CN111327018A - Over-current and over-voltage self-locking protection circuit and adapter - Google Patents

Over-current and over-voltage self-locking protection circuit and adapter Download PDF

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Publication number
CN111327018A
CN111327018A CN202010232674.XA CN202010232674A CN111327018A CN 111327018 A CN111327018 A CN 111327018A CN 202010232674 A CN202010232674 A CN 202010232674A CN 111327018 A CN111327018 A CN 111327018A
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China
Prior art keywords
self
locking
resistor
locking protection
power supply
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CN202010232674.XA
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Chinese (zh)
Inventor
丘恒良
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Zhuhai Amicro Semiconductor Co Ltd
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Zhuhai Amicro Semiconductor Co Ltd
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Priority to CN202010232674.XA priority Critical patent/CN111327018A/en
Publication of CN111327018A publication Critical patent/CN111327018A/en
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    • 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
    • H02H3/08—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 excess current
    • H02H3/087—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 excess current for dc applications
    • 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
    • H02H3/02—Details
    • H02H3/05—Details with means for increasing reliability, e.g. redundancy arrangements
    • 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
    • H02H3/08—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 excess current
    • H02H3/10—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 excess current additionally responsive to some other abnormal electrical conditions
    • 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
    • H02H3/20—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 excess voltage
    • H02H3/202—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 excess voltage for dc systems
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
    • H02J7/0029—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries with safety or protection devices or circuits
    • H02J7/0031—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries with safety or protection devices or circuits using battery or load disconnect circuits

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Amplifiers (AREA)
  • Control Of Voltage And Current In General (AREA)

Abstract

The invention discloses an overcurrent and overvoltage self-locking protection circuit and an adapter, which comprise an overcurrent monitoring unit, an overvoltage monitoring unit, an output switch unit and a self-locking protection unit; the signal input end of the self-locking protection unit is connected with an external direct-current power supply, the signal output end of the output switch unit is connected with the power supply output end of the self-locking protection circuit, and the signal input end of the output switch unit is connected with the signal input end of the self-locking protection unit; the sampling input end of the over-current monitoring unit is used for sampling a current signal output by an external direct-current power supply to detect an over-current signal; the sampling input end of the overvoltage monitoring unit is connected with the power supply output end of the upper self-locking protection circuit; the feedback input end of the self-locking protection unit is simultaneously connected with the output end of the overcurrent monitoring unit and the output end of the overvoltage monitoring unit; two outputs of auto-lock protection unit are connected respectively to two inputs of output switch unit, and auto-lock protection unit passes through the auto-lock that output switch unit realized protection state, avoids appearing hiccup the electricity pumping.

Description

Over-current and over-voltage self-locking protection circuit and adapter
Technical Field
The invention belongs to the technical field of circuit protection, and particularly relates to an overcurrent and overvoltage self-locking protection circuit and an adapter.
Background
Due to various complicated power utilization environments, electronic devices are inevitably subjected to harsh working conditions exceeding the rated working conditions of the devices in the charging process or manual operation errors, and under the conditions, the electronic devices can be damaged instantly, and manual work cannot perform power-off protection on the electronic devices in a short time. If the electronic device has a problem in the charging process and does not work with a protection circuit, the service life safety of the electronic device is reduced, or the electronic device is directly damaged and burnt out, so that the loss which is difficult to estimate is caused.
In practical application, when an overcurrent protection circuit in the prior art detects that a sampling voltage signal is higher than a set value of a protection point, the overcurrent protection circuit generates protection signals and respectively outputs the protection signals to a related power supply control circuit, the power supply control circuit immediately responds to the situation that power supply of a power supply is cut off in a short time, large current disappears immediately, the protection signals of the overcurrent protection circuit disappear immediately, at the moment, the power supply control circuit can restore power supply of the power supply in a short time, charging current sharply increases immediately, and electric equipment which is still being charged repeatedly bears the impact of a hiccup power-off state and overcurrent impact.
In the prior art, the MCU is also adopted to detect the overcurrent protection circuit to generate a protection signal, but the MCU effectively detects that the protection signal needs a certain detection time, and after the protection signal of the overcurrent protection circuit disappears, the MCU cannot effectively detect the protection signal, and the MCU also increases the design cost.
Disclosure of Invention
In order to solve the technical problem, the invention discloses an overcurrent and overvoltage self-locking protection circuit which can monitor voltage and current on one hand and can self-lock the protection state of the circuit on the other hand to prevent hiccup power-off. The specific technical scheme is as follows:
a self-locking protection circuit for overcurrent and overvoltage comprises an overcurrent monitoring unit, an overvoltage monitoring unit, an output switch unit and a self-locking protection unit; the signal input end of the self-locking protection unit is connected with an external direct-current power supply, the signal output end of the output switch unit is connected with the power supply output end of the self-locking protection circuit, and the signal input end of the output switch unit is connected with the signal input end of the self-locking protection unit, wherein the signal input end of the self-locking protection unit is the power supply input end of the self-locking protection circuit; the sampling input end of the over-current monitoring unit is used for sampling a current signal output by an external direct-current power supply to detect an over-current signal, and the sampling input end of the over-voltage monitoring unit is connected with the power supply output end of the self-locking protection circuit and is used for sampling a voltage signal output by the external direct-current power supply to detect an over-voltage signal; the feedback input end of the self-locking protection unit is simultaneously connected with the output end of the overcurrent monitoring unit and the output end of the overvoltage monitoring unit and is used for acquiring overcurrent and overvoltage signals output by the overcurrent monitoring unit and/or the overvoltage monitoring unit; the two input ends of the output switch unit are respectively connected with the two output ends of the self-locking protection unit and used for controlling the on-off of a path between the power supply input end and the power supply output end of the self-locking protection circuit; the self-locking protection unit and the output switch unit are provided with a common ground end; the self-locking protection unit is used for maintaining the state that the output switch unit cuts off a passage between the power input end and the power supply output end of the self-locking protection circuit under the influence of an overcurrent and overvoltage state signal input by the feedback input end of the self-locking protection unit, so that the self-locking protection circuit is kept in a self-locking protection state.
This technical scheme utilizes the overcurrent monitoring unit, the overvoltage monitoring unit, output switch unit and auto-lock protection unit form the automatic feedback loop, the excessive pressure state signal that overflows that the feedback input end through the auto-lock protection unit gathered, the state of the passageway between the power input end that automatic control auto-lock protection unit locking output switch unit cut off the auto-lock protection circuit and the power output end, thereby the phenomenon that charges repeatedly and have a power failure appears in the influence of the hiccup extraction of the power output end that no longer receives the auto-lock protection circuit, simultaneously also need not to control the execution circuit to overflow the overvoltage protection function by MCU processing with overflowing the excessive pressure state signal, the simplified circuit structure, and low cost.
Further, under the condition that the self-locking protection circuit does not enter the self-locking protection state, a path exists between a power supply input end and a power supply output end of the self-locking protection circuit. In the technical scheme, the self-locking protection circuit can support the normal charging operation of the direct-current power supply in a normal working state.
