Auxiliary power supply over-voltage and under-voltage detection and judgment circuit for new energy automobile

Abstract

The utility model discloses an auxiliary power supply overvoltage and undervoltage detection and judgment circuit for a new energy automobile. The auxiliary power supply overvoltage and undervoltage detection and judgment circuit comprises an auxiliary power supply port, a detection sampling circuit, a comparison and judgment circuit and an optocoupler isolation circuit. The auxiliary power supply port is connected with the input end of the detection sampling circuit, the input end of the comparison and judgment circuit and the input end of the optical coupler isolation circuit, the output end of the detection sampling circuit is connected with the input end of the comparison and judgment circuit, and the output end of the comparison and judgment circuit is connected with the output end of the optical coupler isolation circuit. The over-voltage and under-voltage detection and judgment function compatible with 12V or 24V auxiliary circuit power supply is achieved, meanwhile, a hardware circuit is used for conducting over-voltage and under-voltage comparison and judgment on auxiliary power supply power supply, corresponding central processing chip computing power resources are saved, and in addition, external input signals and internal control signals are electrically isolated.

Description

Technical Field

[0001] This invention belongs to the field of voltage detection technology and relates to an auxiliary power supply over / under voltage detection and judgment circuit used in new energy vehicles. Background Technology

[0002] With the development of new energy vehicles, the level of electrical automation in these vehicles is becoming increasingly higher. Supporting this increased level of automation are the growing number and increasingly intelligent electronic components on board. For these electronic components, their internal control circuits generally require the 12V or 24V auxiliary power supply from the new energy vehicle. A stable 12V or 24V auxiliary power supply is one of the basic conditions for the normal operation of the low-voltage control circuits within these electronic components. If the 12V or 24V auxiliary power supply deviates from its rated voltage range—that is, if the auxiliary power supply is over-voltage or under-voltage—it may cause the internal control circuits of the electronic components to malfunction, or even prevent them from achieving their pre-designed functions, ultimately resulting in abnormal operation of the electronic components.

[0003] Therefore, most electronic components in new energy vehicles on the market are designed with auxiliary power supply detection circuits. These circuits sample the auxiliary power supply signal through internal detection and sampling circuits, then transmit the sampled signal to the internal central processing chip (CPU). The CPU processes and judges the signal, ultimately determining whether the auxiliary power supply is over- or under-voltage. While this traditional approach, which uses hardware detection and sampling circuits to sample the auxiliary power supply signal and then the CPU processes it, achieves over- or under-voltage detection, it also consumes significant computing resources of the CPU. Summary of the Invention

[0004] To address the problems existing in the background technology, this invention proposes an auxiliary power supply over / under voltage detection and judgment circuit for use in new energy vehicles.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0006] An auxiliary power supply over / under voltage detection and judgment circuit for use in new energy vehicles is characterized by comprising: an auxiliary power supply port, a detection sampling circuit, a comparison and judgment circuit, and an optocoupler isolation circuit.

[0007] The auxiliary power supply port is connected to the input terminal of the detection sampling circuit, the input terminal of the comparison judgment circuit, and the input terminal of the optocoupler isolation circuit. The output terminal of the detection sampling circuit is connected to the input terminal of the comparison judgment circuit, and the output terminal of the comparison judgment circuit is connected to the input terminal of the optocoupler isolation circuit.

[0008] The detection sampling circuit divides the auxiliary power supply through two voltage divider resistors, outputs a sampling signal, and transmits it to the subsequent comparison and judgment circuit.

[0009] The comparison and judgment circuit determines the auxiliary power supply status by comparing the sampled signal with the reference voltage.

[0010] Furthermore, the detection sampling circuit includes resistors R98, R99, R91, R95, R87, R92, R34, R86, capacitors C25 and C27, DIP switch SW1, Pu1 port, Pu2 port, Pd1 port, and Pd2 port.

[0011] The auxiliary power supply port is connected to the output of resistor R98, the input of resistor R91, the input of capacitor C25, the output of resistor R97, the input of resistor R92, and the input of capacitor C27. The input of resistor R98 is connected to the output of resistor R99. The Pu1 port is connected to the input of resistor R99. The output of resistor R91 is connected to the input of resistor R95. The output of capacitor C25 is connected to the input of resistor R87. The outputs of resistors R95 and R87 are connected to ground. The Pu2 port is connected between the output of resistor R91 and the input of resistor R95. The Pu2 port is also connected between the output of capacitor C25 and resistor R87. Between the input terminals, port Pd1 is connected to the input terminal of resistor R97, the output terminal of resistor R92 is connected to the input terminal of resistor R34, the output terminal of capacitor C27 is connected to the input terminal of resistor R86, the output terminals of resistor R34 and R86 are connected to ground, port Pd2 is connected between the output terminal of resistor R92 and the input terminal of resistor R34, port Pd2 is connected between the output terminal of capacitor C27 and the input terminal of resistor R86, pin 1 of DIP switch SW1 is connected to port Pu1, pin 2 of DIP switch SW1 is connected to port Pd1, pin 3 of DIP switch SW1 is connected to port Pd2, and pin 4 of DIP switch SW1 is connected to port Pu2.

