Input voltage power failure locking and startup and shutdown instruction control circuit and working method thereof

Abstract

The invention relates to an input voltage power failure locking and startup and shutdown instruction control circuit and a working method thereof. The circuit comprises a short circuit protection unit, a surge suppression unit, an EMI filtering unit, a DC / DC conversion unit, an output filtering unit and a control circuit unit. The control circuit unit comprises an input bus power failure locking unit, a shutdown control instruction unit, a startup control instruction unit and a startup and shutdown state locking unit. The method is suitable for a power supply and distribution system in aerospace electronic equipment, and can be widely applied to other various power supply and distribution systems which work reliably for a long time. According to the method, the reliability of pulse instruction control on and off of the power supply and distribution system in the electronic equipment for space navigation can be guaranteed, when the primary input bus voltage breaks down or returns to normal, the power supply can be effectively in the off state, the effective on and off instruction can be retransmitted through the platform, and it is guaranteed that the system is reliably restarted and operated.

Description

Technical Field

[0001] The present invention relates to the technical field of switching power supplies and power supply and distribution systems, and in particular to an input voltage power-off locking and power on / off command control circuit and a working method thereof. Background Art

[0002] The power supply and distribution system of electronic equipment is usually composed of a multi-output switching power supply and a control function circuit. Its main function is to realize the isolation and conversion of the primary power supply into various voltages required for the power supply of electronic equipment, while meeting the requirements of the power supply of electronic equipment, such as the on / off pulse command control and the input bus voltage power-off locking.

[0003] The power supply and distribution system for aerospace electronic equipment usually designs two sets of control instructions, namely the power-on pulse instruction and the power-off pulse instruction. The instructions control the switching power supply to provide the required voltage and current for the electronic equipment. The power-on and power-off instructions for aerospace electronic equipment usually include TTL level instructions and power-on and power-off pulse instructions, which are set by the aerospace electronic equipment platform. In order to reduce the loss of instruction control and improve the anti-interference ability, the system adopts a specific pulse instruction, which has the characteristics of voltage amplitude of 28V, pulse width of 80ms, drive current of 10mA, and is isolated from the primary power supply ground and the secondary power supply ground. When realizing the power-on / power-off control, the power-on and power-off instructions are in the form of pulses, and the magnetic latching relay design scheme is usually adopted. However, due to the characteristics of the magnetic latching relay coil and the mechanical structure of the contact, the initial state of the magnetic latching relay contact is prone to be normally open and normally closed, and the contact state may change when it is affected by force during the launch or transportation process. Therefore, in aerospace electronic equipment, optocouplers and control MOS tube design schemes are used to achieve more reliable control.

[0004] During the operation of the power supply and distribution system for aerospace electronic equipment, if other related electronic equipment fails, resulting in a low input voltage bus voltage or a fault problem, all power outputs need to be turned off and the system is in a shutdown state. The platform needs to resend the power-on command to restart the system. Although this processing method helps prevent further damage, it also has some potential technical defects: (1) Response time delay: It may take a certain amount of time from detecting the problem to completely shutting down all power outputs. During this time, the electronic equipment may suffer a certain degree of damage. (2) Data loss risk: If the system is forced to shut down without sufficient time to perform normal data saving operations, it may cause unsaved data to be lost or the file system to be damaged. (3) Complexity of the restart process: Restarting the entire system involves multiple steps, including but not limited to resetting the status of each component and reloading the configuration. Errors may occur in this process, affecting the reliability of the system. (4) Dependence on external intervention: The system must wait for the platform to resend the power-on command before it can start, which increases the reliance on the reliability of human operation or automated control systems. (5) Difficult diagnosis: Simply cutting off the power supply does not help quickly locate the problem. In the absence of sufficient records, it will become more difficult to analyze the cause of the failure. (6) Impact of unstable power supply: Frequent switching of power supply may have a negative impact on certain sensitive components and shorten their service life.

[0005] Therefore, it is necessary to implement an input voltage power-off lock and power-on / off command control circuit for improving the power supply reliability of the power supply and distribution system in aerospace electronic equipment. Summary of the invention

[0006] In order to solve the deficiencies in the prior art, the object of the present invention is to provide an input voltage power-off lockout and power-on / off command control circuit and a working method thereof for improving the power supply reliability of a power supply and distribution system in aerospace electronic equipment.

[0007] To achieve the above object, the present invention adopts the following technical solutions:

[0008] An input voltage power-off lockout and power-on / off command control circuit includes a short circuit protection unit, a surge suppression unit, an EMI filter unit, a DC / DC conversion unit, an output filter unit, and a control circuit unit. The control circuit unit includes an input bus power-off lockout unit, a shutdown control command unit, a startup control command unit, and a power-on / off state lockout unit.

