Short circuit protection circuit and electronic device

Abstract

The application discloses a short-circuit protection circuit and electronic equipment, the short-circuit protection circuit is connected between power supply and load, the short-circuit protection circuit includes sampling unit, delay unit, control unit and trigger unit;The sampling unit is used to collect short-circuit current, the delay unit is used to form delay voltage according to the short-circuit current, when the delay voltage is greater than the voltage threshold of the delay unit, the level signal of the delay voltage is sent to the control unit;The control unit is used to control the trigger unit to turn on or turn off the power supply of the load based on the level signal.Through the cooperation between the above-mentioned circuits, the false triggering of the circuit under the condition of capacitive load can be prevented, and the circuit can be disconnected in time when the short circuit of the circuit really occurs.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of circuit, in particular to a short circuit protection circuit and electronic equipment. BACKGROUND

[0002] In the field of power supply, when short circuit occurs at the output end of the power supply, the circuit can quickly respond to cut off the power supply loop to protect the circuit and the power supply from being damaged. If there is no short circuit protection function, the large current generated by the short circuit of the power supply will damage the device and even cause a fire. However, in the scenario with capacitive load, the circuit is often turned on at the moment, which causes a large loop current in the circuit, resulting in false triggering of the protection circuit. How to prevent the protection circuit from false triggering at the moment of circuit conduction in the capacitive load scenario and timely disconnect the circuit when the circuit is actually short-circuited is a problem to be solved. SUMMARY

[0003] In order to solve the above problems, the embodiment of the present application provides a short circuit protection circuit and electronic equipment, which can prevent false triggering of the circuit in the capacitive load scenario and timely disconnect the circuit when the circuit is actually short-circuited.

[0004] According to the first aspect of the embodiment of the present application, a short circuit protection circuit is provided, which is connected between a power supply and a load, and comprises a sampling unit, a delay unit, a control unit and a trigger unit.

[0005] The input end of the sampling unit is connected with the power supply, the output end of the sampling unit is connected with the input end of the trigger unit, the output end of the trigger unit is connected with the load, the collection end of the sampling unit is connected with the input end of the delay unit, the output end of the delay unit is connected with the input end of the control unit, and the output end of the control unit is connected with the control end of the trigger unit.

[0006] The sampling unit is used for collecting a short circuit current, the delay unit is used for forming a delay voltage according to the short circuit current, and when the delay voltage is greater than a voltage threshold of the delay unit, a level signal of the delay voltage is sent to the control unit; the control unit is used for controlling the trigger unit to be turned on or turned off to supply power to the load based on the level signal.

[0007] In an optional manner, the delay unit further comprises a delay capacitor, a first resistor and a voltage comparison chip.

[0008] The first end of the first resistor is connected with a sampling end of the sampling unit, the second end of the first resistor is connected with the first end of the delay capacitor, and the second end of the delay capacitor is grounded; the control end of the voltage comparison chip is connected with the first end of the delay capacitor, the input end of the voltage comparison chip is connected with the input end of the control unit, and the output end of the voltage comparison chip is grounded;

[0009] The voltage comparison chip is used for detecting the voltage of the delay capacitor through the control end of the voltage comparison chip, and when the voltage of the delay capacitor is detected to be greater than a voltage threshold, the voltage comparison chip is turned on to ground the input end of the control unit.

[0010] In an optional mode, the control unit comprises a first switch tube, a second switch tube, a third switch tube, a control chip and a chip power supply;

[0011] The control end of the first switch tube is connected with the input end of the voltage comparison chip, the input end of the first switch tube is connected with the chip power supply, the output end of the first switch tube is connected with the control end of the second switch tube, the input end of the second switch tube is connected with the first pin of the control chip, the control end of the third switch tube is connected with the second pin of the control chip, the input end of the third switch tube is connected with the control end of the trigger unit, and the output end of the second switch tube and the output end of the third switch tube are grounded;

[0012] The control chip is used for receiving the level signal through the first pin and controlling the turn-on or turn-off of the third switch tube through the second pin, and the third switch tube is used for controlling the turn-on or turn-off of the supply of the trigger unit to the load.

[0013] In an optional mode, the sampling unit comprises a sampling resistor, a second resistor, a third resistor and a fourth switch tube;

[0014] The first end of the sampling resistor is connected with the power supply, the second end of the sampling resistor is connected with the input end of the trigger unit, the second resistor and the third resistor are connected in series and then connected in parallel across the sampling resistor, the control end of the fourth switch tube is connected between the second resistor and the third resistor, the input end of the fourth switch tube is connected with the power supply, and the output end of the fourth switch tube is connected with the first end of the first resistor.

