuited in the power-on process of the control MCU or before the power-on, after the power-on of the control MCU is finished and the output voltage of the U2 is detected to be 0, the level of the Enable end is pulled down, after the time exceeds T1, the triodes Q3 and Q2 are cut off, and V isZThe transistor Q1 can not be maintained to be cut off, and the U2 is completely cut off and stops working.
When the control MCU works normally, whether the output ends of the power supply modules U1 and U2 are short-circuited or not is detected, and when the short-circuit occurs, a low-level control signal is output to disconnect the electrical connection between the input end and the output end of the series voltage stabilizing circuit. The method specifically comprises the following steps: when the output end of the power supply module U1 is short-circuited, the circuit worksThe output current is the current limiting value, the MCU is not powered and cannot work at the moment, the level of the Enable end is low, the triodes Q3 and Q2 are cut off, and V isZCannot be maintained, Q1 is turned off, and U1 is completely turned off. When the output end of the power supply module U2 is short-circuited, the working output current is the current limiting value, the MCU is controlled to work normally, the output voltage of the linear power supply U2 is detected to be 0, the low level is output to the Enable end, and the triodes Q3, Q2 and Q1 are cut off.
The scheme provided by the invention can completely shut down the related power supply when the output end of the power supply module generates short circuit, so that the power supply module stops working. The MCU protection circuit is not only suitable for carrying out output end short-circuit protection on different electric power modules in a starting state and a working state, but also is even suitable for the condition that the MCU detectable non-power-supply type fault needs to close the power supply.
While the invention has been described in connection with the above embodiments and implementations, the invention is not so limited but covers various obvious modifications and equivalent arrangements, which fall within the purview of the appended claims. Although features of the invention are expressed in certain combinations among the claims, it is contemplated that these features can be arranged in any combination and order.
Claims (3)
1. A power module output short circuit protection circuit, the circuit comprising: the device comprises a serial voltage stabilizing circuit, a plurality of power supply modules, an auxiliary control circuit and a control MCU (microprogrammed control unit); the serial voltage stabilizing circuit comprises an input end, an output end and a control end, wherein the input end of the serial voltage stabilizing circuit is connected with an external power supply VIN for supplying power to the power supply modules through a backflow prevention diode D1, the output end of the serial voltage stabilizing circuit is connected with the input ends of the power supply modules, and the control end of the serial voltage stabilizing circuit is connected with the output end of the auxiliary control circuit;
the series voltage stabilizing circuit specifically comprises: the NPN triode Q1, a voltage stabilizing diode D3, a resistor R4 and a capacitor C3; the collector of the triode is used as the input end of the serial voltage stabilizing circuit, the emitter of the triode is used as the output end of the serial voltage stabilizing circuit, the base of the triode is connected with one end of a resistor R4, and the other end of the resistor R4 is used as the control end of the serial voltage stabilizing circuit; a parallel branch consisting of a voltage stabilizing diode D3 and a capacitor C2 is connected between the base of the triode Q1 and the ground;
one of the power supply modules is connected with the control MCU through the output end of the power supply module to supply power for the control MCU, and the other power supply modules supply power to other equipment or circuits through respective output ends;
the input end of the auxiliary control circuit is connected with a control pin of the control MCU through a backflow prevention diode D2, and the auxiliary control circuit is used for generating and outputting a software control signal at the output end of the auxiliary control circuit according to the level on the control pin and controlling the on-off of the electrical connection between the input end and the output end of the serial voltage stabilizing circuit; when the input end of the serial voltage stabilizing circuit is connected with an external power supply VIN, the auxiliary control circuit generates and outputs a hardware opening signal with the duration of T1 at the output end of the auxiliary control circuit, and the hardware opening signal is used for opening the electrical connection between the input end and the output end of the serial voltage stabilizing circuit; the duration time T1 of the hardware turn-on signal is longer than T2, and T2 is the time required for the control MCU to complete power-on and output a software control signal with a first level at the first time of completing power-on so as to maintain the electrical connection between the input end and the output end of the series voltage stabilizing circuit;
the auxiliary control circuit includes: resistors R1, R2, R3, R5, an NPN triode Q3, a PNP triode Q2 and a capacitor C1; the collector of the triode Q3 is connected to the input end of the series voltage stabilizing circuit through the series branch of the resistors R2 and R3, the emitter of the triode is grounded, the base of the triode Q3 is connected with one polar plate of the capacitor C1 and one end of the resistor R5, the other polar plate of the capacitor C1 is connected with the input end of the series voltage stabilizing circuit through the resistor R1, and the other end of the resistor R5 is used as the input end of the auxiliary control circuit; the base electrode of the triode Q2 is connected between the resistors R2 and R3 which are connected in series, the emitter electrode of the triode Q2 is connected with the input end of the series voltage stabilizing circuit, and the collector electrode of the triode Q2 is used as the output end and is connected with the control end of the series voltage stabilizing circuit;
the input end of the serial voltage stabilizing circuit is also used for detecting whether the output end of each power supply module is short-circuited or not, and when the short circuit occurs, a second level software control signal is output to disconnect the electrical connection between the input end and the output end of the serial voltage stabilizing circuit.
2. The power module output short-circuit protection circuit as claimed in claim 1, wherein the time T1 can be set by adjusting the value of the resistor R1 and/or the capacitor C1.
3. The power module output short-circuit protection circuit of claim 1, wherein the power module is a linear power supply (LDO) module.
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CN201911239440.1A CN110994559B (en) | 2019-12-06 | 2019-12-06 | Power module output end short-circuit protection circuit |
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CN209200926U (en) * | 2018-12-26 | 2019-08-02 | 苏州易德龙科技股份有限公司 | A kind of system of self-locking software controlling power circuit on-off |
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CN101567549B (en) * | 2009-03-03 | 2012-07-04 | 四川神坤装备股份有限公司 | Direct-current safety gate |
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CN106560958A (en) * | 2016-10-20 | 2017-04-12 | 金卡高科技股份有限公司 | Low-power-consumption voltage protection circuit and gas meter |
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CN104617558A (en) * | 2013-11-01 | 2015-05-13 | 欧姆龙株式会社 | Power supply short circuit protection circuit |
CN204794007U (en) * | 2015-05-04 | 2015-11-18 | 惠州三华工业有限公司 | DC power supply circuit with short -circuit protection |
CN204595590U (en) * | 2015-05-11 | 2015-08-26 | 上海松江飞繁电子有限公司 | A kind of input/output module control circuit |
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