[0009] The short-circuit protection unit is used to protect the primary power supply; the surge suppression unit is used to suppress the surge current generated by the subsequent capacitor and the load; the EMI filter unit is used to suppress the reflected ripple voltage of the DC / DC conversion unit, and at the same time suppress the conducted interference, and input power to the DC / DC conversion unit; the DC / DC conversion unit is used to output the power supply requirements of different voltages and powers of the load; the control circuit unit is used to control the DC / DC conversion unit to start and stop, and when the input bus loses power, control the DC / DC conversion unit to shut down.

[0010] Preferably according to the present invention, the input bus power-off locking unit includes a resistor R1, a resistor R2, a resistor R3, a voltage regulator tube V1, a resistor R4, a diode V2, an operational amplifier N1, a resistor R7, a resistor R8, a capacitor C1 and a transistor V5.

[0011] Specifically, the first end of the resistor R1 is connected to the positive electrode of the input bus, and the second end of the resistor R1 is respectively connected to the first end of the resistor R2 and the reverse end of the operational amplifier N1; the second end of the resistor R2 is grounded; the first end of the resistor R3 is connected to the positive electrode of the input bus, and the second end of the resistor R3 is respectively connected to the negative electrode of the voltage regulator tube V1, the positive end of the operational amplifier N1, and the first end of the resistor R4; the positive electrode of the voltage regulator tube V1 is grounded; the first end of the resistor R4 is also connected to the positive end of the operational amplifier N1, the second end of the resistor R4 is connected to the negative electrode of the diode V2, and the positive electrode of the diode V2 is connected to the output end of the operational amplifier N1; the output end of the operational amplifier N1 is also connected to the first end of the resistor R7, and the second end of the resistor R7 is respectively connected to the first end of the resistor R8, the first end of the capacitor C1, and the base of the transistor V5; the second end of the resistor R8, the second end of the capacitor C1, and the emitter of the transistor V5 are all grounded.

[0012] Preferably, according to the present invention, the shutdown control command unit includes an optical coupler N2, a resistor R5 and a diode V3; the optical coupler N2 includes a first light emitting diode and a first phototransistor.

[0013] Specifically, the first end of the resistor R5 is connected to the shutdown command signal, the second end of the resistor R5 is connected to the positive electrode of the diode V3, the negative electrode of the diode V3 is connected to the positive electrode of the first light-emitting diode, and the negative electrode of the first light-emitting diode is grounded; the collector of the first phototransistor is connected to the collector of the transistor V5, and the emitter of the first phototransistor is grounded.

[0014] Preferably according to the present invention, the power-on control command unit includes an optocoupler N3, a resistor R6, a diode V4 and a resistor R9; the optocoupler N3 includes a second light-emitting diode and a second phototransistor; the first end of the resistor R6 is connected to the power-on command signal, the second end of the resistor R6 is connected to the positive electrode of the diode V4, the negative electrode of the diode V4 is connected to the positive electrode of the first light-emitting diode, and the negative electrode of the second light-emitting diode is grounded; the collector of the second phototransistor is connected to the first end of the resistor R9, and the emitter of the second phototransistor is connected to the collector of the transistor V5; the second end of the resistor R9 is connected to the positive electrode of the input bus.

[0015] Preferably, according to the present invention, the power on / off state locking unit comprises an optical coupler N4, a resistor R10 and a resistor R11; the optical coupler N4 comprises a third light emitting diode and a third phototransistor;

[0016] The first end of the resistor R10 and the first end of the resistor R11 are both connected to the positive electrode of the input bus; the second end of the resistor R10 is connected to the collector of the third phototransistor, and the emitter of the third phototransistor is connected to the collector of the transistor V5; the second end of the resistor R11 is connected to the positive electrode of the third light-emitting diode.

[0017] Preferably, according to the present invention, the surge suppression control unit includes a resistor R12, a voltage regulator tube V6, a transistor V7, a capacitor C2, a resistor R13, a voltage regulator tube V8 and a MOS tube V9;

[0018] The first end of the resistor R12 is connected to the positive electrode of the input bus, and the second end of the resistor R12 is connected to the collector of the transistor V7; the base of the transistor V7 is connected to the negative electrode of the voltage regulator tube V6, and the positive electrode of the voltage regulator tube V6 is grounded; the emitter of the transistor V7 is connected to the first end of the capacitor C2, and the second end of the capacitor C2 is grounded; the first end of the resistor R13 is connected to the emitter of the transistor V7, the second end of the resistor R13 is connected to the first end of the capacitor C3, and the second end of the capacitor C3 is grounded; the negative electrode of the voltage regulator tube V8 is respectively connected to the first end of the capacitor C3, the gate of the MOS tube V9 is connected to the negative electrode of the voltage regulator tube V8, the source of the MOS tube V9 is grounded, and the drain of the MOS tube V9 is connected to the input negative end of the EMI filter unit; the input positive end of the EMI filter unit is connected to the positive electrode of the input bus.