[0015] In an optional mode, the trigger unit comprises a fifth switch tube; the control end of the fifth switch tube is connected with the input end of the third switch tube, the input end of the fifth switch tube is connected with the second end of the sampling resistor, and the output end of the fifth switch tube is connected with the load.

[0016] In an alternative manner, the first resistor is connected in parallel with a digital potentiometer, a control end of the digital potentiometer is connected with the third pin of the control chip;

[0017] The third resistor is connected in parallel with a current sampling unit, the current sampling unit is connected with the fourth pin of the control chip, the current sampling unit is used to collect a first voltage value signal across the third resistor and send the first voltage value signal to the control chip, the control chip is used to calculate a current rising rate based on the first voltage value signal and adjust the resistance value of the digital potentiometer based on the current rising rate.

[0018] In an alternative manner, the short-circuit protection circuit further comprises a voltage sensor, the voltage sensor is connected between the power supply and the control chip;

[0019] The control chip is used to acquire a voltage value of the voltage sensor, and an alarm signal of internal short circuit of the power supply is sent out when the voltage value is lower than a preset value.

[0020] In an alternative manner, the control chip is further used to control the third switch tube to be closed and the fifth switch tube to be closed after maintaining the third switch tube to be opened for a first preset time length, so as to detect whether the load is still in a short circuit state.

[0021] In an alternative manner, the control chip is further used to control the fifth switch tube to be closed for a second preset time length when the load is still in a short circuit state, so as to detect whether the load continues to be in a short circuit state, wherein the second preset time length is greater than the first preset time length.

[0022] According to a second aspect of the embodiment of the present application, an electronic device is provided, the electronic device comprises a load, a battery and the short-circuit protection circuit according to any one of the implementation manners of the first aspect, and the short-circuit protection circuit is connected between the load and the battery.

[0023] The short circuit protection circuit provided by the application comprises a sampling unit, a delay unit, a control unit and a trigger unit, the sampling unit is used for collecting current in the circuit in real time, the delay capacitor in the delay unit can be rapidly charged when the circuit is short-circuited, so that the voltage of the delay capacitor is greater than the voltage threshold, a level signal is sent to the control unit, and the control unit controls the trigger unit to disconnect the link between the power supply and the load based on the level signal. In the case that the circuit is connected to a capacitive load, the capacitive load is equivalent to a short circuit in a very short time when the circuit is turned on, and a transient short-circuit current is generated in the circuit. Since the transient short-circuit current exists for a very short time, the delay capacitor can be reasonably set to charge only in a very short time, so that the voltage of the delay capacitor is less than the voltage threshold, and the subsequent control unit and the trigger unit are not triggered, thereby preventing the circuit from being triggered by mistake in the case of the capacitive load. BRIEF DESCRIPTION OF DRAWINGS

[0024] The accompanying drawings are included to provide a further understanding of the application, and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments of the application and, together with the description, serve to explain the principles of the application. In the drawings:

[0025] Figure 1 is a connection diagram of a short circuit protection circuit, a load and a power supply provided by an embodiment of the application;

[0026] Figure 2 is a schematic diagram of a short circuit protection circuit provided by an embodiment of the application;

[0027] Figure 3 is an internal equivalent circuit diagram of a voltage comparison chip provided by an embodiment of the application. DETAILED DESCRIPTION

[0028] In order for those skilled in the art to better understand the technical solutions of the application, the application will be described in detail below with reference to the drawings and specific embodiments. Although the drawings and specific embodiments describe exemplary embodiments of the application, it should be understood that the application can be implemented in various forms and should not be limited by the embodiments described herein.

[0029] The terms "first", "second", and the like used in the application do not represent any order, quantity or importance, but are only used to distinguish. The terms "comprise", "comprising", "include", "including" and the like used in the application mean that the elements before the terms encompass the elements listed after the terms, and do not exclude the possibility of also encompassing other elements. The technical solutions of the application are not limited to the execution order described in the embodiments, and each step in the execution order can be combined, decomposed or exchanged in order, as long as the logical relationship of the execution content is not affected.

[0030] All the terms used in the present application, including technical terms or scientific terms, have the same meaning as understood by those of ordinary skill in the art to which the present application pertains, unless otherwise specifically defined. It should also be understood that terms defined in general dictionaries should be interpreted in a manner consistent with their meanings in the context of the relevant art, and should not be interpreted in an idealized or excessively formalized sense, unless specifically defined herein. Techniques and equipment known to those of ordinary skill in the relevant art can not be discussed in detail, but in appropriate cases, the techniques and equipment should be considered part of the specification.

