A power distribution circuit with short-circuit protection function

Abstract

The present invention provides a power distribution circuit with short-circuit protection function, which includes a power switch circuit, a signal amplifying circuit, a logic judgment circuit, a soft-start driving circuit and a start-up sealing circuit; the signal output end of the power switch circuit is connected to the input end of the signal amplifying circuit, the output end of the signal amplifying circuit is connected to one input end of the soft-start driving circuit through the logic judgment circuit, the output end of the start-up sealing circuit is connected to the other input end of the soft-start driving circuit, and the output end of the soft-start driving circuit is connected to the signal input end of the power switch circuit. The technical solution of the present invention has a simple circuit structure, has short-circuit protection and on-off control functions, has a surge current suppression function at the moment of connection, the circuit can be restarted after protection occurs, and can supply power normally after the fault is eliminated; the power switch has a low voltage drop and low power consumption at the moment of load short circuit, the circuit response time is short, the short-circuit current peak is controllable, and there is no influence on the operation of other power loads during the short circuit.

Description

Technical Field

[0001] The invention belongs to the field of satellite power supply and distribution, and in particular relates to a power distribution circuit with a short-circuit protection function. Background Art

[0002] Satellite power supply and distribution generally adopts the method of centralized power supply and decentralized power distribution. A power supply device, namely the power controller, generates the stable power supply bus required by the satellite, which is distributed to each power load through the distributor and cables. The distributor is equipped with independent fuses and relay switches on each distribution branch. In order to prevent the relay contacts from burning or the fuse from being damaged by the instantaneous surge current when the relay is turned on, a special surge suppression circuit needs to be designed. When a power load or cable on a certain line is short-circuited, the short-circuit current rises rapidly, and the high current energy flowing through the fuse blows the fuse, disconnecting the faulty branch from the power supply bus, thereby protecting the power supply bus of the entire satellite.

[0003] At present, technologies such as satellite-borne synthetic aperture radar, laser, and electric propulsion are developing rapidly. The power required by their electrical loads can reach 5KW to 20KW, the power voltage is generally 100V bus, and the required current can reach tens to hundreds of amperes. On the one hand, there are no suitable high-voltage and high-current relays available for aerospace applications. On the other hand, the maximum current value of the currently available aerospace-grade fuses is only 15A, and the typical fusing time is at the ms level. The fusing energy required varies greatly from batch to batch, and it is often necessary to use multiple fuses in parallel when used in high-current situations. However, satellites generally require a maximum parallel number of 4 fuses, so the maximum output power is only about 3KW, which is difficult to use in higher power situations. Moreover, parallel connection will further increase the fusing energy. The measured rising slope of the fusing current at the instant of fusing is greater than 10 6 A / S, the following problems may also occur during the circuit breaker period:

[0004] (1) The amplitude of the fusing current is uncontrollable due to the influence of the internal resistance of the line. The maximum peak value can reach hundreds of amperes or even thousands of amperes, causing the breakdown and failure of semiconductor devices in the power supply link, resulting in secondary faults, which seriously affects the power supply and distribution safety of the entire satellite.

[0005] (2) The power bus voltage drops by tens of volts, which may cause other electrical equipment to reset due to undervoltage at best, or trigger the internal overcurrent protection of the power supply equipment at worst, causing the entire satellite to lose power, resulting in irreparable losses.

[0006] The fuse is a non-self-recovering device. After it blows, the power supply link of the power load is disconnected. Even if the short-circuit fault of the power load is eliminated, it cannot be powered normally. Since the fuse cannot be replaced while the satellite is in orbit, the power load will be permanently lost, affecting the operation of the entire satellite.

[0007] The European Space Agency (ESA) has proposed the use of solid-state current limiting protectors to replace fuses and relay switches, and has been widely used on low-voltage 28V and 42V buses. Its working principle is to force the solid-state switch to work in the linear resistance zone to limit the short-circuit current for a period of time after the short circuit. At this time, the bus voltage drops completely at both ends of the solid-state switch. During the current limiting period, the actual power consumption of the solid-state switch is equal to the bus voltage multiplied by the current limiting protection value. In low-voltage and low-power situations, this value (generally a few hundred watts) is less than the rated power consumption of the solid-state switch, so it can play a better protective role. However, in high-voltage and high-power situations, the solid-state power of the current limiting device will reach several watts or even tens of thousands of watts, which exceeds the maximum power consumption that the solid-state device can withstand, causing the solid-state device to burn out. Therefore, this technology is difficult to apply in high-voltage and high-power situations.