Furthermore, the self-locking protection unit comprises a first group of voltage division resistors, a second group of voltage division resistors, a third group of voltage division resistors, a first switching PMOS tube, a second switching PMOS tube, an NPN self-locking switch triode or a self-locking switch NMOS tube; the source electrode of the second switching PMOS tube and the drain electrode of the second switching PMOS tube are two output ends of the self-locking protection unit respectively and are correspondingly connected with two input ends of the output switch unit; a common end of the first group of voltage division resistors and the second group of voltage division resistors is connected to a power input end of the self-locking protection circuit, and a source electrode of the first switching PMOS tube and a source electrode of the second switching PMOS tube are both connected to the power input end of the self-locking protection circuit; the voltage division nodes of the first group of voltage division resistors are connected with the grid electrode of the first switching PMOS tube, the voltage division nodes of the second group of voltage division resistors are connected with the grid electrode of the second switching PMOS tube, and the voltage division nodes of the third group of voltage division resistors are connected with the base electrode of the NPN self-locking switch triode or the grid electrode of the self-locking switch NMOS tube; the first group of voltage division resistors and the second group of voltage division resistors are grounded through an NPN self-locking switch triode or a self-locking switch NMOS tube; the third group of divider resistors is connected to the power input end of the self-locking protection circuit through a first switching PMOS tube; a base electrode of the NPN self-locking switch triode or a grid electrode of the NMOS tube of the self-locking switch is connected with the feedback input end of the self-locking protection unit; the self-locking protection unit is used for conducting an NPN self-locking switch triode or a self-locking switch NMOS tube when a feedback input end of the self-locking protection unit collects an overcurrent and overvoltage signal output by the overcurrent monitoring unit and/or the overvoltage monitoring unit, so that bias voltage generated by a direct-current power supply input by the self-locking protection unit at a voltage division node of a second group of voltage division resistors conducts a second switching PMOS tube, and the output switch unit is enabled to cut off a path between a power supply input end and a power supply output end of the self-locking protection circuit; meanwhile, a bias voltage generated by a direct-current power supply input by the self-locking protection unit at a voltage division node of a first group of voltage division resistors is conducted on a first switching PMOS tube, so that a bias voltage generated by the direct-current power supply input by the self-locking protection unit at a voltage division node of a third group of voltage division resistors is conducted on an NPN self-locking switch triode or a self-locking switch NMOS tube, and the NPN self-locking switch triode or the self-locking switch NMOS tube is kept in a conducting state under the influence of an overcurrent and overvoltage state signal input by a feedback input end of the self-locking protection unit, so that the self-locking protection circuit is kept in a self-locking protection; when the feedback input end of the self-locking protection unit does not acquire an overcurrent and overvoltage signal output by the overcurrent monitoring unit and/or the overvoltage monitoring unit all the time, the NPN self-locking switch triode or the self-locking switch NMOS tube is turned off, the second switching PMOS tube and the first switching PMOS tube are both cut off, and then a path is kept between the power supply input end and the power supply output end of the self-locking protection circuit.
Compared with the prior art, after the over-current and over-voltage state signals are collected by the self-locking protection unit, the PMOS tubes are conducted by using the bias voltage generated by the input direct-current power supply at one group of voltage-dividing resistors, so that the output switch unit is enabled to cut off the path between the power supply input end and the power supply output end of the self-locking protection circuit, the N-type switch tubes are maintained to be conducted by using the bias voltage generated by the input direct-current power supply at the other group of voltage-dividing resistors, the current working state of the cut-off path of the output switch unit is locked, the self-locking protection circuit is enabled to be kept in the self-locking protection state by using the conduction logic relation formed between the voltage-dividing resistors and the switch tubes, and meanwhile, the over-current or over-current protection signals are timely detected, so that protection is implemented, and the.
Further, in the self-locking protection unit, the first group of voltage-dividing resistors includes a first resistor and a second resistor which are connected in series, the second group of voltage-dividing resistors includes a third resistor and a fourth resistor which are connected in series, the third group of voltage-dividing resistors includes a fifth resistor, and the third group of voltage-dividing resistors further includes a sixth resistor and/or an eleventh resistor; one end of a first resistor is connected with the power input end of the self-locking protection circuit, the other end of the first resistor is connected with one end of a second resistor, and the other end of the second resistor is connected with the collector electrode of the NPN self-locking switch triode or the drain electrode of the self-locking switch NMOS tube, wherein the connecting node of the first resistor and the second resistor is the voltage dividing node of the first group of voltage dividing resistors, the connecting node is connected with the grid electrode of the first switching PMOS tube, and the source electrode of the first switching PMOS tube is connected with the power input end of the self-locking protection circuit; one end of a third resistor is connected with the power input end of the self-locking protection circuit, the other end of the third resistor is connected with one end of a fourth resistor, and the other end of the fourth resistor is connected with the collector electrode of the NPN self-locking switch triode or the drain electrode of the self-locking switch NMOS tube, wherein the connection node of the third resistor and the fourth resistor is the voltage division node of the second group of voltage division resistors, the connection node is connected with the grid electrode of a second switching PMOS tube, and the source electrode of the second switching PMOS tube is connected with the power input end of the self-locking protection circuit; one end of a fifth resistor is connected with a drain electrode of the first switching PMOS tube, the other end of the fifth resistor is connected with one end of a sixth resistor and/or one end of an eleventh resistor, the other end of the sixth resistor and/or the other end of the eleventh resistor are/is grounded, a connection node of the fifth resistor and the sixth resistor and/or the eleventh resistor is a voltage division node of the third group of voltage division resistors, the connection node is connected with a base electrode of the NPN self-locking switch triode or a grid electrode of the self-locking switch NMOS tube, a radiation electrode of the NPN self-locking switch triode or a source electrode of the self-locking switch NMOS tube is grounded, and a feedback input end of the self-locking protection unit is the base electrode of the NPN self-locking switch triode or the grid electrode of the self-locking switch NMOS.
Compared with the prior art, the self-locking protection unit utilizes a simple series resistance voltage division structure, a connection structure between a PMOS (P-channel metal oxide semiconductor) tube which is connected at a corresponding voltage division node and used for switching a working state and an N-type switch tube used for starting locking protection, automatically changes the conduction state of the P-type MOS tube and the conduction state of the N-type switch tube in sequence, and then maintains the conduction of the P-type MOS tube and the conduction of the N-type switch tube based on the bias voltage at the voltage division node of the series resistance voltage division structure and the circuit breaking effect of the output switch unit, so that the self-locking protection state of the self-locking protection circuit is maintained, and the repeated current impact on an electrical appliance, which is easy to occur in the traditional overcurrent.
Furthermore, the output switch unit comprises a power supply switch PMOS tube and a fourth group of voltage dividing resistors, the source electrode of the power supply switch PMOS tube is connected with the power supply input end of the self-locking protection circuit, and the drain electrode of the power supply switch PMOS tube is connected with the power supply output end of the self-locking protection circuit; a common end of the first group of voltage division resistors, the second group of voltage division resistors and the fourth group of voltage division resistors is connected to a power input end of the self-locking protection circuit, and the fourth group of voltage division resistors is grounded with an emitter of the NPN self-locking switch triode or a source of the NMOS transistor of the self-locking switch; the source electrode of the second switching PMOS tube is connected with the power supply input end of the self-locking protection circuit, the drain electrode of the second switching PMOS tube is connected with the voltage division node of the fourth group of voltage division resistors, and the voltage division node of the fourth group of voltage division resistors is connected with the grid electrode of the power supply switch PMOS tube; the output switch unit is used for increasing the bias voltage generated by a voltage dividing node of a fourth group of voltage dividing resistors by connecting the second switching PMOS tube in parallel when the second switching PMOS tube is switched on so as to cut off the power supply switch PMOS tube and further cut off a path between a power supply input end and a power supply output end of the self-locking protection circuit; the output switch unit is used for only enabling the direct-current power supply input by the self-locking protection unit to generate bias voltage at a voltage division node of the fourth group of voltage division resistors when the second switching PMOS tube is cut off so as to conduct the power supply switch PMOS tube, and further forming a passage for the output switch unit to be communicated with the power supply input end and the power supply output end of the self-locking protection circuit.