[0031] In the field of power supply, when a short circuit occurs at the output end of the power supply, the circuit can quickly respond to cut off the power supply circuit to protect the circuit and the power supply from damage. If there is no short circuit protection function, the large current generated by the short circuit of the power supply will damage the device and even cause a fire. However, in the case of a capacitive load, the circuit is often turned on at the moment, which causes a large loop current in the circuit, resulting in false triggering of the protection circuit. How to prevent the protection circuit from false triggering at the moment of circuit conduction in the capacitive load scenario and timely disconnect the circuit when a real short circuit occurs in the circuit is often a design difficulty.

[0032] The short circuit protection circuit provided by the embodiments of the present application can prevent the protection circuit from false triggering at the moment of circuit conduction in the capacitive load scenario, while timely disconnecting the circuit to protect the protection circuit when a real short circuit occurs in the circuit. The short circuit protection circuit is connected between a power supply and a load, and includes a sampling unit, a delay unit, a control unit and a triggering unit. An input end of the sampling unit is connected with the power supply, an output end of the sampling unit is connected with an input end of the triggering unit, an output end of the triggering unit is connected with the load, a collection end of the sampling unit is connected with an input end of the delay unit, an output end of the delay unit is connected with an input end of the control unit, and an output end of the control unit is connected with a control end of the triggering unit. The sampling unit is configured to collect a short circuit current, the delay unit is configured to form a delay voltage according to the short circuit current, and send a level signal of the delay voltage to the control unit when the delay voltage is greater than a voltage threshold of the delay unit. The control unit is configured to control the triggering unit to turn on or turn off the power supply to the load based on the level signal.

[0033] To solve the above problems, as shown in Figure 1 Figure 1 is a connection diagram of a short circuit protection circuit provided by the embodiments of the present application and a load and a power supply.

[0034] ​Specifically, the short-circuit protection circuit provided by the application comprises a sampling unit, a delay unit, a control unit and a triggering unit. The sampling unit is used to collect current in the circuit in real time. When a short circuit occurs in the circuit, the short-circuit current can rapidly charge the delay unit to form a delay voltage. When the delay voltage is greater than a voltage threshold value in the delay unit, a level signal is sent to the control unit. The control unit controls the triggering unit to cut off power supply to the load based on the level signal. In the case of connecting a capacitive load to the circuit, the capacitive load is equivalent to a short circuit in a very short time when the circuit is turned on. A transient short-circuit current is generated in the circuit. Since the transient short-circuit current exists for a very short time, the delay unit is only charged for a very short time by setting the delay of the internal circuit of the delay unit, so that the delay voltage formed is less than the voltage threshold value in the delay unit, and the subsequent control unit and the triggering unit are not triggered, thereby preventing the circuit from being mistakenly triggered in the case of the capacitive load.

[0035] In some embodiments, the power supply can be a battery or a battery pack, which is a device that converts chemical energy into electrical energy through a chemical reaction, can be composed of one or more electrochemical units (battery cells), each unit containing positive and negative electrodes, electrolyte and separator material, and can continuously provide current in a closed circuit. Its core function is to store and release electrical energy.

[0036] The power supply in the embodiment can be a lead-acid battery, a lithium-ion battery, a nickel-cadmium battery, an alkaline battery, etc. for providing stable direct current.

[0037] Specifically, the voltage threshold value in the delay unit can be set to different voltage threshold values for different load capacitance values, so that the short-circuit protection circuit of the application can be applied to different specific scenarios.

[0038] In some embodiments, as shown in Figure 2 and Figure 3 , the short-circuit protection circuit provided by the application comprises a sampling unit, a delay unit, a control unit and a triggering unit. The sampling unit is used to collect current in the circuit in real time. When a short circuit occurs in the circuit, the short-circuit current can rapidly charge the delay unit to form a delay voltage. When the delay voltage is greater than a voltage threshold value in the delay unit, a level signal is sent to the control unit. The control unit controls the triggering unit to cut off power supply to the load based on the level signal. In the case of connecting a capacitive load to the circuit, the capacitive load is equivalent to a short circuit in a very short time when the circuit is turned on. A transient short-circuit current is generated in the circuit. Since the transient short-circuit current exists for a very short time, the delay unit is only charged for a very short time by setting the delay of the internal circuit of the delay unit, so that the delay voltage formed is less than the voltage threshold value in the delay unit, and the subsequent control unit and the triggering unit are not triggered, thereby preventing the circuit from being mistakenly triggered in the case of the capacitive load. Figure 2 is a short-circuit protection circuit schematic diagram provided by the embodiment of the application, Figure 3 is an internal equivalent circuit diagram of a voltage comparison chip. The delay unit further comprises a delay capacitor C99, a first resistor R225 and a voltage comparison chip U13.