[0008] In industrial applications, products are all maintainable, so short-circuit protection fault isolation is generally achieved by connecting a fuse in series with the power input. Currently, some DCDC switching power converter products are also designed with short-circuit protection functions, such as Figure 1 As shown, its power switch tube and sampling resistor are generally connected in series between the transformer and the power supply loop. When there is no short circuit fault, the power switch is in a frequent switching state under the control of pulse width modulation PWM to generate an AC square wave for the transformer or magnetic devices such as inductors to transfer energy. When a short circuit fault occurs at the output end of the power supply, PWM becomes a normally low state and the power switch is disconnected. Since its sampling resistor is set at the power supply loop, it cannot play a protective role when a short circuit fault occurs in the front-end circuit, such as the EMC filter circuit, the transformer circuit, etc. In addition, unlike the normal working state of the power switch in the distribution circuit, its power switch is always in an alternating on-off state. For the above two reasons, this protection circuit cannot be used in the distribution circuit. Summary of the invention

[0009] In view of the above technical problems, the present invention discloses a distribution circuit with short-circuit protection function, which solves the following technical problems: the solid-state current limiting protection technology in satellite high-power power supply and distribution is difficult to apply in high-voltage and high-power distribution occasions due to the power consumption limitation of the device, the short-circuit protection circuit of the switching power supply converter cannot be applied in the distribution circuit, the aerospace-grade high-current fuse and relay device selection is difficult and the fusing current is large, the power supply bus has a large drop, which affects the safety of satellite power supply, and it is difficult to restore power supply after the fault is eliminated.

[0010] To this end, the technical solution adopted by the present invention is:

[0011] A power distribution circuit with a short-circuit protection function comprises a power switch circuit, a signal amplifying circuit, a logic judgment circuit, a soft-start drive circuit and a start-up sealing circuit; the power input end of the power switch circuit is connected to a power supply device, and the power output end of the power switch circuit is connected to a power load; the signal output end of the power switch circuit is connected to the input end of the signal amplifying circuit, the output end of the signal amplifying circuit is connected to an input end of a soft-start drive circuit through a logic judgment circuit, the output end of the start-up sealing circuit is connected to the other input end of the soft-start drive circuit, and the output end of the soft-start drive circuit is connected to the signal input end of the power switch circuit.

[0012] The technical solution of the present invention can be applied to the power distribution circuit of satellite high-power loads, connected in series between satellite power supply equipment and power loads, and has functions such as on-off control, current surge suppression, and short-circuit protection.

[0013] As a further improvement of the present invention, the power switch circuit includes a sampling resistor R11, a MOS tube Q11 and a diode D11; the drain of the MOS tube Q11 is connected to the positive line of the power supply equipment as the positive line of the input power supply; the source of the MOS tube Q11 is connected to the positive line of the power load through the sampling resistor R11; the two signal ends of the sampling resistor R11 serve as the two input ends of the signal amplification circuit, and the drain of the MOS tube Q11 is also connected to the power supply return line through the reverse diode D11.

[0014] As a further improvement of the present invention, the signal amplifying circuit includes a front-stage signal amplifying circuit and a rear-stage signal amplifying circuit.

[0015] As a further improvement of the present invention, the pre-stage signal amplification circuit includes a resistor R21, a resistor R22, a resistor R23, a resistor R24, an operational amplifier U21, and a capacitor C21; one end of the resistor R21 and the resistor R22 are respectively connected to the two ends of the sampling resistor R11 in the power switching circuit, and the other ends of the resistor R21 and the resistor R22 are respectively connected to the in-phase end and the inverting end of the operational amplifier U21, and the in-phase end of the operational amplifier U21 is connected to the control ground through the resistor R23, and the inverting end of the operational amplifier U21 is respectively connected to its output end through the resistor R24 ​​and the capacitor C21, and the output end of the operational amplifier U21 serves as the output end of the pre-stage signal amplification circuit.