[0019] The present invention also includes a working method of an input voltage power-off locking and power-on / off command control circuit, which is implemented by using the above-mentioned input voltage power-off locking and power-on / off command control circuit, and includes the following steps:

[0020] S1. The power-on / off state locking unit is controlled by the power-on command. When the power-on command gives a pulse level, the optocoupler N4 in the power-on / off state locking unit is turned on, and at the same time, the transistor V7 in the surge suppression circuit is turned on, the MOS tube V9 is turned on, and each DC / DC output voltage is normal; when the power-off command gives a pulse level, the transistor V7 in the surge suppression circuit is turned off, and at the same time, the optocoupler N4 in the power-on / off state locking unit is turned off, the MOS tube V9 is turned off, and the output voltage of each DC / DC is turned off;

[0021] S2. When the input voltage bus is undervoltage or powered off, the detection voltage of the voltage divider resistor R1 and the voltage divider resistor R2 is lower than the threshold voltage of the op amp in-phase terminal, the op amp output is high level, the transistor V5 is turned on, the transistor V7 is turned off, and the optocoupler N4 in the switch state locking circuit is turned off, and the DC / DC output voltages of each channel are turned off;

[0022] S3, when the input voltage bus voltage is restored, since the optocoupler N4 in the switch state locking circuit is in the off state, each DC / DC output voltage is in the off state;

[0023] S4. When there is a power-on command, each DC / DC output voltage works normally.

[0024] Compared with the prior art, the advantages of the present invention are:

[0025] (1) The circuit with input bus power-off locking and power-on / off pulse command control functions described in the present invention is suitable for power supply and distribution systems in aerospace electronic equipment, and can be widely used in various other types of power supply and distribution systems with long-term reliability. The present invention can ensure the reliability of pulse command control power on / off in the power supply and distribution system of aerospace electronic equipment. When the input bus voltage fails or returns to normal, the power supply can be effectively turned off, and the platform can resend effective power on / off commands to ensure reliable restart of the system.

[0026] (2) The present invention adopts an input bus power-off locking unit, a shutdown control command unit, a startup control command unit, a power-on / off state locking unit, and a surge suppression control unit, which can realize the power-on / off pulse command control of the power distribution system and the input bus voltage power-off locking. It has the characteristics of simple circuit, improved reliability of the power supply system and long life, and can be widely used in the field of switching power supplies and power distribution systems. The present invention controls the input bus voltage through the power MOS tube V9, and through the power-on / off pulse command unit, the optical coupler in the startup control command unit or the shutdown control command unit is turned on, and the pulse signal is sent to the subsequent module through the power-on / off state locking unit to keep the startup or shutdown state locked, so that the power MOS tube V9 is always in the on or off state. When the power MOS tube V9 is in the on state, each DC / DC outputs a normal voltage. When the power MOS tube V9 is in the off state, each DC / DC turns off the output voltage. By controlling the power MOS tube V9, the input bus voltage is controlled, which has the advantage of small bus current. At the same time, when a fault occurs, the response speed is fast and the damage to the subsequent devices is small. The core technology of the present invention is the power on / off state locking, and the design of a relatively simple and reliable circuit effectively meets the system pulse instruction requirements. At the same time, when the primary power supply fails or restores normal voltage, the system instruction can be used to control the power-on operation of the subsequent circuit.

[0027] (3) The present invention gives priority to circuit failure problems caused by single particles and total doses in the aerospace environment in circuit design, and uses devices that are sensitive to single particles and total doses, which are more reliable in aerospace applications. Due to the problems affecting the service life of relays, large driving currents, and installation direction requirements, the present invention uses optocouplers to replace relays in the prior art, which have the advantages of long service life and low driving current. By designing an optocoupler isolation circuit, the mutual interference between the primary power supply, the secondary power supply and the control instructions can be effectively isolated, thereby improving the reliability of instruction control. By designing the input bus voltage sampling circuit as a comparison circuit with a hysteresis window, the malfunction problem caused by input voltage jitter can be effectively suppressed. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is the principle frame of the input voltage power-off lock and power on / off command control circuit in the present invention. Figure 1 ;

[0029] Figure 2 This is the principle frame of the input voltage power-off lock and power on / off command control circuit in the present invention. Figure 2 ;

[0030] Figure 3 It is a circuit principle diagram of the input voltage power-off lock and power on / off command control circuit in the present invention.

[0031] in:

[0032] 1. Short circuit protection unit, 2. Surge suppression unit, 3. EMI filter unit, 4. DC / DC conversion unit, 5. Output filter unit, 6. Control circuit unit, 7. Input bus power-off locking unit, 8. Shutdown control command unit, 9. Startup control command unit, 10. Power on / off state locking unit. DETAILED DESCRIPTION

[0033] The present invention will be further described below in conjunction with the accompanying drawings:

[0034] like Figure 1 The input voltage power-off lockout and power-on / off command control circuit shown in the figure includes a short circuit protection unit 1, a surge suppression unit 2, an EMI filter unit 3, a DC / DC conversion unit 4, an output filter unit 5 and a control circuit unit 6. This design ensures the safe operation of the power supply and distribution system, can protect the equipment under abnormal conditions, and can manage the power supply status through precise control signals.