[0039] The first end of the first resistor R225 is connected with the sampling end of the sampling unit, the second end of the first resistor R225 is connected with the first end of the delay capacitor C99, and the second end of the delay capacitor C99 is grounded; the control end of the voltage comparison chip U13 is connected with the first end of the delay capacitor C99, the input end of the voltage comparison chip U13 is connected with the input end of the control unit, and the output end of the voltage comparison chip U13 is grounded; the voltage comparison chip is used for detecting the voltage of the delay capacitor through the control end of the voltage comparison chip, and when it is detected that the voltage of the delay capacitor is greater than a voltage threshold, the voltage comparison chip is turned on to ground the input end of the control unit.

[0040] Specifically, the voltage comparison chip U13 can be a three-terminal adjustable shunt reference source chip, a precise adjustable shunt reference source chip, etc., such as TL431, TL432, LM431, etc. The specific function of the voltage comparison chip can be shown in the function module diagram (CATHODE is the input end of the voltage comparison chip U13, ANODE is the output end of the voltage comparison chip U13, and D1 is a reverse diode). Figure 3 From the diagram, it can be seen that V ref is an internal 2.5V reference source connected to the reverse input end of the operational amplifier U1. According to the characteristics of the operational amplifier U1, only when the voltage of the REF end (i.e. the control end of the voltage comparison chip U13) is higher than V ref (2.5V), current will flow through the transistor Q1. When the same-phase input voltage is less than 2.5V, the transistor Q1 is in the off state (in the ideal state), and with the slight change of the voltage of the REF end, the current through the transistor will change from 1mA to 100mA.

[0041] From the above characteristics of the voltage comparison chip U13, it can be understood that the voltage comparison chip U13 is a controllable electronic switch. When the voltage value of the delay capacitor C99 is equal to or greater than 2.5V, the upper and lower pins of the voltage comparison chip U13 are turned on, and when the voltage value of the delay capacitor C99 is less than 2.5V, the upper and lower pins of the voltage comparison chip U13 are not turned on. Therefore, the voltage comparison chip U13 determines whether to turn on by comparing whether the voltage value of the control end of the voltage comparison chip U13 to ground is greater than 2.5V.

[0042] Specifically, the first resistor R225 can be 10K to 20K, and the delay capacitor C99 can be 1uF to 10uF. According to the time constant formula: τ=RC, for example, the first resistor R225 is 10K, and the delay capacitor C99 is 4.7uF, then τ=RC=10K*4.7uF=47ms. According to the actual capacitive load, the time constant can be adjusted by adjusting the size of the first resistor R225 and the delay capacitor C99, and the time for the delay capacitor C99 to charge from 0V to 2.5V is indirectly adjusted.

[0043] In some embodiments, the control end of the voltage comparison chip U13 can be connected in parallel with the first pull-down resistor R222 and the first filter capacitor C100. The first pull-down resistor R222 is used to provide a stable static working point voltage to the control end of the voltage comparison chip U13, preventing the control end of the voltage comparison chip U13 from being damaged by excessively high voltage. The first filter capacitor C100 is used to provide AC bypass, with low impedance to high-frequency noise, short-circuiting high-frequency noise to ground to prevent false triggering caused by high-frequency noise interference. At the same time, in the case where the delay unit is not working, the first pull-down resistor R222 can also provide a discharge channel for the delay capacitor C99, discharging the electrical energy in the delay capacitor C99 in time to reset the delay unit and provide realizability for the next delay unit operation.

[0044] The present embodiment realizes the delay conduction of the circuit through hardware circuit design, thereby controlling the short-circuit protection action of the subsequent circuit. The first resistor R225 and the delay capacitor C99 in the delay unit form a charging circuit, and the voltage comparison chip U13 accurately judges whether the voltage of the delay capacitor C99 reaches the preset voltage, ensuring that the protection is triggered only in the actual short-circuit state of the circuit, thereby improving the anti-interference ability of the circuit.

[0045] In some embodiments, the control unit includes a first switch tube Q26, a second switch tube Q27, a third switch tube Q12, a control chip (not shown in the figure), and a chip power supply +5VSB. The control end of the first switch tube Q26 is connected with the input end of the voltage comparison chip U13, the input end of the first switch tube Q26 is connected with the chip power supply +5VSB, the output end of the first switch tube Q26 is connected with the control end of the second switch tube Q27, the input end of the second switch tube Q27 is connected with the first pin OSP of the control chip, the control end of the third switch tube Q12 is connected with the second pin SWCLK of the control chip, the input end of the third switch tube Q12 is connected with the control end of the trigger unit, and the output end of the second switch tube Q27 and the output end of the third switch tube Q12 are grounded.

[0046] The control chip is configured to receive the level signal through the first pin, control the third switch tube to be turned on or turned off through the second pin, and the third switch tube is configured to control the trigger unit to supply power to the load or to disconnect the supply of power to the load.