[0012] Furthermore, in the detection sampling circuit:

[0013] The detection and sampling circuit supplies power to the auxiliary power supply through two voltage-dividing resistors, and the resulting voltage is used as the detection and sampling signal V. Pu2 and detection sampling signal V Pd2 The detection sampling signal VPu2 is the auxiliary power supply overvoltage comparison signal V. Pu2 Detect sampling signal V Pd2 That is, the auxiliary power supply undervoltage comparison signal V Pd2 By changing the series-parallel structure of the voltage divider resistors through the DIP switch SW1, the overvoltage comparison signal V is maintained. Pu2Undervoltage comparison signal V Pd2 Relatively unchanged.

[0014] Furthermore, under the auxiliary power supply of 24V, the two channels inside the DIP switch SW1 are set to the open circuit state, that is, the Pu1 port and the Pu2 port are not shorted, and the Pd1 port and the Pd2 port are not shorted, which is used to divide the voltage to obtain the overvoltage comparison signal V. Pu2 The voltage divider resistors R98 and R99 are not connected in parallel with the voltage divider resistor R91, therefore the overvoltage comparison signal is not connected in parallel under these conditions.

[0015] Undervoltage comparison signal .

[0016] With the auxiliary power supply at 12V, the two channels inside the DIP switch SW1 are set to the on state, that is, the Pu1 port is shorted to the Pu2 port, and the Pd1 port is shorted to the Pd2 port. The voltage divider resistors R98 and R99 are connected in parallel with the voltage divider resistor R91. Therefore, in this state...

[0017] Undervoltage comparison signal .

[0018] Furthermore, the comparison and judgment circuit includes resistors R81, R19, R20, R32, R33, R93, R94, a reference voltage port, a voltage reference source U6, a first comparator, a second comparator, a switching diode D1, and a switching diode D19, wherein the reference voltage port outputs a reference voltage Vref;

[0019] The auxiliary power supply port is connected to the input terminal of resistor R81. The output terminal of resistor R81 is connected to pin 1 and pin 2 of voltage reference source U6, and the input terminal of resistor R19. The reference voltage port is connected to the input terminal of resistor R19. Pin 3 of voltage reference source U6 and the output terminal of resistor R19 are connected to ground. The Pd2 port is connected to the input terminal of resistor R20. The output terminal of resistor R20 is connected to the non-inverting input terminal of the first comparator and the input terminal of resistor R93. The output terminal of resistor R93 is connected to the switching diode D19. The positive terminal is connected to the reference voltage port and the input terminal of resistor R32. The output terminal of resistor R32 is connected to the inverting input terminal of the first comparator, the non-inverting input terminal of the second comparator, and the input terminal of resistor R94. The Pu2 port is connected to the input terminal of resistor R33. The output terminal of resistor R33 is connected to the inverting input terminal of the second comparator. The output terminal of resistor R94 is connected to the positive terminal of switching diode D1. The output terminal of the first comparator is connected to the output terminal of the second comparator, the negative terminal of switching diode D19, and the negative terminal of switching diode D1.

[0020] Furthermore, in the comparison and judgment circuit:

[0021] The first and second comparators form a dual-channel comparator. The comparison and judgment circuit processes the auxiliary power supply overvoltage comparison signal, the auxiliary power supply undervoltage comparison signal, and the auxiliary power supply overvoltage / undervoltage fault signal to obtain the overvoltage / undervoltage fault signal.

[0022] Furthermore, the optocoupler isolation circuit includes resistors R88, R79, and R27, capacitors C28 and C29, an isolation optocoupler U3, and a control signal port;

[0023] The auxiliary power supply port is connected to the input terminal of resistor R88. The output terminal of resistor R88 is connected to pin 1 of the isolation optocoupler U3. Pin 2 of the isolation optocoupler U3 is connected to the output terminal of the second comparator. Resistor R79 is connected in parallel across pins 1 and 2 of the isolation optocoupler U3. Capacitor C28 is connected in parallel across resistor R79. Pin 4 of the isolation optocoupler U3 is connected to the +5V power supply. Pin 3 of the isolation optocoupler U3 is connected to the input terminal and control signal port of capacitor C29. The output terminal of capacitor C29 is connected to ground. Resistor R27 is connected in parallel across capacitor C29.