In the technical scheme, the drain-source electrode of the power supply switch PMOS transistor of the output switch unit is connected between the power input end and the output end of the self-locking protection circuit, so that the output switch unit reversely changes the conduction state of the power supply switch PMOS transistor according to the conduction state of the second switching PMOS transistor inside the self-locking protection unit, the bias voltage generated by the input direct-current power supply at the voltage division node of the voltage division resistor adapts to the over-current and over-voltage state currently detected by the self-locking protection unit, and the self-locking protection of the self-locking protection circuit is maintained by keeping the power supply switch PMOS transistor cut off.
Further, in the output switching unit, the fourth group of voltage-dividing resistors includes a seventh resistor and an eighth resistor connected in series; one end of a seventh resistor is simultaneously connected with a power input end of the self-locking protection circuit and a source electrode of the second switching PMOS tube, the other end of the seventh resistor is connected with one end of an eighth resistor, and the other end of the eighth resistor is grounded, wherein a connection node of the seventh resistor and the eighth resistor is a voltage division node of the fourth group of voltage division resistors, the connection node is simultaneously connected with a drain electrode of the second switching PMOS tube and a grid electrode of the power supply switch PMOS tube, and two ends of the seventh resistor are respectively used as two input ends of the output switch unit; and the emitter electrode of the NPN self-locking switch triode or the source electrode of the NMOS tube of the self-locking switch and the grounding end of the eighth resistor are connected with the common ground end of the self-locking protection unit and the output switch unit.
According to the technical scheme, the conducted second switching PMOS tube is connected with a divider resistor connected with the power input end of the self-locking protection circuit in parallel, so that the divided voltage value of the divider resistor is reduced, another divider resistor bears more voltage, the bias voltage of the divided voltage node of the fourth group of divider resistors is increased, the second switching PMOS tube is cut off, and the output switch unit cuts off a path between the power input end and the power supply output end of the self-locking protection circuit.
Furthermore, the overvoltage monitoring unit comprises a first diode, a first operational amplifier, a ninth resistor and a tenth resistor, wherein one end of the ninth resistor is connected with the drain electrode of the power supply switch PMOS transistor, the other end of the ninth resistor is simultaneously connected with one end of the tenth resistor and the positive input end of the first operational amplifier, the other end of the tenth resistor is grounded, and the negative input end of the first operational amplifier is connected with a reference voltage; the output end of the first operational amplifier is connected with the anode of a first diode, the cathode of the first diode is connected with the feedback input end of the self-locking protection unit, the feedback input end is used for improving the conduction threshold of the NPN self-locking switch triode or the self-locking switch NMOS tube, and the output current of the over-current monitoring unit is prevented from flowing backwards by utilizing the unidirectional conductivity of the diode; the connection node of the ninth resistor and the tenth resistor is used for acquiring a sampling voltage signal of a power supply output end of the self-locking protection circuit, and the sampling voltage signal is compared with a reference voltage by the first operational amplifier, so that the output end of the first operational amplifier outputs a voltage signal reflecting an overvoltage state.
Furthermore, the over-current monitoring unit includes a second diode, a second operational amplifier, a twelfth resistor, a thirteenth resistor and a fourteenth resistor, a positive input end of the second operational amplifier is a sampling end of the over-current monitoring unit, one end of the twelfth resistor is connected to the positive input end of the second operational amplifier, and the other end of the twelfth resistor is grounded and used for sampling and acquiring a current signal of a power supply output end of the self-locking protection circuit, wherein a sampling input end of the over-current monitoring unit is the positive input end of the second operational amplifier; the negative input end of the second operational amplifier is connected with one end of a fourteenth resistor, and the other end of the fourteenth resistor is grounded; one end of the thirteenth resistor is connected with the negative input end of the second operational amplifier, the other end of the thirteenth resistor is connected with the output end of the second operational amplifier, and the output end of the second operational amplifier is used for detecting whether the current signal sampled by the twelfth resistor is overcurrent or not; the output end of the second operational amplifier is connected with the anode of a second diode, the cathode of the second diode is connected with the feedback input end of the self-locking protection unit, the feedback input end of the self-locking protection unit is used for improving the conduction threshold of the NPN self-locking switch triode or the self-locking switch NMOS tube, and the output current of the overvoltage monitoring unit is prevented from flowing backwards by utilizing the unidirectional conductivity of the diode.
Further, the first switching PMOS tube, the second switching PMOS tube and the power supply switch PMOS tube are enhancement type PMOS tubes. Based on the conduction threshold characteristic of the enhanced PMOS tube, the normal maintenance of the self-locking protection working state of the output switch unit and the self-locking protection unit can be ensured by adopting a source end power supply structure of the enhanced PMOS tube, wherein the first switching PMOS tube, the second switching PMOS tube and the power supply switch PMOS tube are arranged in the self-locking protection circuit.
The adapter comprises the self-locking protection circuit, wherein electrical equipment is connected between a power supply output end of the self-locking protection circuit and a sampling input end of an overcurrent monitoring unit in the self-locking protection circuit and used for charging the electrical equipment, and a charging power supply of the adapter is from a direct current power supply input by a signal input end of the self-locking protection circuit. This adapter simultaneously control charging voltage electric current to after detecting overcurrent overvoltage signal, get into the auto-lock protection state immediately, prevent the hiccup and draw electricity.
Drawings
Fig. 1 is a schematic view of an application scenario of a self-locking protection circuit for overcurrent and overvoltage according to an embodiment of the present invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be described in detail below with reference to the accompanying drawings in the embodiments of the present invention. It is noted that relational terms such as "first" and "second," and the like, may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.
The invention discloses an overcurrent and overvoltage self-locking protection circuit, which comprises an overcurrent monitoring unit, an overvoltage monitoring unit, an output switch unit and a self-locking protection unit, wherein the signal input end of the self-locking protection unit is connected with an external direct-current power supply, and the signal output end of the output switch unit is connected with the power supply output end of the self-locking protection circuit; the sampling input end of the over-current monitoring unit is used for sampling a current signal output by an external direct-current power supply, detecting the over-current signal by sampling the current signal output to electrical equipment and charging equipment, and feeding back a signal to the self-locking protection unit when the over-current signal is detected; the sampling input end of the overvoltage monitoring unit is connected with the power supply output end of the self-locking protection circuit, and is used for sampling a voltage signal output by an external direct-current power supply to detect an overvoltage signal and feeding the overvoltage signal back to the self-locking protection unit; the feedback input end of the self-locking protection unit is simultaneously connected with the output end of the overcurrent monitoring unit and the output end of the overvoltage monitoring unit and is used for acquiring overcurrent and overvoltage state information output by the overcurrent monitoring unit and/or the overvoltage monitoring unit, and the overcurrent and overvoltage state information can trigger the level state in the self-locking protection unit to change and maintain the level in the self-locking state; the self-locking protection unit and the output switch unit have a common ground end, two input ends of the output switch unit are respectively connected with two corresponding output ends of the self-locking protection unit, is used for controlling the on-off of a path between the power supply input end and the power supply output end of the self-locking protection circuit, after the self-locking protection unit enters a self-locking protection state, the output switch unit cuts off the path between the power input end and the power supply output end of the self-locking protection circuit, the self-locking protection circuit can recover the normal working state only after the power input end of the self-locking protection circuit stops supplying power, therefore, the self-locking protection unit is used for maintaining the state that the output switch unit cuts off the passage between the power supply input end and the power supply output end of the self-locking protection circuit under the influence of the overcurrent and overvoltage state signal input by the feedback input end of the self-locking protection unit, so that the self-locking protection circuit is kept in the self-locking protection state. This embodiment utilizes the overcurrent monitoring unit, overvoltage monitoring unit, output switch unit and auto-lock protection unit form the automatic feedback loop, the excessive pressure state signal that overflows that the feedback input end through the auto-lock protection unit gathered, the state of the route between the power input end that cuts off the auto-lock protection circuit of auto-control auto-lock protection unit locking output switch unit and the power output end, thereby the phenomenon that charges repeatedly and have a power failure appears in the influence of the hiccup extraction of the power output end that no longer receives the auto-lock protection circuit, simultaneously also need not handle the excessive pressure state signal that overflows and come control execution circuit overcurrent overvoltage protection function by MCU, the simplified circuit structure, and low cost.