[0047] In this embodiment, as shown in the figure, Figure 2 The first switch tube Q26 can be a PNP type triode, and the second switch tube Q27 and the third switch tube Q12 can be NPN type triodes. When the voltage comparison chip U13 is turned on, the control end potential of the first switch tube Q26 is pulled low, so that the first switch tube Q26 is turned on. When the first switch tube Q26 is turned on, the link between the chip power supply +5VSB and the control end of the second switch tube Q27 is turned on, so that the potential of the control end of the second switch tube Q27 is pulled high, triggering the second switch tube Q27 to be turned on, and the first pin OSP potential of the control chip is pulled low. After the control chip detects the low level signal of the first pin OSP, the second pin SWCLK outputs a low level signal, so that the third switch tube Q12 is turned off. At this time, the control unit sends a disconnect main circuit signal to the trigger unit.

[0048] The control unit in this embodiment realizes multi-stage control through multiple triodes. Compared with single-stage control, when a short-term interference signal is received, only one triode is turned on. Since the triode is turned on for a short time, the next triode cannot be turned on, thereby avoiding mis-triggering caused by interference signals. For example, electromagnetic interference of a walkie-talkie, high-frequency interference of a signal transmitting station, etc. This “cascade connection” is essentially a double filtering of “time + amplitude”. A short-term interference (such as a pulse of ns level) cannot cross the cumulative threshold of multiple triode turn-on times, and if the interference amplitude is insufficient, a triode at a certain stage cannot be turned on, and the signal chain is interrupted. Through the above setting, the anti-interference performance and stability of the overall circuit are improved.

[0049] In some embodiments, the above-mentioned switch tubes can also be mos tubes or replaced by other types of triodes, which are not specifically limited in this application. After replacing the switch tubes with different types, adaptive adjustments are made in the circuit design, which is a routine design for those skilled in the art, and will not be specifically listed and described herein.

[0050] It should be noted that, Figure 2 The resistors R224, R227, R52 and R112 in the figure are current-limiting resistors, which play a current-limiting role; the resistors R223, R228 and R113 are pull-up resistors or pull-down resistors, which provide a certain level for the switch tube to prevent the switch tube from being mistakenly turned on; and the capacitors C101, C102 and C35 are filter capacitors, which play a role in stabilizing the control voltage and suppressing high-frequency interference.

[0051] In some embodiments, the sampling unit comprises a sampling resistor R53, a second resistor R220, a third resistor R221, and a fourth switch Q25.

[0052] The first end of the sampling resistor R53 is connected to the power supply, the second end of the sampling resistor R53 is connected to the input end of the trigger unit, the second resistor R220 and the third resistor R221 are connected in series and then connected in parallel across the sampling resistor R53, the control end of the fourth switch Q25 is connected between the second resistor R220 and the third resistor R221, the input end of the fourth switch Q25 is connected to the power supply, and the output end of the fourth switch Q25 is connected to the first end of the first resistor R225.

[0053] Specifically, the design of the sampling resistor R53 needs to meet the rated power and resistance value design to avoid large loss of the sampling resistor during normal operation of the circuit, thereby affecting the working efficiency of the circuit. For example, the resistance value of the sampling resistor R53 can be 10 mΩ to 40 mΩ. For example, when the sampling resistor R53 is 40 mΩ and the rated working current of the circuit is 5 A, the power of the sampling resistor R53 at this time is I2*R=1 W, and the sampling resistor R53 needs to be selected with a rated power greater than 1 W.

[0054] In some embodiments, as shown in Figure 2 The fourth switch Q25 can be a PNP triode, and the control end and the input end of the fourth switch Q25 can be connected in parallel with the third resistor R221. When a short circuit occurs in the circuit, the voltage across the sampling resistor R53 will suddenly rise due to the direct connection of the sampling resistor R53 to the main circuit, and the voltage across the second resistor R220 and the third resistor R221 will also rise accordingly. When the voltage across the third resistor R221 is higher than the turn-on voltage of the fourth switch Q25, the fourth switch Q25 is turned on. The sampling unit flows the short-circuit current signal into the delay unit through the fourth switch Q25.

[0055] Through the above arrangement of the sampling unit, the sampling unit can obtain the short-circuit current signal of the main circuit in time, realize sensitive detection of the short-circuit current, and adjust the sampling sensitivity by reasonably selecting the value of the sampling resistor R53. The performance and safety of the short-circuit protection circuit are improved while the cost is reduced.

[0056] Further, the control unit in the present embodiment does not have an operational amplifier working component, which can avoid the need to provide an additional power supply for the operational amplifier. The control unit in the present embodiment directly uses the chip power supply +5VSB, which greatly simplifies the circuit design, and realizes circuit control through multiple triodes, which can be directly applied to high-voltage scenarios (such as 72V battery-powered working scenarios).