[0035] The input DC voltage passes through the short circuit protection unit 1 to protect the primary power supply. When a short circuit occurs in the circuit, the short circuit protection unit 1 can quickly cut off the power supply to prevent excessive current from damaging the circuit or causing a fire. Usually, a fuse, a circuit breaker or an electronic protection circuit (such as a MOSFET-based protection circuit) is used.

[0036] The surge suppression unit 2 is used to protect the circuit from transient overvoltage, such as lightning strikes or sudden voltage fluctuations in the power grid. The surge suppression unit 2 suppresses the surge current generated by the subsequent capacitor and the load.

[0037] The EMI filter unit 3 is used to reduce electromagnetic interference (EMI), including noise entering the system from the outside and emitted from the system, to maintain the purity of the signal, and can be implemented by an existing low-pass filter network. After the EMI filter unit 3, the reflected ripple voltage of the DC / DC conversion unit 4 is suppressed, and the conducted interference is suppressed, and the DC / DC conversion unit 4 is input with power.

[0038] The DC / DC conversion unit 4 is used to convert the input DC voltage into different levels of DC voltage suitable for the load. The DC / DC conversion unit 4 can be a buck type, a boost type, a buck-boost type or other types of DC / DC converters. In this embodiment, the DC / DC conversion unit 4 outputs the power supply requirements of different voltage powers of the load.

[0039] The output filter unit 5 is used to smooth the output voltage after DC / DC conversion, remove ripples and other high-frequency components, and provide a stable DC voltage to the load. It is generally implemented by an LC filter, that is, a filter network composed of an inductor and a capacitor.

[0040] The control circuit unit 6 is used to manage the entire power supply process, including the operation control of the DC / DC converter, voltage regulation, fault monitoring and response, and processing of the switch pulse command, which is the innovation of the present invention. In this embodiment, the DC / DC conversion unit 4 is controlled to start and shut down through the control circuit unit 6. At the same time, when the input bus loses power, the DC / DC conversion unit 4 can be effectively shut down to effectively and reliably supply power to the load. Preferably, the DC / DC conversion unit adopts a DC / DC converter.

[0041] like Figure 2 As shown, the control circuit unit 6 includes an input bus power-off locking unit 7 , a shutdown control command unit 8 , a startup control command unit 9 and a power-on / power-off state locking unit 10 .

[0042] like Figure 3 As shown, the input bus power-off locking unit 7 includes a resistor R1, a resistor R2, a resistor R3, a voltage regulator tube V1, a resistor R4, a diode V2, an operational amplifier N1, a resistor R7, a resistor R8, a capacitor C1 and a transistor V5.

[0043] Specifically, the first end of the resistor R1 is connected to the positive pole of the input bus, and the second end of the resistor R1 is respectively connected to the first end of the resistor R2 and the reverse end of the operational amplifier N1; the second end of the resistor R2 is grounded; the resistor R1 is used to sample the input bus voltage and input it into the reverse end of the operational amplifier N1. The first end of the resistor R3 is connected to the positive electrode of the input bus, and the second end of the resistor R3 is respectively connected to the negative electrode of the voltage regulator tube V1, the positive end of the operational amplifier N1, and the first end of the resistor R4; the positive electrode of the voltage regulator tube V1 is grounded; the resistor R3 is used to set a threshold voltage at the positive end of the operational amplifier N1; the first end of the resistor R4 is also connected to the positive end of the operational amplifier N1, the second end of the resistor R4 is connected to the negative electrode of the diode V2, and the positive electrode of the diode V2 is connected to the output end of the operational amplifier N1; the output end of the operational amplifier N1 is also connected to the first end of the resistor R7, and the second end of the resistor R7 is respectively connected to the first end of the resistor R8, the first end of the capacitor C1, and the base of the transistor V5; the second end of the resistor R8, the second end of the capacitor C1, and the emitter of the transistor V5 are all grounded.

[0044] The input bus power-off locking unit 7 is used to lock the system and shut down the power output when the input bus voltage is lower than a preset threshold. Among them, resistors R1 and R2 are voltage-dividing resistors, which form a voltage-dividing network for sampling the input bus voltage and sending the voltage to the reverse end of the operational amplifier N1. Resistor R3 and voltage-stabilizing tube V1 set a fixed threshold voltage at the positive end of the operational amplifier N1. When the input voltage is higher than the threshold, the operational amplifier N1 outputs a low level; when the input voltage is lower than the threshold or the power is off, the operational amplifier N1 outputs a high level. Resistor R7, resistor R8, and capacitor C1 are connected to the base of transistor V5 to control the conduction and shutdown of transistor V5. The output of the operational amplifier N1 drives the transistor V5 through the RC network composed of resistors R7, R8, and capacitor C1. When the operational amplifier N1 outputs a high level, the transistor V5 is turned on, thereby triggering the subsequent shutdown operation. The diode V2 and the resistor R4 are connected to the output terminal of the operational amplifier N1 to form a positive feedback loop, ensuring that once the power-off lock is triggered, the system will not automatically restart even if the input voltage is restored.