It should be noted that, in a normal operating state, the output switch unit maintains a path between the power input terminal and the power supply output terminal of the self-locking protection circuit, that is, a path exists between the power input terminal and the power supply output terminal of the self-locking protection circuit when the self-locking protection circuit does not enter the self-locking protection state. The self-locking protection circuit can support the normal charging operation of the direct-current power supply in a normal working state.
As an embodiment, the self-locking protection unit includes a first group of voltage dividing resistors, a second group of voltage dividing resistors, a third group of voltage dividing resistors, a first switching PMOS transistor, a second switching PMOS transistor, and an NPN self-locking switch triode or a self-locking switch NMOS transistor; the source electrode of the second switching PMOS tube and the drain electrode of the second switching PMOS tube are two output ends of the self-locking protection unit respectively and are correspondingly connected with two input ends of the output switch unit, and the on and off of the second switching PMOS tube can bring influence to the level change in the output switch unit. And a common end of the first group of voltage division resistors and the second group of voltage division resistors is connected to a power supply input end of the self-locking protection circuit. The source electrode of the first switching PMOS tube and the source electrode of the second switching PMOS tube are both connected to the power input end of the self-locking protection circuit, and the source electrode of the first switching PMOS tube and the source electrode of the second switching PMOS tube are both PMOS tubes; if the NMOS tube is used instead, the grid electrode of the NMOS tube as the switch control end cannot be directly connected to the power input end of the self-locking protection circuit to ensure the conduction of the control NMOS tube, so that only the PMOS tube can be selected to execute the function of the change-over switch, and the PMOS tube is set as a source end power supply structure. The voltage division nodes of the first group of voltage division resistors are connected with the grid electrode of the first switching PMOS tube, the voltage division nodes of the second group of voltage division resistors are connected with the grid electrode of the second switching PMOS tube, and the voltage division nodes of the third group of voltage division resistors are connected with the base electrode of the NPN self-locking switch triode or the grid electrode of the self-locking switch NMOS tube; the first group of voltage division resistors and the second group of voltage division resistors are grounded through an NPN self-locking switch triode or a self-locking switch NMOS tube, when the NPN self-locking switch triode or the self-locking switch NMOS tube is conducted and then the first switching PMOS tube and the second switching PMOS tube are conducted, power voltage input by the self-locking protection circuit is divided into the first group of voltage division resistors and the second group of voltage division resistors respectively, voltage division nodes of the first group of voltage division resistors generate first bias voltage, and meanwhile voltage division nodes of the second group of voltage division resistors generate second bias voltage. The third group of divider resistors is connected to the power input end of the self-locking protection circuit through a first switching PMOS tube; a base electrode of the NPN self-locking switch triode or a grid electrode of the NMOS tube of the self-locking switch is connected with the feedback input end of the self-locking protection unit; the self-locking protection unit is used for conducting an NPN self-locking switch triode or a self-locking switch NMOS tube when a feedback input end of the self-locking protection unit collects an overcurrent and overvoltage state signal output by the overcurrent monitoring unit and/or the overvoltage monitoring unit, so that bias voltage generated by a direct-current power supply input by the self-locking protection unit at a voltage division node of a second group of voltage division resistors conducts a second switching PMOS tube, and the output switch unit is enabled to cut off a path between a power supply input end and a power supply output end of the self-locking protection circuit; meanwhile, a bias voltage generated by a direct-current power supply input by the self-locking protection unit at a voltage division node of the first group of voltage division resistors is conducted on the first switching PMOS tube, so that a bias voltage generated by the direct-current power supply input by the self-locking protection unit at a voltage division node of the third group of voltage division resistors is conducted on an NPN self-locking switch triode or a self-locking switch NMOS tube, and the NPN self-locking switch triode or the self-locking switch NMOS tube is kept in a conducting state under the influence of an overcurrent and overvoltage state signal input by a feedback input end of the self-locking protection unit, so that the self-locking protection circuit is kept in a self-locking protection. It is worth noting that when the feedback input end of the self-locking protection unit does not acquire the over-current and over-voltage state signals output by the over-current monitoring unit and/or the over-voltage monitoring unit all the time, the NPN self-locking switch triode or the self-locking switch NMOS tube is turned off, the second switching PMOS tube and the first switching PMOS tube are both cut off, and then a path is kept between the power supply input end and the power supply output end of the self-locking protection circuit. Compared with the prior art, after the over-current and over-voltage state signals are collected by the self-locking protection unit, the PMOS tubes are conducted by using the bias voltage generated by the input direct-current power supply at one group of voltage-dividing resistors, so that the output switch unit is enabled to cut off the path between the power supply input end and the power supply output end of the self-locking protection circuit, the N-type switch tubes are maintained to be conducted by using the bias voltage generated by the input direct-current power supply at the other group of voltage-dividing resistors, the current working state of the cut-off path of the output switch unit is locked, the self-locking protection circuit is enabled to be kept in the self-locking protection state by using the conduction logic relation formed between the voltage-dividing resistors and the switch tubes, and meanwhile, the over-current or over-current protection signals are timely detected, so that protection is implemented, and the.
In the above embodiment, the first group of voltage-dividing resistors, the second group of voltage-dividing resistors, and the third group of voltage-dividing resistors may be composed of a plurality of series resistors, or may be composed of a plurality of series-parallel resistors, but they all need to satisfy: there is a voltage divider node.