[0057] It should be noted that the capacitor C98 in the sampling unit is a filter capacitor, which plays a role in stabilizing the control voltage and suppressing high-frequency interference.

[0058] In some embodiments, the trigger unit comprises a fifth switch tube Q8, the control end of the fifth switch tube Q8 is connected with the input end of the third switch tube Q12, the input end of the fifth switch tube Q8 is connected with the second end of the sampling resistor R53, and the output end of the fifth switch tube Q8 is connected with the load.

[0059] In some embodiments, the fifth switch tube Q8 can be a P-channel depletion MOS tube. For example, when the fourth switch tube Q25 is disconnected, the voltage difference between the input end and the control end of the fifth switch tube Q8 is 0, that is, the control end of the fifth switch tube Q8 receives a short-circuit disconnect signal, triggering the fifth switch tube Q8 to be disconnected, thereby realizing the disconnection of the link between the power supply and the load.

[0060] In some embodiments, as shown in Figure 2 In some environments requiring large current operation, the trigger unit can further comprise a sixth switch tube Q24 connected in parallel with the fifth switch tube Q8, for sharing the large operating current in the main circuit and preventing damage caused by overloading of a single switch tube.

[0061] In some embodiments, as shown in Figure 2 The fifth switch tube Q8 and the sampling resistor R53 can be provided with one or more parallel diodes (such as D42 in Figure 2 for preventing the inductive current in the inductive load from impacting the power supply and causing damage to the power supply or the circuit.

[0062] Through the above setting of the trigger unit, when the circuit is short-circuited, the trigger unit can timely and effectively disconnect the link between the power supply and the load, thereby avoiding unpredictable serious consequences caused by circuit short-circuit.

[0063] In other embodiments, the fifth switch tube Q8 and the sixth switch tube Q24 can be other types of MOS tubes, which are not specifically limited in the present application.

[0064] It should be noted that the resistors R184, R185 and R186 in the trigger unit are pull-up resistors or pull-down resistors, which provide a certain level for the switch tube to prevent the switch tube from being mistakenly turned on; the capacitor C58 is a filter capacitor, which plays a role in stabilizing the control voltage and suppressing high-frequency interference.

[0065] In some embodiments, the first resistor R225 is connected with a digital potentiometer in parallel, and the control end of the digital potentiometer is connected with the third pin of the control chip.

[0066] The third resistor is connected in parallel with a current sampling unit, the current sampling unit is connected with a fourth pin of the control chip, the current sampling unit is used for collecting a first voltage value signal across the third resistor and sending the first voltage value signal to the control chip, and the control chip is used for calculating a current rising rate based on the first voltage value signal and adjusting a resistance value of the digital potentiometer based on the current rising rate.

[0067] In the embodiment, the digital potentiometer can be a digital potentiometer such as MCP41010, which can control the resistance value through the I / O port of the control chip. The control chip calculates the current rising rate through the current sampling unit, which can be used to calculate the capacitive reactance value of the load, and adaptively adjusts the resistance value of the digital potentiometer according to the calculated capacitive reactance value, so that the delay unit intelligently adapts to different loads (automatically identifies capacitive load, inductive load or pure resistive load), and adjusts the delay time according to different loads.

[0068] Through the intelligent design of the adaptive delay protection circuit, the reliability and compatibility of the power supply system are significantly improved, and the application scenario which needs to adapt to various load characteristics is particularly suitable.

[0069] In some embodiments, the short-circuit protection circuit further comprises a voltage sensor connected between the power supply and the control chip; and the control chip is configured to acquire a voltage value of the voltage sensor, and send an alarm signal of internal short circuit of the power supply when the voltage value is lower than a preset value.

[0070] The power supply protection method provided in the embodiment can improve the system safety performance of the short-circuit protection circuit. In actual industrial application scenarios, the working environment of the power supply is relatively complex, and internal short circuit of the power supply is inevitable. The voltage sensor is used to detect the voltage of the power supply in real time. When internal short circuit of the power supply occurs, the voltage value of the voltage sensor acquired by the control chip will change greatly. The control chip sends an alarm in a timely manner according to a preset program, so as to avoid the expansion of loss and further improve the system safety performance of the short-circuit protection circuit.

[0071] In some embodiments, the control chip is further configured to control the third switch tube to be closed and the fifth switch tube to be closed after maintaining the third switch tube to be disconnected for a first preset time length, so as to detect whether the load is still in a short-circuit state.