[0016] As a further improvement of the present invention, the post-stage signal amplification circuit includes resistor R25, resistor R26, resistor R27, operational amplifier U22, and capacitor C22; the output end of the pre-stage signal amplification circuit is connected to the in-phase end of the operational amplifier U22 via resistor R25, the inverting end of the operational amplifier U22 is connected to the control ground via resistor R26, and the inverting end of the operational amplifier U22 is connected to its output end via resistor R27 and capacitor C22, and the output end of the operational amplifier U22 serves as the input end of the logic judgment circuit.

[0017] As a further improvement of the present invention, the logic judgment circuit includes a resistor R31, a resistor R32, a resistor R33, a resistor R34, a resistor R35, a capacitor C31, a voltage-stabilizing diode D31, a comparator U31 and a trigger U32; the output end of the signal amplification circuit is connected to the in-phase end of the comparator U31 through the resistor R31, and the in-phase end of the comparator U31 is connected to its output through the resistor R33; the inverting end of the comparator U31 is connected to the control power supply VCC through the resistor R32, and the inverting end of the comparator U31 is connected to the control ground through the voltage-stabilizing diode D31; the output end of the comparator U31 is connected to the S end of the trigger U32 and is connected to the control power supply VCC through the resistor R34; the R end of the trigger U32 is connected to the control power supply VCC through the capacitor C31 and is connected to the control ground through the resistor R35; the Q output end of the trigger U32 is connected to an input end of the soft-start drive circuit.

[0018] As a further improvement of the present invention, the soft start drive circuit includes a resistor R51, a resistor R52, a resistor R53, a resistor R54, a resistor R55, a resistor R56, a resistor R59, a resistor R58, a resistor R59, a capacitor C51, a capacitor C52, a diode D51, a diode D52, a diode D53, a voltage regulator diode D54, a diode D55, a diode D56, a transistor Q51, a transistor Q52, and a MOS tube Q53; the diode D52, The anode of the diode D51 is respectively the two input ends of the soft start driving circuit, the cathode of the diode D52 and the cathode of the diode D51 are connected together, and the bases of the transistors Q51 and Q52 are connected through a parallel circuit of a resistor R51 and a capacitor C51, and the bases of the transistors Q51 and Q52 are connected to the control ground through the resistor R52; the collector of the transistor Q51 is connected to the control power supply VCC through the resistor R53, and the emitter of the transistor Q52 is connected to the control ground. The emitter of the transistor Q51 and the emitter of the transistor Q52 are connected together, and connected to the gate of the MOS transistor Q53 through a resistor R54. The gate of the MOS transistor Q53 is also connected to the control ground through a resistor R55, and the source of the MOS transistor Q53 is connected to the control ground; the anode of the diode D53 is connected to the control power supply VCC, and the cathode of the diode D53 is connected to the drain of the MOS transistor Q53 through a resistor R56; the drain of the MOS transistor Q53 is connected to the control ground through a voltage stabilizing diode, and the drain of the MOS transistor Q53 is connected to the gate of the MOS transistor Q11 in the power switch circuit through a resistor R58, and the gate of the MOS transistor Q11 is connected to the source of the MOS transistor Q11 through a resistor R59; the anode of the diode D55 is connected to the drain of Q53, the cathode of the diode D55 is connected to the control ground through a capacitor C52, and the cathode of the diode D55 is also connected to the control power supply VCC through a parallel circuit of a diode D56 and a resistor R57.

[0019] As a further improvement of the present invention, the starting sealing circuit includes a resistor R41, a resistor R42, a capacitor C41 and a trigger U41; the S end of the trigger U41 is connected to the control power supply VCC through the capacitor C41, and the S end of the trigger U41 is connected to the control ground through the resistor R42; the R end of the trigger U41 is connected to the control power supply VCC through the resistor R41, and the Q output end of the trigger U41 is connected to another input end of the soft start drive circuit.

[0020] The function of the startup sealing circuit is that during the circuit startup process, within the sealing time t=1.2*R42*C41, the MOS tube Q11 of the power switch circuit is not controlled by the logic judgment circuit, but is always in a disconnected state, so as to prevent the MOS tube Q11 of the power switch circuit from oscillating frequently due to timing errors in the startup process; after the sealing time, the MOS tube Q11 is controlled by the logic judgment circuit.

[0021] As a further improvement of the present invention, the internal power supply of the power distribution circuit is provided by VCC, and the voltage amplitude of VCC relative to the control ground is 12V.