As an embodiment, as shown in fig. 1, in the self-locking protection unit, the first group of voltage-dividing resistors includes a first resistor R1 and a second resistor R2 connected in series, the second group of voltage-dividing resistors includes a third resistor R3 and a fourth resistor R4 connected in series, the third group of voltage-dividing resistors includes a fifth resistor R5, and the third group of voltage-dividing resistors further includes a sixth resistor R6 and/or an eleventh resistor R11 (the eleventh resistor R11 may be optional, and the eleventh resistor R11 exists in this embodiment); one end of a first resistor R1 is connected with a power input end VIN of the self-locking protection circuit, the other end of the first resistor R1 is connected with one end of a second resistor R2, the other end of the second resistor R2 is connected with a collector of the NPN self-locking switch triode Q1, wherein a connection node of the first resistor R1 and the second resistor R2 is a voltage division node of the first group of voltage division resistors, the connection node is connected with a grid electrode of a first switching PMOS tube MP1, and a source electrode of the first switching PMOS tube MP1 is connected with the power input end VIN of the self-locking protection circuit; one end of a third resistor R3 is connected with a power input end VIN of the self-locking protection circuit, the other end of the third resistor R3 is connected with one end of a fourth resistor R4, the other end of the fourth resistor R4 is connected with a collector of the NPN self-locking switch triode Q1, wherein a connection node of the third resistor R3 and the fourth resistor R4 is a voltage division node of the second group of voltage division resistors, the connection node is connected with a grid electrode of a second switching PMOS tube MP2, and a source electrode of the second switching PMOS tube MP2 is connected with the power input end VIN of the self-locking protection circuit; one end of a fifth resistor R5 is connected with the drain of the first switching PMOS tube MP1, the other end of a fifth resistor R5 is connected with one end of a sixth resistor R6 and one end of an eleventh resistor R11, the other end of the sixth resistor R6 and the other end of the eleventh resistor R11 are grounded, wherein the connection nodes of the fifth resistor R5, the sixth resistor R6 and the eleventh resistor R11 are voltage division nodes of the third group of voltage division resistors, the connection nodes are connected with the base electrode of the NPN self-locking switch triode Q1, the emitter electrode of the NPN self-locking switch triode Q1 is grounded, and the feedback input end of the self-locking protection unit is the base electrode of the NPN self-locking switch triode or the grid electrode of the self-locking switch NMOS tube. The self-locking protection unit utilizes a simple series resistance voltage division structure, a connection structure between a PMOS tube used for switching a working state and an N-type switch tube used for starting locking protection, which are connected at corresponding voltage division nodes, to automatically change the conduction state of the P-type MOS tube and the conduction state of the N-type switch tube in sequence, and then maintains the conduction of the P-type MOS tube and the conduction of the N-type switch tube based on the bias voltage at the voltage division nodes of the series resistance voltage division structure and the circuit breaking effect of the output switch unit, so that the self-locking protection state of the self-locking protection circuit is maintained, and the repeated current impact on an electrical appliance, which is easily caused by the traditional overcurrent protection circuit, is avoided.
As an embodiment, the output switch unit includes a power supply switch PMOS transistor and a fourth group of voltage dividing resistors, a source of the power supply switch PMOS transistor is connected to a power input terminal of the self-locking protection circuit, and a drain of the power supply switch PMOS transistor is connected to a power output terminal of the self-locking protection circuit; a common end of the first group of voltage division resistors, the second group of voltage division resistors and the fourth group of voltage division resistors is connected to a power input end of the self-locking protection circuit, and the fourth group of voltage division resistors is grounded with an emitter of the NPN self-locking switch triode or a source of the NMOS transistor of the self-locking switch; the source electrode of the second switching PMOS tube is connected with the power input end of the self-locking protection circuit, the drain electrode of the second switching PMOS tube is connected with the voltage division node of the fourth group of voltage division resistors, and the voltage division node of the fourth group of voltage division resistors is connected with the grid electrode of the power supply switch PMOS tube. In this embodiment, the gate voltage of the PMOS transistor of the power supply switch may not be greater than the voltage of the power input terminal of the self-locking protection circuit, because the power voltage input by the self-locking protection circuit is the largest, if the PMOS transistor of the power supply switch is replaced with an NMOS transistor, the gate of the NMOS transistor as the switch control terminal cannot be directly connected to the power input terminal of the self-locking protection circuit to ensure the conduction of the NMOS transistor, so that only the PMOS transistor can be selected to perform the function of the switch, and the PMOS transistor is set as the source terminal power supply structure. The output switch unit is used for increasing bias voltage generated by a voltage dividing node of a fourth group of voltage dividing resistors by connecting the second switching PMOS tube in parallel after the self-locking protection circuit enters a self-locking protection state when the second switching PMOS tube is switched on, so as to cut off the power supply switch PMOS tube, and further cut off a path between a power supply input end and a power supply output end of the self-locking protection circuit by the output switch unit; the output switch unit is used for only enabling the direct-current power supply input by the self-locking protection unit to generate bias voltage at a voltage division node of the fourth group of voltage division resistors when the second switching PMOS tube is cut off and possibly in a normal power supply charging state so as to conduct the power supply switch PMOS tube, and further forming a path for communicating the output switch unit with the power supply input end and the power supply output end of the self-locking protection circuit. In this embodiment, since the drain-source electrode of the power supply switch PMOS transistor of the output switch unit is connected between the power input end and the output end of the self-locking protection circuit, the output switch unit reversely changes the conduction state of the power supply switch PMOS transistor thereof according to the conduction state of the second switching PMOS transistor inside the self-locking protection unit, so that the bias voltage generated by the input dc power supply at the voltage division node of the voltage division resistor adapts to the current over-current and over-voltage state detected by the self-locking protection unit, and the self-locking protection of the self-locking protection circuit is maintained by keeping the power supply switch PMOS transistor turned off.
As an example, as shown in fig. 1, in the output switching unit, the fourth set of voltage-dividing resistors includes a seventh resistor R7 and an eighth resistor R8 connected in series; one end of a seventh resistor R7 is connected to the power input terminal VIN of the self-locking protection circuit and the source of the second switching PMOS transistor MP2, the other end of the seventh resistor R7 is connected to one end of an eighth resistor R8, and the other end of the eighth resistor R8 is grounded, where a connection node between the seventh resistor R7 and the eighth resistor R8 is a voltage-dividing node of the fourth group of voltage-dividing resistors, the connection node is connected to the drain of the second switching PMOS transistor MP2 and the gate of the power supply switch PMOS transistor MP3, and two ends of the seventh resistor R7 are used as two input ends of the output switch unit, respectively; a connection node between the NPN self-locking switching transistor Q1 and a ground terminal of the eighth resistor R8 is a common ground terminal existing between the self-locking protection unit and the output switching unit. In this embodiment, the turned-on second switching PMOS transistor MP2 is connected in parallel with a voltage dividing resistor R7 connected to the power input terminal VIN of the self-locking protection circuit, so as to reduce the voltage dividing value at two ends of the seventh resistor R7, and make the eighth resistor R8 bear more voltage, and the voltage at the connection node of the seventh resistor R7 and the eighth resistor R8 is increased to a voltage close to the VIN terminal, thereby turning off the second switching PMOS transistor MP2, and realizing that the output switch unit cuts off the path between the power input terminal VIN and the power output terminal VOUT of the self-locking protection circuit.
Based on the foregoing embodiment, the signal trend principle of the self-locking protection circuit in various states is as follows: under a normal working state, the NPN self-locking switch triode Q1 is not switched on, the self-locking protection unit does not introduce a direct-current power supply for voltage division, so that the first switching PMOS transistor MP1 and the second switching PMOS transistor MP2 work in a cut-off state, and the output switch unit introduces a direct-current power supply for voltage division, so that the power supply switch PMOS transistor MP3 is switched on due to voltage division of the resistors R7 and R8, and voltage is output to a power supply output terminal VOUT of the self-locking protection circuit; when the self-locking protection unit acquires an overcurrent and overvoltage signal output by the overcurrent monitoring unit and/or the overvoltage monitoring unit at the feedback input end of the self-locking protection unit, the NPN self-locking switch triode Q1 is conducted, a direct-current power supply is introduced to divide the voltage of the resistors R3 and R4, a second bias voltage is generated on a voltage division node of the resistors R3 and R4 and is enough to conduct the second switching PMOS tube MP2, then an equivalent resistor formed after the second switching PMOS tube MP2 is conducted is connected with the resistor R7 in parallel, the voltage is divided with the resistor R8, the voltage of a connection node of the resistor R7 and the resistor R8 is increased, so that the power supply switch PMOS tube MP3 works in a cut-off state, and a passage between the VIN end; meanwhile, R1 and R2 divide voltage to generate a first bias voltage on a voltage dividing node of R1 and R2, which is enough to turn on the first switching PMOS transistor MP1, and further introduce a direct current power supply to divide the voltage of R5 and R6 to form a third bias voltage on the voltage dividing node, turn on the NPN self-locking switching triode Q1, and enter a protection state, at this time, no matter whether the self-locking protection unit collects an overcurrent and overvoltage signal at a feedback input end of the self-locking protection unit, the voltage dividing node of R5 and R6 keeps the generated third bias voltage, lock the conduction working state of the NPN self-locking switching triode Q1 to form a self-locking protection state, and the normal working state can be recovered unless the power supply input end VIN of the self-locking protection circuit stops supplying power.