[0072] Specifically, the internal program of the control chip adopts a preset time interval to test intermittently. For example, in the case that the fifth switch tube Q8 is controlled to be disconnected when the circuit is short-circuited, the fifth switch tube Q8 is closed again every 3 seconds. If the circuit is still in a short-circuit state, the fifth switch tube Q8 is continued to be disconnected, and the above cycle is repeated until the short-circuit fault is removed.

[0073] In some embodiments, the control chip internal program can also perform a soft start delay operation. After short-circuit protection, the system is reset after a delay of T seconds (such as 100 ms), avoiding the second damage caused by the immediate restart after a transient short circuit. Further, the control chip internal program also has a multiple protection locking function. If the short-circuit protection is triggered continuously for N times (for example, 3 times continuously within 10 s) in a short time, the system is locked and an alarm is given through the LED / serial port, and manual reset is required.

[0074] By means of the control chip, the intelligent degree of the circuit is improved, the power consumption of the circuit is significantly reduced, the service life of the devices in the circuit is prolonged, and the reliability and economy of the circuit are greatly improved.

[0075] In some embodiments, the control chip is further configured to control the fifth switch tube to be closed within a second preset time period when the load is still in a short-circuit state, to detect whether the load continues to be in a short-circuit state, wherein the second preset time period is greater than the first preset time period.

[0076] In some embodiments, the control chip internal program can also use another similar rest test mode. For example, the fifth switch tube Q8 is closed again every 5 seconds, and if the circuit is still in a short-circuit state, the fifth switch tube Q8 is continuously opened, and the above cycle is repeated. Until 5 minutes later, the program executes the operation of closing the fifth switch tube Q8 again every 1 minute, and if the circuit is still in a short-circuit state, the fifth switch tube Q8 is continuously opened, and the above cycle is repeated. Until 30 minutes later, if the circuit is still in a short-circuit state, the fifth switch tube Q8 is opened, and the rest test is no longer performed until the circuit is reset by manual intervention to solve the short-circuit fault of the circuit.

[0077] Through the above setting, the continuous closing and opening of the switch tube can be avoided, and the service life of the switch tube is prolonged.

[0078] The embodiments of the present application also provide an electronic device, which comprises a load, a battery, and a short-circuit protection circuit according to any one of the above embodiments and modes, wherein the short-circuit protection circuit is connected between the load and the battery.

[0079] The short circuit protection circuit of the electronic device can include a sampling unit, a delay unit, a control unit and a triggering unit, the sampling unit collects current in the circuit in real time, in the case of actual short circuit of the circuit, the delay capacitor C99 can be rapidly charged, so that the voltage of the delay capacitor C99 is greater than the voltage threshold, a level signal is sent to the control unit, the control unit controls the triggering unit to disconnect the link between the power supply and the load based on the level signal. In the case of connecting a capacitive load to the circuit, the capacitive load is equivalent to a short circuit in a very short time when the circuit is turned on, a transient short circuit current will be generated in the circuit. Since the transient short circuit current exists for a very short time, by reasonably setting the delay capacitor C99, the delay capacitor C99 can be charged only in a very short time, so that the voltage of the delay capacitor C99 is less than the voltage threshold, and the subsequent control unit and the triggering unit will not be triggered, preventing the circuit from being triggered by mistake in the case of capacitive load.

[0080] The electronic device in the embodiment can be, for example, a portable electronic device, a medical electronic device, an emergency electronic device, an energy storage network device, a sensor network device, or the like.

[0081] In the specification provided herein, a large number of specific details are described. However, it can be understood that the embodiments of the present application can be practiced without these specific details. Similarly, in order to simplify the present application and help understand one or more of the various inventive aspects, in the above description of the exemplary embodiments of the present application, various features of the embodiments of the present application are sometimes grouped together into a single embodiment, figure, or description thereof. Among them, the claims following the detailed description are thus expressly incorporated into the detailed description, wherein each claim itself is a separate embodiment of the present application.

[0082] Those skilled in the art can understand that the modules in the device in the embodiments can be adaptively changed and arranged in one or more devices different from the embodiments. The modules or units or components in the embodiments can be combined into one module or unit or component, and in addition, they can be divided into multiple sub-modules or sub-units or sub-components. Except that at least some of such features and / or processes or units are mutually exclusive.

[0083] It should be noted that the above-mentioned embodiments illustrate rather than limit the application, and that those skilled in the art will be able to design many alternative embodiments without departing from the scope of the appended claims. In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. The word 'comprising' does not exclude the presence of elements or steps other than those listed in a claim. The word 'a' or 'an' preceding an element does not exclude the presence of a plurality of such elements. The application can be implemented by means of hardware comprising several distinct elements, and by means of a suitably programmed computer. In the unit claim enlisting a number of means, several of these means can be embodied by one and the same item of hardware.