[0045] In this embodiment, the input bus power-off locking unit 7 samples the input voltage through the voltage-dividing resistors (R1, R2), and compares it with the threshold voltage through the operational amplifier N1, and the operational amplifier N1 outputs high and low levels. At the same time, the operational amplifier N1 is designed as a positive feedback circuit. When the input voltage is lower than the threshold voltage or the power is off, the operational amplifier N1 outputs a high level, or the surge suppression circuit 2 is in a closed state, so that each DC / DC turns off the output voltage, and the platform resends the power-on command, and each DC / DC outputs a normal voltage.

[0046] like Figure 3 As shown, the shutdown control command unit 8 includes an optical coupler N2, a resistor R5 and a diode V3; the optical coupler N2 includes a first light emitting diode and a first phototransistor.

[0047] Specifically, the first end of the resistor R5 is connected to the shutdown command signal, the second end of the resistor R5 is connected to the positive electrode of the diode V3, the negative electrode of the diode V3 is connected to the positive electrode of the first light-emitting diode, and the negative electrode of the first light-emitting diode is grounded; the collector of the first phototransistor is connected to the collector of the transistor V5, and the emitter of the first phototransistor is grounded. When the shutdown command gives a high level, the first light-emitting diode in the optical coupler N2 generates a photocurrent, the first phototransistor in the optical coupler N2 is turned on, and the output voltage of the optical coupler N2 is 0V.

[0048] The shutdown control command unit 8 is used to receive an external shutdown command and control the DC / DC conversion unit to shut down. When a high-level shutdown command is given externally, the first light-emitting diode in the optical coupler N2 is illuminated through the resistor R5 and the diode V3, thereby turning on the first phototransistor. After the first phototransistor is turned on, its collector is grounded, thereby pulling down the base of the transistor V5, causing the transistor V5 to be cut off, and shutting down the DC / DC conversion unit.

[0049] like Figure 3 As shown, the power-on control command unit 9 includes an optical coupler N3, a resistor R6, a diode V4 and a resistor R9; the optical coupler N3 includes a second light-emitting diode and a second phototransistor; the first end of the resistor R6 is connected to the power-on command signal, the second end of the resistor R6 is connected to the positive electrode of the diode V4, the negative electrode of the diode V4 is connected to the positive electrode of the first light-emitting diode, and the negative electrode of the second light-emitting diode is grounded; the collector of the second phototransistor is connected to the first end of the resistor R9, and the emitter of the second phototransistor is connected to the collector of the transistor V5; the second end of the resistor R9 is connected to the positive electrode of the input bus. The resistor R6 is used to limit the current flowing through the LED. The diode V4 is used to protect the LED from the influence of reverse voltage. The resistor R9 is a pull-up resistor, which is used to ensure that the collector of the phototransistor is at a high level when there is no input signal.

[0050] The power-on control command unit 9 is used to receive an external power-on command and control the DC / DC conversion unit to start. When a high-level power-on command is given externally, the second light-emitting diode in the optocoupler N3 is illuminated through the resistor R6 and the diode V4, thereby turning on the second phototransistor. After the second phototransistor is turned on, its collector is connected to the positive pole of the input bus through the resistor R9, providing a high level to the base of the transistor V5, so that the transistor V5 is turned on and the DC / DC conversion unit is turned on. When there is no power-on command signal, the voltage on the resistor R6 is 0V, so the second light-emitting diode in the optocoupler N3 does not emit light. Since the second light-emitting diode does not emit light, the second phototransistor in the optocoupler N3 is in a cut-off state. The resistor R9 pulls the collector of the phototransistor to a high level (close to the positive voltage of the input bus), so that the base of the transistor V5 also maintains a high level, thereby maintaining the off state.

[0051] like Figure 3 As shown, the power on / off state locking unit 10 includes an optical coupler N4, a resistor R10 and a resistor R11; the optical coupler N4 includes a third light emitting diode and a third phototransistor.

[0052] Specifically, the first end of the resistor R10 and the first end of the resistor R11 are both connected to the positive electrode of the input bus; the second end of the resistor R10 is connected to the collector of the third phototransistor, and the emitter of the third phototransistor is connected to the collector of the transistor V5. The second end of the resistor R11 is connected to the positive electrode of the third light-emitting diode. The resistor R10 is a pull-up resistor, which is used to ensure that the collector of the phototransistor is at a high level when there is no input signal. The resistor R11 is used to limit the current flowing through the LED.