As shown in fig. 1, the overvoltage monitoring unit includes a first diode D1, a first operational amplifier U1, a ninth resistor R9 and a tenth resistor R10, one end of the ninth resistor R9 is connected to the drain of the power supply switch PMOS transistor MP3, the other end of the ninth resistor R9 is connected to one end of the tenth resistor R10 and the positive input end of the first operational amplifier U1, the other end of the tenth resistor R10 is grounded, and the negative input end of the first operational amplifier U1 is connected to a reference voltage VREF; the output end of the first operational amplifier U1 is connected with the anode of a first diode D1, and the cathode of the first diode D1 is connected with the feedback input end of the self-locking protection unit; the connection node of the ninth resistor R9 and the tenth resistor R10 is configured to obtain a sampled voltage signal of a power supply output terminal VOUT of the self-locking protection circuit, where the sampled voltage signal is a voltage division value of the power supply output terminal VOUT, and the first operational amplifier U1 compares the sampled voltage signal with a reference voltage VREF, so that the output terminal of the first operational amplifier U1 outputs a voltage signal reflecting an overvoltage state. When the sampling voltage signal is greater than the reference voltage VREF, the first operational amplifier U1 outputs an overvoltage signal after amplification processing, the first diode D1 is turned on, then the overvoltage signal is automatically fed back to the self-locking protection unit, and the path between the power input end and the power supply output end of the self-locking protection circuit is cut off through the output switch unit. Because the first diode D1 has a turn-on voltage, and the emitter electrode of the NPN self-locking switch triode Q1 is grounded, the output voltage of the first operational amplifier U1 needs to be higher than the turn-on control voltage of the NPN self-locking switch triode Q1 to turn on the Q1, so that the self-locking protection circuit enters the self-locking protection state, thereby improving the turn-on threshold of the NPN self-locking switch triode or the self-locking switch NMOS transistor, preventing an interference signal from being triggered by mistake to enter the self-locking protection state, and also realizing a stable sampling detection effect; on the other hand, the cathode of the first diode D1 is also connected to the output end of the over-current monitoring unit, and based on the one-way conductivity of the first diode D1, the first diode D1 can prevent the current signal output by the over-current monitoring unit from flowing back to the over-voltage monitoring unit, so that the over-current monitoring unit and the over-voltage monitoring unit can operate independently.
As shown in fig. 1, the overcurrent monitoring unit includes a second diode D2, a second operational amplifier U2, a twelfth resistor R12, a thirteenth resistor R13, and a fourteenth resistor R14, a positive input terminal + of the second operational amplifier U2 is a sampling terminal of the overcurrent monitoring unit, one end of the twelfth resistor R12 is connected to the positive input terminal of the second operational amplifier U2, and the other end of the twelfth resistor R12 is grounded, so as to sample and obtain a current signal of the power supply output terminal VOUT of the self-locking protection circuit, where the current signal condition is reflected by a voltage of a sampling terminal sample on a twelfth resistor R12 and amplified and operated by the second operational amplifier U2, where the sampling input terminal of the overcurrent monitoring unit is the positive input terminal + of the second operational amplifier U2; a negative input end of the second operational amplifier U2 is connected with one end of a fourteenth resistor R14, and the other end of the fourteenth resistor R14 is grounded; one end of a thirteenth resistor R13 is connected with the negative input end of the second operational amplifier U2, the other end of the thirteenth resistor R13 is connected with the output end of the second operational amplifier U2 to form a subtracter, the output end of the second operational amplifier U2 outputs the subtraction result of the positive end and the negative end of the second operational amplifier U2, and the negative input end of the second operational amplifier U2 is grounded through a resistor, so that the output voltage of the second operational amplifier U2 is in direct proportion to the sampling input voltage of the over-current monitoring unit according to the operational formula of the subtraction operator, and the current monitoring unit can be used for detecting whether the current signal sampled by the twelfth resistor R12 is over-current or not; the output end of the second operational amplifier U2 is connected with the anode of a second diode D2, the cathode of the second diode D2 is connected with the feedback input end of the self-locking protection unit, and the cathode of the second diode D2 is also connected with the cathode of a first diode D1 of the overvoltage monitoring unit. When the current signal sampled by the twelfth resistor R12 is detected to be overcurrent, the voltage of the output end of the second operational amplifier U2 is connected with the second diode D2, meanwhile, the overcurrent signal is automatically fed back to the self-locking protection unit, and the passage between the power supply input end and the power supply output end of the self-locking protection circuit is cut off through the output switch unit. Because the second diode D2 has a conduction voltage, and the emitter electrode of the NPN self-locking switch triode Q1 is grounded, the output voltage of the second operational amplifier U2 needs to be higher than the conduction threshold voltage of the NPN self-locking switch triode Q1 by a diode forward conduction voltage to conduct the NPN 1, so that the self-locking protection circuit enters the self-locking protection state, thereby improving the conduction threshold of the NPN self-locking switch triode or the self-locking switch NMOS transistor, preventing an interference signal from being triggered by mistake to enter the self-locking protection state, and also realizing a stable sampling detection effect; on the other hand, based on the one-way conductivity of the second diode D2, the second diode D2 can prevent the current signal output by the overvoltage monitoring unit from flowing back to the overcurrent monitoring unit, so as to ensure that the overcurrent monitoring unit and the overvoltage monitoring unit operate independently.
It is noted that the first switching PMOS transistor, the second switching PMOS transistor and the power supply switch PMOS transistor are enhancement PMOS transistors. Based on the conduction threshold characteristic of the enhanced PMOS tube, the first switching PMOS tube, the second switching PMOS tube and the power supply switch PMOS tube of the enhanced PMOS tube are adopted to form a source end power supply structure in the self-locking protection circuit, particularly in the self-locking protection circuit, the source electrodes of the first switching PMOS tube, the second switching PMOS tube and the power supply switch PMOS tube are connected to the power supply input end of the self-locking protection circuit, so as to directly receive the direct current power supply input from the outside, and make the source electrode larger than the grid electrode to form a source end power supply structure, which can ensure the normal maintenance of the self-locking protection working state of the output switch unit and the self-locking protection unit, wherein the threshold voltage of the PMOS tubes is less than 0V to be conducted, which accords with the conduction threshold characteristic of the enhanced PMOS tube, the threshold voltage of the depletion type PMOS transistor is greater than 0V, which is not suitable for turning on the aforementioned PMOS transistor under the condition of the source terminal power supply structure. Therefore, the power supply structure of the first switching PMOS tube, the second switching PMOS tube and the power supply switch PMOS tube of the enhanced PMOS tube at the source end of the self-locking protection circuit can be normally switched on and switched off, so that the normal maintenance of the self-locking protection working state of the output switch unit and the self-locking protection unit is ensured.