[0024] Furthermore, in the optocoupler isolation circuit;

[0025] The primary side of the isolation optocoupler U3 receives the auxiliary power supply over / under voltage fault signal output by the comparison and judgment circuit, and the control signal port outputs the auxiliary power supply over / under voltage control signal. The secondary side of the isolation optocoupler U3 receives the corresponding auxiliary power supply over / under voltage control signal.

[0026] The primary-side signal is isolated by an optocoupler to indirectly control the conduction or cutoff of the secondary-side phototransistor. The primary and secondary sides of the optocoupler rely on optical signals for signal transmission.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] This invention proposes an auxiliary power supply over / under voltage detection and judgment circuit for use in new energy vehicles. Through three sub-circuits—a detection sampling circuit, a comparison and judgment circuit, and an optocoupler isolation circuit—it achieves over / under voltage detection and judgment functions compatible with both 12V and 24V auxiliary power supplies. At the same time, it uses hardware circuitry to perform over / under voltage comparison and judgment of the auxiliary power supply, saving corresponding central processing chip computing resources. In addition, it provides electrical isolation between external input signals and internal control signals. Attached Figure Description

[0029] Figure 1 This is the overall circuit diagram of the auxiliary power supply over / under voltage detection and judgment circuit of the present invention;

[0030] Figure 2 This is the detection and sampling circuit of the present invention;

[0031] Figure 3 This is the comparison and judgment circuit of the present invention;

[0032] Figure 4 This is the auxiliary power supply overvoltage comparison logic diagram of the present invention;

[0033] Figure 5 This is the auxiliary power supply undervoltage comparison logic diagram of the present invention;

[0034] Figure 6 This invention relates to an optocoupler isolation circuit. Detailed Implementation

[0035] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0036] like Figures 1-6 As shown, the technical solution adopted in this invention is as follows:

[0037] like Figure 1 As shown, an auxiliary power supply over / under voltage detection and judgment circuit used in new energy vehicles includes: an auxiliary power supply port, a detection sampling circuit, a comparison and judgment circuit, and an optocoupler isolation circuit.

[0038] The auxiliary power supply port is connected to the input of the detection sampling circuit, the input of the comparison and judgment circuit, and the input of the optocoupler isolation circuit.

[0039] The output of the detection sampling circuit is connected to the input of the comparison and judgment circuit.

[0040] The output of the comparison and judgment circuit is connected to the input of the optocoupler isolation circuit.

[0041] The detection sampling circuit divides the auxiliary power supply through two voltage divider resistors, outputs a sampling signal, and transmits it to the subsequent comparison and judgment circuit.

[0042] The comparison and judgment circuit compares the sampled signal with the reference voltage to determine the auxiliary power supply status, so as to transmit the information to the subsequent optocoupler isolation circuit.

[0043] Optical isolation circuits achieve electrical isolation between external input signals and internal control signals through optical isolation, so that the central processing chip can perform relevant fault protection operations.

[0044] like Figure 2As shown, the detection sampling circuit includes resistors R98, R99, R91, R95, R87, R92, R34, R86, capacitors C25 and C27, DIP switch SW1, Pu1 port, Pu2 port, Pd1 port, and Pd2 port.

[0045] The auxiliary power supply port is connected to the output of resistor R98, the input of resistor R91, the input of capacitor C25, the output of resistor R97, the input of resistor R92, and the input of capacitor C27. The input of resistor R98 is connected to the output of resistor R99. The Pu1 port is connected to the input of resistor R99. The output of resistor R91 is connected to the input of resistor R95. The output of capacitor C25 is connected to the input of resistor R87. The outputs of resistors R95 and R87 are connected to ground. The Pu2 port is connected between the output of resistor R91 and the input of resistor R95. The Pu2 port is also connected between the output of capacitor C25 and resistor R87. Between the input terminals, port Pd1 is connected to the input terminal of resistor R97, the output terminal of resistor R92 is connected to the input terminal of resistor R34, the output terminal of capacitor C27 is connected to the input terminal of resistor R86, the output terminals of resistor R34 and R86 are connected to ground, port Pd2 is connected between the output terminal of resistor R92 and the input terminal of resistor R34, port Pd2 is connected between the output terminal of capacitor C27 and the input terminal of resistor R86, pin 1 of DIP switch SW1 is connected to port Pu1, pin 2 of DIP switch SW1 is connected to port Pd1, pin 3 of DIP switch SW1 is connected to port Pd2, and pin 4 of DIP switch SW1 is connected to port Pu2.