[0053] The on / off state locking unit 10 is used to maintain the current on / off state to prevent accidental changes. When the MOS tube V9 is not turned on, the third light-emitting diode in the optocoupler N4 does not emit light. Since the third light-emitting diode does not emit light, the third phototransistor in the optocoupler N4 is in the cut-off state. The resistor R10 pulls the collector of the third phototransistor to a high level (close to the positive voltage of the input bus), so that the base of the transistor V5 also maintains a high level, thereby maintaining the off state. When the MOS tube V9 is turned on, the current flows to the third light-emitting diode in the optocoupler N4 through the resistor R11. The third light-emitting diode emits light, turning on the third phototransistor in the optocoupler N4. After the phototransistor is turned on, its collector is pulled low, and the output voltage of the optocoupler N3 is a high voltage, causing the base of the transistor V5 to be pulled low. The low level of the base of the transistor V5 turns it on, thereby triggering the subsequent power-on operation and turning on the DC / DC conversion unit.

[0054] The design of the switch state locking unit 10 uses the optical coupler N4 to achieve electrical isolation, and converts the conduction state of the MOS tube V9 into a signal that can control the conduction or cutoff of the triode V5 through the photoelectric effect. When the MOS tube V9 is turned on, the third light-emitting diode in the optical coupler N4 emits light, so that the third photosensitive triode is turned on, and then the base of the triode V5 is pulled down to turn it on, thereby starting the system. This design not only provides electrical isolation, but also enhances the anti-interference ability of the system. In addition, this design also has a locking function. Once the MOS tube V9 is turned on and triggers the optical coupler N4, even if the MOS tube V9 is turned off again, the third photosensitive triode in the optical coupler N4 remains in the on state because there is a self-locking mechanism inside the optical coupler N4. This ensures that the system will not be accidentally shut down due to short-term power fluctuations or other reasons after receiving the power-on command. If the system needs to be shut down again, it can be forced to shut down through other control units (such as the shutdown control command unit 8).

[0055] like Figure 3 As shown, the surge suppression control unit 2 includes a resistor R12, a voltage regulator tube V6, a transistor V7, a capacitor C2, a resistor R13, a voltage regulator tube V8 and a MOS tube V9.

[0056] Specifically, the first end of the resistor R12 is connected to the positive electrode of the input bus, and the second end of the resistor R12 is connected to the collector of the transistor V7; the base of the transistor V7 is connected to the negative electrode of the voltage regulator tube V6, and the positive electrode of the voltage regulator tube V6 is grounded; the emitter of the transistor V7 is connected to the first end of the capacitor C2, and the second end of the capacitor C2 is grounded. The first end of the resistor R13 is connected to the emitter of the transistor V7, the second end of the resistor R13 is connected to the first end of the capacitor C3, and the second end of the capacitor C3 is grounded. The negative electrode of the voltage regulator tube V8 is respectively connected to the first end of the capacitor C3, the gate of the MOS tube V9 is connected to the negative electrode of the voltage regulator tube V8, the source of the MOS tube V9 is grounded, and the drain of the MOS tube V9 is connected to the input negative end of the EMI filter unit. The input positive end of the EMI filter unit is connected to the positive electrode of the input bus. Among them, the resistor R12 is used to limit the current flowing into the transistor V7. The voltage regulator tube V6 sets a fixed reference voltage for triggering the transistor V7. Transistor V7 acts as a switch element to control the charging process of capacitor C2. Capacitor C2 and resistor R13 together form an RC delay network for smoothing voltage changes. Resistor R13 and capacitor C2 together form an RC delay network. Capacitor C3 further smoothes voltage changes and provides additional filtering effects. Zener tube V8 is used to protect the gate of MOS tube V9 from excessive voltage. MOS tube V9 acts as the main switch to control the on and off of the input power supply to the EMI filter unit.

[0057] The surge suppression control unit 2 is used to suppress surge current and protect the subsequent circuit. The resistor R12 and the voltage regulator tube V6 are used to detect the input bus voltage and control the conduction state of the transistor V7. When the input voltage exceeds the breakdown voltage of the voltage regulator tube V6, the transistor V7 is turned on, the capacitor C2 is charged, and the voltage of the gate of the MOS tube V9 is gradually increased through the RC network composed of the resistor R13 and the capacitor C3, so that it is slowly turned on, thereby limiting the surge current. The voltage regulator tube V8 is used to protect the gate of the MOS tube V9 from the influence of excessive voltage. The conduction state of the MOS tube V9 determines whether the EMI filter unit and the DC / DC conversion unit receive the input voltage.