[0022] Furthermore, when the control power supply VCC is not started, the power distribution circuit does not work and the power supply link is disconnected; after the control power supply VCC is started, the power distribution circuit can work normally. After the power load short-circuit fault occurs, the power distribution circuit is restarted by powering off and powering on the power supply VCC; if the fault is not eliminated, the power supply link will be cut off again, and if the fault is eliminated, the power supply link can be connected normally.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] First, the technical solution of the present invention has a simple circuit structure, has short-circuit protection and on-off control functions, and has a surge current suppression function at the moment of connection. It can replace the three-part circuit of fuse, relay and surge suppression in the traditional satellite power distribution branch, and solves the problem of difficulty in selecting aerospace-grade components of large current fuses and relays. After the protection occurs, the circuit can be restarted, and if the short-circuit fault is eliminated, the power load can be powered normally, avoiding the problem that the power load cannot be powered after the fault recovery of the traditional satellite power distribution circuit; the circuit adopts peak current control, and the power switch voltage drop and power consumption are small at the moment of short circuit, which makes up for the defect that the solid-state current limiting protector cannot be used in high-voltage and high-power occasions.

[0025] Second, the technical solution of the present invention has a short circuit response time and a controllable short-circuit current peak value, which will not cause breakdown damage to the devices in the power supply link of the power supply equipment and the power-consuming equipment; the power supply bus voltage drops less than 1V at the moment of short circuit, which will not affect the quality of the power supply bus, and has no effect on the operation of other power loads during the short circuit; the devices used are easy to obtain aerospace-grade devices, and are suitable for aerospace high-power power distribution occasions. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 The present invention is a schematic diagram of the structure of a short-circuit protection circuit for a switching power supply in the prior art.

[0027] Figure 2 The figure is a schematic diagram of the structure of a power distribution circuit with short-circuit protection function according to the present invention.

[0028] Figure 3 The present invention is a circuit diagram of a power distribution circuit with a short-circuit protection function. DETAILED DESCRIPTION

[0029] The preferred embodiments of the present invention are described in further detail below.

[0030] like Figure 2As shown, the power distribution circuit with short-circuit protection function of the embodiment of the present invention includes a signal amplification circuit, a logic judgment circuit, a soft-start drive circuit, a start-up sealing circuit and a power switch circuit. The power input end of the power switch circuit is connected to the power supply equipment, the power output end of the power switch circuit is connected to the power load, the signal output end of the power switch circuit is connected to the input end of the signal amplification circuit, the signal amplification circuit, the logic judgment circuit, and the soft-start drive circuit are connected in sequence, the output end of the start-up sealing circuit is connected to another input end of the soft-start drive circuit, and the output end of the soft-start drive circuit is connected to the signal input end of the power switch circuit.

[0031] like Figure 3 As shown, the power switch circuit includes a resistor R11, a MOS tube Q11 and a diode D11. The drain of the MOS tube Q11 is the input power supply positive line, connected to the positive line of the power supply equipment, and the source of the MOS tube is connected to the positive line of the power load through the sampling resistor R11. The two signal ends of the sampling resistor R11 serve as the two input ends of the signal amplification circuit, and the drain of the MOS tube Q11 is also connected to the power supply return line through the reverse diode D11. At the moment when Q11 is disconnected, the current with a high slope will generate a large voltage spike on the parasitic inductance of the line, and the diode D11 can play a role in suppressing the voltage spike. The resistor R11 preferably uses a small resistance, low temperature drift, and high precision four-terminal sampling resistor.

[0032] like Figure 3 As shown, the signal amplification circuit includes two stages of operation circuits: the front-stage signal amplification circuit includes resistor R21, resistor R22, resistor R23, resistor R24, operational amplifier U21, and capacitor C21. One end of resistor R21 and resistor R22 are respectively connected to the two ends of the four-terminal sampling resistor R11 in the power switch circuit, and the other ends of resistor R21 and resistor R22 are respectively connected to the in-phase end and the inverting end of the operational amplifier U21, the in-phase end of the operational amplifier U21 is connected to the control ground FGND through resistor R23, and the inverting end of the operational amplifier U21 is connected to its output end through resistor R24 ​​and capacitor C21, and the output end of the operational amplifier U21 is used as the output end of the front-stage signal amplification circuit. The rear-stage signal amplification circuit includes resistor R25, resistor R26, resistor R27, operational amplifier U22, and capacitor C22. The output end of the pre-stage signal amplifier circuit is connected to the in-phase end of the operational amplifier U22 through the resistor R25, and the inverting end of the operational amplifier is connected to the control ground FGND through the resistor R26, and is connected to its output end through the parallel circuit of the resistor R27 and the capacitor C22. The output end of the operational amplifier U22 serves as the input end of the logic judgment circuit.