The invention also provides an adapter which comprises the self-locking protection circuit, wherein electrical equipment is connected between the power supply output end of the self-locking protection circuit and the sampling input end of the overcurrent monitoring unit in the self-locking protection circuit and is used for supplying power to the electrical equipment, and the power supply of the adapter is from the direct current power supply input by the signal input end of the self-locking protection circuit. This adapter simultaneously control charging voltage electric current to after detecting overcurrent overvoltage signal, get into the auto-lock protection state immediately, prevent the hiccup and draw electricity.
Finally, it should be noted that: the above examples are only intended to illustrate the technical solution of the present invention and not to limit it; although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art will understand that: modifications to the specific embodiments of the invention or equivalent substitutions for parts of the technical features may be made; without departing from the spirit of the present invention, it is intended to cover all aspects of the invention as defined by the appended claims.

Claims (10)

1. A self-locking protection circuit for overcurrent and overvoltage is characterized by comprising an overcurrent monitoring unit, an overvoltage monitoring unit, an output switch unit and a self-locking protection unit;
the signal input end of the self-locking protection unit is connected with an external direct-current power supply, the signal output end of the output switch unit is connected with the power supply output end of the self-locking protection circuit, and the signal input end of the output switch unit is connected with the signal input end of the self-locking protection unit, wherein the signal input end of the self-locking protection unit is the power supply input end of the self-locking protection circuit;
the sampling input end of the overvoltage monitoring unit is connected with the power supply output end of the upper self-locking protection circuit; the feedback input end of the self-locking protection unit is simultaneously connected with the output end of the overcurrent monitoring unit and the output end of the overvoltage monitoring unit and is used for acquiring overcurrent and overvoltage signals output by the overcurrent monitoring unit and/or the overvoltage monitoring unit;
two input ends of the output switch unit are respectively connected with two corresponding output ends of the self-locking protection unit and are used for controlling the on-off of a path between a power supply input end and a power supply output end of the self-locking protection circuit; the self-locking protection unit and the output switch unit are provided with a common ground end;
the self-locking protection unit is used for maintaining the state that the output switch unit cuts off a passage between the power input end and the power supply output end of the self-locking protection circuit under the influence of an overcurrent and overvoltage state signal input by the feedback input end of the self-locking protection unit, so that the self-locking protection circuit is kept in a self-locking protection state.
2. The self-locking protection circuit of claim 1, wherein a path exists between a power input and a power output of the self-locking protection circuit when the self-locking protection circuit does not enter the self-locking protection state.
3. The self-locking protection circuit according to claim 1 or 2, wherein the self-locking protection unit comprises a first group of voltage dividing resistors, a second group of voltage dividing resistors, a third group of voltage dividing resistors, a first switching PMOS tube, a second switching PMOS tube, an NPN self-locking switch triode or a self-locking switch NMOS tube;
the source electrode of the second switching PMOS tube and the drain electrode of the second switching PMOS tube are two output ends of the self-locking protection unit respectively and are correspondingly connected with two input ends of the output switch unit;
a common end of the first group of voltage division resistors and the second group of voltage division resistors is connected to a power input end of the self-locking protection circuit, and a source electrode of the first switching PMOS tube and a source electrode of the second switching PMOS tube are both connected to the power input end of the self-locking protection circuit; the voltage division nodes of the first group of voltage division resistors are connected with the grid electrode of the first switching PMOS tube, the voltage division nodes of the second group of voltage division resistors are connected with the grid electrode of the second switching PMOS tube, and the voltage division nodes of the third group of voltage division resistors are connected with the base electrode of the NPN self-locking switch triode or the grid electrode of the self-locking switch NMOS tube; the first group of voltage division resistors and the second group of voltage division resistors are grounded through an NPN self-locking switch triode or a self-locking switch NMOS tube; the third group of divider resistors is connected to the power input end of the self-locking protection circuit through a first switching PMOS tube; a base electrode of the NPN self-locking switch triode or a grid electrode of the NMOS tube of the self-locking switch is connected with the feedback input end of the self-locking protection unit;
the self-locking protection unit is used for conducting an NPN self-locking switch triode or a self-locking switch NMOS tube when a feedback input end of the self-locking protection unit collects an overcurrent and overvoltage signal output by the overcurrent monitoring unit and/or the overvoltage monitoring unit, so that bias voltage generated by a direct-current power supply input by the self-locking protection unit at a voltage division node of a second group of voltage division resistors conducts a second switching PMOS tube, and the output switch unit is enabled to cut off a path between a power supply input end and a power supply output end of the self-locking protection circuit; meanwhile, a bias voltage generated by a direct-current power supply input by the self-locking protection unit at a voltage division node of a first group of voltage division resistors is conducted on a first switching PMOS tube, so that a bias voltage generated by the direct-current power supply input by the self-locking protection unit at a voltage division node of a third group of voltage division resistors is conducted on an NPN self-locking switch triode or a self-locking switch NMOS tube, and the NPN self-locking switch triode or the self-locking switch NMOS tube is kept in a conducting state under the influence of an overcurrent and overvoltage state signal input by a feedback input end of the self-locking protection unit, so that the self-locking protection circuit is kept in a self-locking protection;
when the feedback input end of the self-locking protection unit does not acquire an overcurrent and overvoltage signal output by the overcurrent monitoring unit and/or the overvoltage monitoring unit all the time, the NPN self-locking switch triode or the self-locking switch NMOS tube is turned off, the second switching PMOS tube and the first switching PMOS tube are both cut off, and then a path is kept between the power supply input end and the power supply output end of the self-locking protection circuit.
4. The self-locking protection circuit according to claim 3, wherein in the self-locking protection unit, the first group of voltage-dividing resistors comprises a first resistor and a second resistor which are connected in series, the second group of voltage-dividing resistors comprises a third resistor and a fourth resistor which are connected in series, the third group of voltage-dividing resistors comprises a fifth resistor, and the third group of voltage-dividing resistors further comprises a sixth resistor and/or an eleventh resistor;
one end of a first resistor is connected with the power input end of the self-locking protection circuit, the other end of the first resistor is connected with one end of a second resistor, and the other end of the second resistor is connected with the collector electrode of the NPN self-locking switch triode or the drain electrode of the self-locking switch NMOS tube, wherein the connecting node of the first resistor and the second resistor is the voltage dividing node of the first group of voltage dividing resistors, the connecting node is connected with the grid electrode of the first switching PMOS tube, and the source electrode of the first switching PMOS tube is connected with the power input end of the self-locking protection circuit;
one end of a third resistor is connected with the power input end of the self-locking protection circuit, the other end of the third resistor is connected with one end of a fourth resistor, and the other end of the fourth resistor is connected with the collector electrode of the NPN self-locking switch triode or the drain electrode of the self-locking switch NMOS tube, wherein the connection node of the third resistor and the fourth resistor is the voltage division node of the second group of voltage division resistors, the connection node is connected with the grid electrode of a second switching PMOS tube, and the source electrode of the second switching PMOS tube is connected with the power input end of the self-locking protection circuit;
one end of a fifth resistor is connected with a drain electrode of the first switching PMOS tube, the other end of the fifth resistor is connected with one end of a sixth resistor and/or one end of an eleventh resistor, the other end of the sixth resistor and/or the other end of the eleventh resistor are/is grounded, a connection node of the fifth resistor and the sixth resistor and/or the eleventh resistor is a voltage division node of the third group of voltage division resistors, the connection node is connected with a base electrode of the NPN self-locking switch triode or a grid electrode of the self-locking switch NMOS tube, a radiation electrode of the NPN self-locking switch triode or a source electrode of the self-locking switch NMOS tube is grounded, and a feedback input end of the self-locking protection unit is the base electrode of the NPN self-locking switch triode or the grid electrode of the self-locking switch NMOS.