Claims

1. A short-circuit protection circuit, characterized by comprising: The short-circuit protection circuit is connected between the power supply and the load, and comprises a sampling unit, a delay unit, a control unit and a triggering unit; The input end of the sampling unit is connected with the power supply, the output end of the sampling unit is connected with the input end of the triggering unit, the output end of the triggering unit is connected with the load, the collection end of the sampling unit is connected with the input end of the delay unit, the output end of the delay unit is connected with the input end of the control unit, and the output end of the control unit is connected with the control end of the triggering unit; The sampling unit is used for collecting a short-circuit current, the delay unit is used for forming a delay voltage according to the short-circuit current, and when the delay voltage is greater than a voltage threshold of the delay unit, a level signal of the delay voltage is sent to the control unit; and the control unit is used for controlling the triggering unit to turn on or turn off the power supply to the load based on the level signal. The delay unit comprises a delay capacitor, a first resistor and a voltage comparison chip. The first end of the first resistor is connected with the sampling end of the sampling unit, the second end of the first resistor is connected with the first end of the delay capacitor, and the second end of the delay capacitor is grounded; the control end of the voltage comparison chip is connected with the first end of the delay capacitor, the input end of the voltage comparison chip is connected with the input end of the control unit, and the output end of the voltage comparison chip is grounded. The voltage comparison chip is used for detecting the voltage of the delay capacitor through the control end of the voltage comparison chip, and when it is detected that the voltage of the delay capacitor is greater than a voltage threshold, the voltage comparison chip is turned on to ground the input end of the control unit.

2. The short circuit protection circuit according to claim 1, characterized in that The control unit comprises a first switch tube, a second switch tube, a third switch tube, a control chip and a chip power supply; The control end of the first switch tube is connected with the input end of the voltage comparison chip, the input end of the first switch tube is connected with the chip power supply, the output end of the first switch tube is connected with the control end of the second switch tube, the input end of the second switch tube is connected with the first pin of the control chip, the control end of the third switch tube is connected with the second pin of the control chip, the input end of the third switch tube is connected with the control end of the triggering unit, and the output end of the second switch tube and the output end of the third switch tube are grounded; The control chip is used for receiving the level signal through the first pin and controlling the third switch tube to turn on or turn off through the second pin, so as to turn on or turn off the power supply to the load by the triggering unit.

3. The short circuit protection circuit of claim 2, wherein The sampling unit comprises a sampling resistor, a second resistor, a third resistor and a fourth switch tube; The first end of the sampling resistor is connected with the power supply, the second end of the sampling resistor is connected with the input end of the trigger unit, the second resistor and the third resistor are connected in series and then connected in parallel across the sampling resistor, the control end of the fourth switch tube is connected between the second resistor and the third resistor, the input end of the fourth switch tube is connected with the power supply, and the output end of the fourth switch tube is connected with the first end of the first resistor.

4. The short circuit protection circuit of claim 3, wherein The trigger unit comprises a fifth switch tube, the control end of the fifth switch tube is connected with the input end of the third switch tube, the input end of the fifth switch tube is connected with the second end of the sampling resistor, and the output end of the fifth switch tube is connected with the load.

5. The short circuit protection circuit of claim 4, wherein A digital potentiometer is connected in parallel across the first resistor, the control end of the digital potentiometer is connected with the third pin of the control chip, The third resistor is connected in parallel with a current sampling unit, the current sampling unit is connected with the fourth pin of the control chip, the current sampling unit is used for collecting a first voltage value signal across the third resistor and sending the first voltage value signal to the control chip, the control chip is used for calculating a current rising rate based on the first voltage value signal and adjusting the resistance value of the digital potentiometer based on the current rising rate.

6. The short circuit protection circuit of claim 5, wherein The short-circuit protection circuit further comprises a voltage sensor connected between the power supply and the control chip. The control chip is used for acquiring a voltage value of the voltage sensor, and an alarm signal of internal short circuit of the power supply is sent when the voltage value is lower than a preset value.

7. The short circuit protection circuit of claim 6, wherein The control chip is further used for controlling the third switch tube and the fifth switch tube to be closed after maintaining the third switch tube to be disconnected for a first preset time length, so as to detect whether the load is still in a short circuit state.

8. The short circuit protection circuit of claim 7, wherein The control chip is further used for controlling the fifth switch tube to be closed for a second preset time length when the load is still in a short circuit state, so as to detect whether the load continues to be in a short circuit state, wherein the second preset time length is greater than the first preset time length.

9. An electronic device, comprising: The electronic device comprises a load, a battery and the short-circuit protection circuit according to any one of claims 1-8, and the short-circuit protection circuit is connected between the load and the battery.

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