[0033] In this technical solution, the front-stage signal amplifier circuit adopts a differential proportional operation with strong resistance to common-mode noise energy. Preferably, the resistance values ​​of resistors R21 and R22 are equal, and the resistance values ​​of resistors R23 and R24 are equal. Both are high-precision, low-temperature drift resistors. The relationship between the output voltage Vout1 of the front-stage signal amplifier circuit and the current I flowing through the distribution circuit is: Vout1 = I*R11*R24 / R22. The rear-stage signal amplifier circuit is used for high-multiple proportional amplification, and the relationship between its output voltage Vout2 and the front-stage output voltage Vout1 is: Vout2 = (1+R27 / R26)*Vout1. Therefore, the relationship between the output voltage Vout2 of the signal amplifier circuit and the current I flowing through the distribution circuit is: Vout2 = (1+R27 / R26)*I*R11*R24 / R22. Op amps U21 and U22 are selected as low-noise, high-bandwidth, and high-slew rate types. Capacitors C21 and C22 are zero-point compensation capacitors.

[0034] like Figure 3 As shown, the logic judgment circuit includes a resistor R31, a resistor R32, a resistor R33, a resistor R34, a resistor R35, a capacitor C31, a voltage stabilizing diode D31, a comparator U31 and a trigger U32. The input end of the logic judgment circuit is connected to the in-phase end of the comparator U31 through the resistor R31, and the in-phase end of U31 is connected to its output through the resistor R33. The inverting end of the comparator U31 is connected to the control power supply VCC through the resistor R32, and is connected to the control ground FGND through the voltage stabilizing diode D31. The output end of the comparator U31 is connected to the S end of the trigger U32, and is connected to the control power supply VCC through the resistor R34. The R end of the trigger U32 is connected to the control power supply VCC through the capacitor C31, and is connected to the control ground FGND through the resistor R35. The Q output end of the trigger U32 is connected to an input end of the soft start drive circuit.

[0035] The voltage zener diode D31 provides a protection reference voltage value Vref. When the voltage at the in-phase terminal of the comparator U31 is higher than Vref, the output terminal of U31 flips. The short-circuit protection current peak ILIM can be calculated as:

[0036] like Figure 3As shown, the soft start driving circuit includes resistor R51, resistor R52, resistor R53, resistor R54, resistor R55, resistor R56, resistor R59, resistor R58, resistor R59, capacitor C51, capacitor C52, signal diode V51, signal diode V52, signal diode V53, voltage stabilizing diode V54, signal diode V55, signal diode V56, transistor Q51, transistor Q52, and MOS transistor Q53. The anodes of diodes D52 and D51 are respectively the two inputs of the soft start driving circuit, and the cathodes of the two are connected together, and connected to the bases of transistors Q51 and Q52 through resistor R51 and capacitor C51, and the base is also connected to the control ground FGND through resistor R52. The collector of transistor Q51 is connected to the control power supply VCC through resistor R53, and the emitter of transistor Q52 is connected to the control ground FGND. The emitter of transistor Q51 and the emitter of Q52 are connected together, and connected to the gate of MOS tube Q53 through resistor R54. The gate of Q53 is also connected to the control ground FGND through resistor R55, and the source of Q53 is also connected to the control ground FGND. The anode of diode D53 is connected to the control power supply VCC, and the cathode is connected to the drain of MOS tube Q53 through resistor R56. The drain of Q53 is also connected to the control ground FGND through a voltage-stabilizing diode, and is connected to the gate of Q11 in the power switch circuit through resistor R58. The gate of Q11 is connected to the source of Q11 through resistor R59. The anode of diode D55 is connected to the drain of Q53, and the cathode is connected to the control ground FGND through C52, and is connected to the control power supply VCC through the parallel circuit of diode D56 and resistor R57. The diodes D55, D56, resistors R56, R57, R58 and capacitor C52 form a soft start circuit. When the circuit is powered on, capacitor C52 is slowly charged, and the voltage across R59, i.e., the gate-source voltage of MOS tube Q11, slowly increases, so that Q11 works in the linear resistance area, which suppresses the surge current at the moment of power on. After normal power on, C52 is fully charged and Q11 works in the on state.