[0058] The surge suppression control unit 2 controls the conduction or shutdown of the transistor V7 and the conduction or shutdown of the MOS tube V9, thereby controlling the output of the DC / DC conversion unit. Specifically, when the input bus voltage is within the normal range, the voltage regulator tube V6 will not be turned on, and the transistor V7 is in a cut-off state. Since the transistor V7 is cut off, there is no charging path for capacitors C2 and C3, and the gate voltage of the MOS tube V9 is maintained at a lower level by the voltage regulator tube V8, and the MOS tube V9 is turned on. At this time, the input power is transmitted to the EMI filter unit through the MOS tube V9, and the system works normally. When a surge occurs, that is, when the input bus voltage suddenly rises and exceeds the breakdown voltage of the voltage regulator tube V6, the voltage regulator tube V6 is turned on, so that the base of the transistor V7 obtains a bias current, and the transistor V7 is turned on. After the transistor V7 is turned on, the capacitor C2 begins to charge through the resistor R12 and the transistor V7. During the charging process of the capacitor C2, its voltage gradually rises, and the capacitor C3 is charged through the resistor R13. As the voltage of capacitor C3 rises, the gate voltage of MOS tube V9 also gradually rises, causing MOS tube V9 to gradually shut down. In this way, MOS tube V9 is slowly shut down, limiting the surge current and protecting the subsequent circuit from impact. When the input bus voltage returns to normal, the voltage regulator tube V6 is no longer turned on, and the transistor V7 is turned off. Capacitors C2 and C3 discharge through resistor R13, the gate voltage of MOS tube V9 gradually decreases, MOS tube V9 is turned on again, and the system returns to normal power supply state. This design uses voltage regulator tube V6 and transistor V7 to detect changes in the input bus voltage, and smoothes the voltage changes through an RC delay network (capacitor C2 and resistor R13). When the input voltage surges, MOS tube V9 will slowly shut down, thereby limiting the surge current and protecting the subsequent circuit. This design can not only effectively suppress surge current, but also quickly restore the normal operation of the system after the surge disappears.

[0059] The working principle of the present invention is:

[0060] In the input voltage power-off lock and power-on / off command control circuit described in the present invention, the power-on / off state lock unit 10 is controlled by the power-on command. When the power-on command gives a pulse level, the optocoupler N4 in the power-on / off state lock unit 10 is turned on, and at the same time, the transistor V7 in the surge suppression circuit 2 is turned on, the MOS tube V9 is turned on, and each DC / DC output voltage is normal. When the shutdown command gives a pulse level, the transistor V7 in the surge suppression circuit 2 is turned off, and at the same time, the optocoupler N4 in the power-on / off state lock unit is turned off, the MOS tube V9 is turned off, and the output voltage of each DC / DC is turned off. When the input voltage bus is undervoltage or power-off, the voltage detection voltage of the voltage divider resistor R1 and the voltage divider resistor R2 is lower than the threshold voltage of the in-phase terminal of the op amp, the op amp output is high level, the transistor V5 is turned on, the transistor V7 is turned off, and at the same time, the optocoupler N4 in the power-on / off state lock circuit is turned off, and the output voltage of each DC / DC is turned off. When the input voltage bus voltage is restored, since the optocoupler N4 in the on / off state locking circuit is in the off state, each DC / DC output voltage is in the off state; when there is a power-on command, each DC / DC output voltage works normally.

[0061] The above-described embodiments are merely descriptions of preferred implementations of the present invention and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the scope of protection determined by the claims of the present invention.

Claims

1. An input voltage power-off lock and power on / off command control circuit, characterized in that: The circuit comprises a short circuit protection unit (1), a surge suppression unit (2), an EMI filter unit (3), a DC / DC conversion unit (4), an output filter unit (5) and a control circuit unit (6); The control circuit unit (6) comprises an input bus power-off locking unit (7), a shutdown control command unit (8), a startup control command unit (9) and a startup / shutdown state locking unit (10); The short-circuit protection unit (1) is used to protect a primary power supply; The surge suppression unit (2) is used to suppress surge current generated by the subsequent capacitor and the load; The EMI filter unit (3) is used to suppress the reflected ripple voltage of the DC / DC conversion unit (4) and simultaneously suppress the conducted interference, and input power to the DC / DC conversion unit (4); The DC / DC conversion unit (4) is used to output power supply requirements of different voltage powers of the load; The control circuit unit (6) is used to control the DC / DC conversion unit (4) to start and stop, and when the input bus loses power, controls the DC / DC conversion unit (4) to shut down.

2. The input voltage power-off lock and power on / off command control circuit according to claim 1, characterized in that: The input bus power-off locking unit (7) comprises a resistor R1, a resistor R2, a resistor R3, a voltage regulator tube V1, a resistor R4, a diode V2, an operational amplifier N1, a resistor R7, a resistor R8, a capacitor C1 and a transistor V5; The first end of the resistor R1 is connected to the positive electrode of the input bus, and the second end of the resistor R1 is respectively connected to the first end of the resistor R2 and the reverse end of the operational amplifier N1; the second end of the resistor R2 is grounded; the first end of the resistor R3 is connected to the positive electrode of the input bus, and the second end of the resistor R3 is respectively connected to the negative electrode of the voltage regulator tube V1, the positive end of the operational amplifier N1, and the first end of the resistor R4; the positive electrode of the voltage regulator tube V1 is grounded; the first end of the resistor R4 is also connected to the positive end of the operational amplifier N1, the second end of the resistor R4 is connected to the negative electrode of the diode V2, and the positive electrode of the diode V2 is connected to the output end of the operational amplifier N1; the output end of the operational amplifier N1 is also connected to the first end of the resistor R7, and the second end of the resistor R7 is respectively connected to the first end of the resistor R8, the first end of the capacitor C1, and the base of the transistor V5; the second end of the resistor R8, the second end of the capacitor C1, and the emitter of the transistor V5 are all grounded.