5. The self-locking protection circuit of claim 4, wherein the output switch unit comprises a power supply switch PMOS tube and a fourth group of voltage dividing resistors, a source electrode of the power supply switch PMOS tube is connected with a power supply input end of the self-locking protection circuit, and a drain electrode of the power supply switch PMOS tube is connected with a power supply output end of the self-locking protection circuit;
a common end of the first group of voltage division resistors, the second group of voltage division resistors and the fourth group of voltage division resistors is connected to a power input end of the self-locking protection circuit, and the fourth group of voltage division resistors is grounded with an emitter of the NPN self-locking switch triode or a source of the NMOS transistor of the self-locking switch;
the source electrode of the second switching PMOS tube is connected with the power supply input end of the self-locking protection circuit, the drain electrode of the second switching PMOS tube is connected with the voltage division node of the fourth group of voltage division resistors, and the voltage division node of the fourth group of voltage division resistors is connected with the grid electrode of the power supply switch PMOS tube;
the output switch unit is used for increasing the bias voltage generated by a voltage dividing node of a fourth group of voltage dividing resistors by connecting the second switching PMOS tube in parallel when the second switching PMOS tube is switched on so as to cut off the power supply switch PMOS tube and further cut off a path between a power supply input end and a power supply output end of the self-locking protection circuit;
the output switch unit is used for only enabling the direct-current power supply input by the self-locking protection unit to generate bias voltage at a voltage division node of the fourth group of voltage division resistors when the second switching PMOS tube is cut off so as to conduct the power supply switch PMOS tube, and further forming a passage for the output switch unit to be communicated with the power supply input end and the power supply output end of the self-locking protection circuit.
6. The self-locking protection circuit according to claim 5, wherein in the output switch unit, the fourth set of voltage-dividing resistors comprises a seventh resistor and an eighth resistor connected in series;
one end of a seventh resistor is simultaneously connected with a power input end of the self-locking protection circuit and a source electrode of the second switching PMOS tube, the other end of the seventh resistor is connected with one end of an eighth resistor, and the other end of the eighth resistor is grounded, wherein a connection node of the seventh resistor and the eighth resistor is a voltage division node of the fourth group of voltage division resistors, the connection node is simultaneously connected with a drain electrode of the second switching PMOS tube and a grid electrode of the power supply switch PMOS tube, and two ends of the seventh resistor are respectively used as two input ends of the output switch unit;
and the emitter electrode of the NPN self-locking switch triode or the source electrode of the NMOS tube of the self-locking switch and the grounding end of the eighth resistor are connected with the common ground end of the self-locking protection unit and the output switch unit.
7. The self-locking protection circuit according to claim 6, wherein the overvoltage monitoring unit includes a first diode, a first operational amplifier, a ninth resistor and a tenth resistor, one end of the ninth resistor is connected to the drain of the PMOS transistor of the power switch, the other end of the ninth resistor is simultaneously connected to one end of the tenth resistor and the positive input terminal of the first operational amplifier, the other end of the tenth resistor is grounded, and the negative input terminal of the first operational amplifier is connected to a reference voltage; the output end of the first operational amplifier is connected with the anode of a first diode, the cathode of the first diode is connected with the feedback input end of the self-locking protection unit, the feedback input end is used for improving the conduction threshold of the NPN self-locking switch triode or the self-locking switch NMOS tube, and the output current of the over-current monitoring unit is prevented from flowing backwards by utilizing the unidirectional conductivity of the diode;
the connection node of the ninth resistor and the tenth resistor is used for acquiring a sampling voltage signal of a power supply output end of the self-locking protection circuit, and the sampling voltage signal is compared with a reference voltage by the first operational amplifier, so that the output end of the first operational amplifier outputs a voltage signal reflecting an overvoltage state.
8. The self-locking protection circuit according to claim 6, wherein the over-current monitoring unit includes a second diode, a second operational amplifier, a twelfth resistor, a thirteenth resistor and a fourteenth resistor, a positive input end of the second operational amplifier is a sampling end of the over-current monitoring unit, one end of the twelfth resistor is connected to a positive input end of the second operational amplifier, and the other end of the twelfth resistor is grounded and is used for sampling a current signal at a power supply output end of the self-locking protection circuit, wherein a sampling input end of the over-current monitoring unit is a positive input end of the second operational amplifier; the negative input end of the second operational amplifier is connected with one end of a fourteenth resistor, and the other end of the fourteenth resistor is grounded; one end of the thirteenth resistor is connected with the negative input end of the second operational amplifier, the other end of the thirteenth resistor is connected with the output end of the second operational amplifier, and the output end of the second operational amplifier is used for detecting whether the current signal sampled by the twelfth resistor is overcurrent or not; the output end of the second operational amplifier is connected with the anode of a second diode, the cathode of the second diode is connected with the feedback input end of the self-locking protection unit, the feedback input end of the self-locking protection unit is used for improving the conduction threshold of the NPN self-locking switch triode or the self-locking switch NMOS tube, and the output current of the overvoltage monitoring unit is prevented from flowing backwards by utilizing the unidirectional conductivity of the diode.
9. The self-locking protection circuit of claim 6, wherein the first switching PMOS transistor, the second switching PMOS transistor, and the power supply switch PMOS transistor are enhancement type PMOS transistors.
10. An adapter, characterized in that, the adapter includes the self-locking protection circuit of any claim 1 to 9, the power supply output terminal of the self-locking protection circuit and the sampling input terminal of the overcurrent monitoring unit inside the self-locking protection circuit are connected to the electrical equipment for supplying power to the electrical equipment, wherein, the power supply of the adapter is from the direct current power supply input by the signal input terminal of the self-locking protection circuit.
CN202010232674.XA 2020-03-28 2020-03-28 Over-current and over-voltage self-locking protection circuit and adapter Pending CN111327018A (en)

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Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113303799A (en) * 2021-05-21 2021-08-27 上海微创医疗机器人（集团）股份有限公司 Basin bottom detection equipment based on non-contact switch
CN114336517A (en) * 2021-12-30 2022-04-12 赛尔富电子有限公司 Overvoltage self-locking protection circuit and power supply
CN114583663A (en) * 2022-03-11 2022-06-03 苏州浪潮智能科技有限公司 Monitoring protection circuit and step-down switching power supply circuit
CN117458393A (en) * 2023-12-20 2024-01-26 天津航空机电有限公司 Protection circuit and protection method for electric equipment

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113303799A (en) * 2021-05-21 2021-08-27 上海微创医疗机器人（集团）股份有限公司 Basin bottom detection equipment based on non-contact switch
CN113303799B (en) * 2021-05-21 2023-09-22 上海微创医疗机器人（集团）股份有限公司 Basin bottom detection equipment based on non-contact switch
CN114336517A (en) * 2021-12-30 2022-04-12 赛尔富电子有限公司 Overvoltage self-locking protection circuit and power supply
CN114336517B (en) * 2021-12-30 2023-12-22 赛尔富电子有限公司 Overvoltage self-locking protection circuit and power supply
CN114583663A (en) * 2022-03-11 2022-06-03 苏州浪潮智能科技有限公司 Monitoring protection circuit and step-down switching power supply circuit
CN114583663B (en) * 2022-03-11 2023-07-21 苏州浪潮智能科技有限公司 Monitoring protection circuit and step-down type switch power supply circuit
CN117458393A (en) * 2023-12-20 2024-01-26 天津航空机电有限公司 Protection circuit and protection method for electric equipment

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