[0037] like Figure 3 As shown, the startup sealing circuit includes a resistor R41, a resistor R42, a capacitor C41 and a trigger U41. The S terminal of the trigger U41 is connected to the control power supply VCC through the capacitor C41, and is connected to the control ground FGND through the resistor R42. The R terminal of the trigger U41 is connected to the control power supply VCC through the resistor R41, and the Q output terminal of the trigger U41 is connected to another input terminal of the soft start drive circuit. The function of the startup sealing circuit is that during the circuit startup process, within the sealing time t=1.2*R42*C41, the MOS tube Q11 of the power switch circuit is not controlled by the logic judgment circuit, but is always in the disconnected state, so as to prevent the timing error of the startup process from causing the MOS tube Q11 of the power switch circuit to frequently oscillate and cause over-power damage; after the sealing time, the MOS tube Q11 is controlled by the logic judgment circuit to be turned on or off.

[0038] The power supply of the internal chip of the power distribution circuit with short-circuit protection function in the embodiment of the present invention is provided by VCC, and the voltage amplitude of VCC relative to the control ground FGND is 12V. When the control power supply VCC is not started, the power distribution circuit does not work and the power supply link is in a disconnected state. After the control power supply VCC is started, the power distribution circuit can work normally. After the power load short-circuit fault, the power distribution circuit is restarted by powering off and powering on the power supply VCC. If the fault is not eliminated, the power supply link will be cut off again. If the fault is eliminated, the power supply link can be connected normally.

[0039] The above contents are further detailed descriptions of the present invention in combination with specific preferred embodiments, and it cannot be determined that the specific implementation of the present invention is limited to these descriptions. For ordinary technicians in the technical field to which the present invention belongs, several simple deductions or substitutions can be made without departing from the concept of the present invention, which should be regarded as falling within the protection scope of the present invention.

Claims

1. A power distribution circuit with short-circuit protection function, characterized in that: It includes a power switch circuit, a signal amplifying circuit, a logic judgment circuit, a soft start driving circuit and a start sealing circuit; the power input end of the power switch circuit is connected to the power supply equipment, and the power output end of the power switch circuit is connected to the power load; the signal output end of the power switch circuit is connected to the input end of the signal amplifying circuit, the output end of the signal amplifying circuit is connected to one input end of the soft start driving circuit through the logic judgment circuit, the output end of the start sealing circuit is connected to the other input end of the soft start driving circuit, and the output end of the soft start driving circuit is connected to the signal input end of the power switch circuit; The soft start driving circuit includes a resistor R51, a resistor R52, a resistor R53, a resistor R54, a resistor R55, a resistor R56, a resistor R59, a resistor R58, a resistor R59, a capacitor C51, a capacitor C52, a diode D51, a diode D52, a diode D53, a voltage stabilizing diode D54, a diode D55, a diode D56, a transistor Q51, a transistor Q52, and a MOS transistor Q53; the anodes of the diodes D52 and D51 They are two input ends of the soft start drive circuit respectively, the cathode of the diode D52 and the cathode of the diode D51 are connected together, and the bases of the transistors Q51 and Q52 are connected through a parallel circuit of a resistor R51 and a capacitor C51, and the bases of the transistors Q51 and Q52 are connected to the control ground through the resistor R52; the collector of the transistor Q51 is connected to the control power supply VCC through the resistor R53, and the emitter of the transistor Q52 is connected to the control ground; the transistors The emitter of the transistor Q51 and the emitter of the triode Q52 are connected together, and connected to the gate of the MOS transistor Q53 through a resistor R54. The gate of the MOS transistor Q53 is also connected to the control ground through a resistor R55, and the source of the MOS transistor Q53 is connected to the control ground; the anode of the diode D53 is connected to the control power supply VCC, and the cathode of the diode D53 is connected to the drain of the MOS transistor Q53 through a resistor R56; the drain of the MOS transistor Q53 is connected to the control ground through a voltage stabilizing diode, and the drain of the MOS transistor Q53 is connected to the gate of the MOS transistor Q11 in the power switch circuit through a resistor R58, and the gate of the MOS transistor Q11 is connected to the source of the MOS transistor Q11 through a resistor R59; the anode of the diode D55 is connected to the drain of Q53, the cathode of the diode D55 is connected to the control ground through a capacitor C52, and the cathode of the diode D55 is also connected to the control power supply VCC through a parallel circuit of a diode D56 and a resistor R57.