3. The input voltage power-off lock and power on / off command control circuit according to claim 1, characterized in that: The shutdown control command unit (8) comprises an optical coupler N2, a resistor R5 and a diode V3; the optical coupler N2 comprises a first light emitting diode and a first phototransistor; The first end of the resistor R5 is connected to the shutdown command signal, the second end of the resistor R5 is connected to the positive electrode of the diode V3, the negative electrode of the diode V3 is connected to the positive electrode of the first light-emitting diode, and the negative electrode of the first light-emitting diode is grounded; the collector of the first phototransistor is connected to the collector of the transistor V5, and the emitter of the first phototransistor is grounded.

4. The input voltage power-off lock and power on / off command control circuit according to claim 1, characterized in that: The power-on control command unit (9) comprises an optical coupler N3, a resistor R6, a diode V4 and a resistor R9; the optical coupler N3 comprises a second light-emitting diode and a second phototransistor; the first end of the resistor R6 is connected to the power-on command signal, the second end of the resistor R6 is connected to the positive electrode of the diode V4, the negative electrode of the diode V4 is connected to the positive electrode of the first light-emitting diode, and the negative electrode of the second light-emitting diode is grounded; the collector of the second phototransistor is connected to the first end of the resistor R9, the emitter of the second phototransistor is connected to the collector of the transistor V5; the second end of the resistor R9 is connected to the positive electrode of the input bus.

5. The input voltage power-off lock and power on / off command control circuit according to claim 1, characterized in that: The on / off state locking unit (10) comprises an optical coupler N4, a resistor R10 and a resistor R11; the optical coupler N4 comprises a third light emitting diode and a third phototransistor; The first end of the resistor R10 and the first end of the resistor R11 are both connected to the positive electrode of the input bus; the second end of the resistor R10 is connected to the collector of the third phototransistor, and the emitter of the third phototransistor is connected to the collector of the transistor V5; the second end of the resistor R11 is connected to the positive electrode of the third light-emitting diode.

6. The input voltage power-off lock and power on / off command control circuit according to claim 1, characterized in that: The surge suppression control unit (2) comprises a resistor R12, a voltage regulator tube V6, a transistor V7, a capacitor C2, a resistor R13, a voltage regulator tube V8 and a MOS tube V9; The first end of the resistor R12 is connected to the positive electrode of the input bus, and the second end of the resistor R12 is connected to the collector of the transistor V7; the base of the transistor V7 is connected to the negative electrode of the voltage regulator tube V6, and the positive electrode of the voltage regulator tube V6 is grounded; the emitter of the transistor V7 is connected to the first end of the capacitor C2, and the second end of the capacitor C2 is grounded; the first end of the resistor R13 is connected to the emitter of the transistor V7, the second end of the resistor R13 is connected to the first end of the capacitor C3, and the second end of the capacitor C3 is grounded; the negative electrode of the voltage regulator tube V8 is respectively connected to the first end of the capacitor C3, the gate of the MOS tube V9 is connected to the negative electrode of the voltage regulator tube V8, the source of the MOS tube V9 is grounded, and the drain of the MOS tube V9 is connected to the input negative end of the EMI filter unit; the input positive end of the EMI filter unit is connected to the positive electrode of the input bus.

7. The working method of the input voltage power-off lock and power on / off command control circuit is characterized in that: The method is implemented by using the input voltage power-off lock and power on / off command control circuit as claimed in any one of claims 1 to 6, and the method comprises the following steps: S1, controlling the on / off state locking unit (10) through a power-on instruction, when the power-on instruction gives a pulse level, the optical coupler N4 in the on / off state locking unit (10) is turned on, and at the same time, the transistor V7 in the surge suppression circuit (2) is turned on, the MOS tube V9 is turned on, and each DC / DC output voltage is normal; when the power-off instruction gives a pulse level, the transistor V7 in the surge suppression circuit (2) is turned off, and at the same time, the optical coupler N4 in the on / off state locking unit (10) is turned off, the MOS tube V9 is turned off, and each DC / DC output voltage is turned off; S2. When the input voltage bus is undervoltage or powered off, the detection voltage of the voltage divider resistor R1 and the voltage divider resistor R2 is lower than the threshold voltage of the op amp in-phase terminal, the op amp output is high level, the transistor V5 is turned on, the transistor V7 is turned off, and the optocoupler N4 in the switch state locking circuit is turned off, and the DC / DC output voltages of each channel are turned off; S3, when the input voltage bus voltage is restored, since the optocoupler N4 in the on / off state locking circuit (10) is in the off state, each DC / DC output voltage is in the off state; S4. When there is a power-on command, each DC / DC output voltage works normally.

Images