2. The power distribution circuit with short-circuit protection function according to claim 1, characterized in that: The power switch circuit includes a sampling resistor R11, a MOS tube Q11 and a diode D11; the drain of the MOS tube Q11 is connected to the positive line of the power supply device as the positive line of the input power supply; the source of the MOS tube Q11 is connected to the positive line of the power load through the sampling resistor R11; the two signal ends of the sampling resistor R11 serve as the two input ends of the signal amplification circuit, and the drain of the MOS tube Q11 is also connected to the power supply return line through the reverse diode D11.

3. The power distribution circuit with short-circuit protection function according to claim 2, characterized in that: The signal amplifying circuit comprises a front-stage signal amplifying circuit and a rear-stage signal amplifying circuit.

4. The power distribution circuit with short-circuit protection function according to claim 3, characterized in that: The front-stage signal amplification circuit includes a resistor R21, a resistor R22, a resistor R23, a resistor R24, an operational amplifier U21, and a capacitor C21; one end of the resistor R21 and the resistor R22 are respectively connected to the two ends of the sampling resistor R11 in the power switch circuit, and the other ends of the resistor R21 and the resistor R22 are respectively connected to the in-phase end and the inverting end of the operational amplifier U21, and the in-phase end of the operational amplifier U21 is connected to the control ground through the resistor R23, and the inverting end of the operational amplifier U21 is connected to its output end through the resistor R24 ​​and the capacitor C21, and the output end of the operational amplifier U21 serves as the output end of the front-stage signal amplification circuit.

5. The power distribution circuit with short-circuit protection function according to claim 4, characterized in that: The post-stage signal amplification circuit includes resistor R25, resistor R26, resistor R27, operational amplifier U22, and capacitor C22; the output end of the pre-stage signal amplification circuit is connected to the in-phase end of the operational amplifier U22 via resistor R25, the inverting end of the operational amplifier U22 is connected to the control ground via resistor R26, and the inverting end of the operational amplifier U22 is connected to its output end via resistor R27 and capacitor C22 respectively, and the output end of the operational amplifier U22 serves as the input end of the logic judgment circuit.

6. The power distribution circuit with short-circuit protection function according to claim 5, characterized in that: The logic judgment circuit includes a resistor R31, a resistor R32, a resistor R33, a resistor R34, a resistor R35, a capacitor C31, a voltage stabilizing diode D31, a comparator U31 and a trigger U32; the output end of the signal amplification circuit is connected to the in-phase end of the comparator U31 through the resistor R31, and the in-phase end of the comparator U31 is connected to its output through the resistor R33; The inverting end of the comparator U31 is connected to the control power supply VCC through the resistor R32, and the inverting end of the comparator U31 is connected to the control ground through the voltage stabilizing diode D31; the output end of the comparator U31 is connected to the S end of the trigger U32, and is connected to the control power supply VCC through the resistor R34; the R end of the trigger U32 is connected to the control power supply VCC through the capacitor C31, and is connected to the control ground through the resistor R35; the Q output end of the trigger U32 is connected to an input end of the soft start drive circuit.

7. The power distribution circuit with short-circuit protection function according to claim 6, characterized in that: The startup sealing circuit includes a resistor R41, a resistor R42, a capacitor C41 and a trigger U41; the S end of the trigger U41 is connected to the control power supply VCC through the capacitor C41, and the S end of the trigger U41 is connected to the control ground through the resistor R42; the R end of the trigger U41 is connected to the control power supply VCC through the resistor R41, and the Q output end of the trigger U41 is connected to another input end of the soft start drive circuit.

8. The power distribution circuit with short-circuit protection function according to any one of claims 1 to 7, characterized in that: The internal power supply of the distribution circuit is provided by the VCC of the power supply, and the voltage amplitude of VCC relative to the control ground is 12V; when the control power supply VCC is not started, the distribution circuit does not work and the power supply link is disconnected; after the control power supply VCC is started, the distribution circuit can work normally; after the power load short-circuit fault, the distribution circuit is restarted by powering off and powering on the power supply VCC; If the fault is not eliminated, the power supply link will be cut off again. If the fault is eliminated, the power supply link can be connected normally.

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