[0046] Resistors R34, R86, R87, R91, R92, R95, R97, R98, and R99 all function as voltage dividers. However, in this detection and sampling circuit, resistors R87, R91, R95, R98, and R99 are only used to divide the auxiliary power supply V1, which then serves as the overvoltage comparison signal V for the auxiliary power supply. Pu2 The signal is transmitted to the inverting input of the subsequent comparison and judgment circuit.

[0047] While the remaining voltage divider resistors R34, R86, R92, and R97 are also used to divide the voltage of the auxiliary power supply V1, their resistance values ​​are different from those used to obtain the overvoltage comparison signal V for the auxiliary power supply port. Pu2The resistors R87, R91, R95, R98, and R99 have different resistance values. Therefore, the signal obtained after dividing the auxiliary power supply V1 using voltage divider resistors R34, R86, R92, and R97 is the auxiliary power supply undervoltage comparison signal V. Pd2 Auxiliary power supply undervoltage comparison signal V Pd2 In this circuit, it is output to the non-inverting input of the subsequent comparison and judgment circuit.

[0048] Furthermore, auxiliary power supplies in new energy vehicles not only have a 24V supply voltage level but also a 12V supply voltage. Therefore, to improve the overall compatibility of this auxiliary power over / under voltage detection and judgment circuit, a DIP switch SW1 is used in the detection sampling circuit of this invention to switch the series-parallel connection of the voltage divider resistors within the detection sampling circuit. This changes the structure of the detection sampling circuit, enabling the detection sampling circuit of this invention to evaluate the overvoltage comparison signal V obtained from the voltage divider resistors in both 12V and 24V auxiliary power supply systems. Pu2 Or undervoltage comparison signal V Pd2 No impact.

[0049] With the auxiliary power supply at 24V, the two channels inside the DIP switch SW1 are set to the open circuit state, meaning that the Pu1 port and the Pu2 port are not shorted, and the Pd1 port and the Pd2 port are not shorted. This means that the signal is used for voltage division to obtain the overvoltage comparison signal V. Pu2 The voltage divider resistors R98 and R99 are not connected in parallel with the voltage divider resistor R91, therefore the overvoltage comparison signal is not connected in parallel under these conditions.

[0050] Undervoltage comparison signal .

[0051] With the auxiliary power supply at 12V, the two channels inside the DIP switch SW1 are set to the on state, that is, the Pu1 port is shorted to the Pu2 port, and the Pd1 port is shorted to the Pd2 port. The voltage divider resistors R98 and R99 are connected in parallel with the voltage divider resistor R91. Therefore, in this state...

[0052] Undervoltage comparison signal .

[0053] The above formula can be used to determine V. V1 The resistance values ​​of each voltage divider resistor R34, R86, R87, R91, R92, R95, R97, R98, and R99 are preset to maintain the overvoltage comparison signal V after the series-parallel structure of the voltage divider resistors is changed by SW1. Pu2 Comparison signal V with undervoltage Pd2The goal remains relatively unchanged, and ultimately, this will achieve compatibility between 12V auxiliary power supply and 24V auxiliary power supply detection and sampling functions.

[0054] like Figure 3 As shown, the comparison and judgment circuit includes resistors R81, R19, R20, R32, R33, R93, R94, a reference voltage port, a voltage reference source U6, a first comparator, a second comparator, a switching diode D1, and a switching diode D19, wherein the reference voltage port outputs a reference voltage Vref.

[0055] The auxiliary power supply port is connected to the input terminal of resistor R81. The output terminal of resistor R81 is connected to pin 1 and pin 2 of voltage reference source U6, and the input terminal of resistor R19. The reference voltage port is connected to the input terminal of resistor R19. Pin 3 of voltage reference source U6 and the output terminal of resistor R19 are connected to ground. The Pd2 port is connected to the input terminal of resistor R20. The output terminal of resistor R20 is connected to the non-inverting input terminal of the first comparator and the input terminal of resistor R93. The output terminal of resistor R93 is connected to the switching diode D19. The positive terminal is connected to the reference voltage port and the input terminal of resistor R32. The output terminal of resistor R32 is connected to the inverting input terminal of the first comparator, the non-inverting input terminal of the second comparator, and the input terminal of resistor R94. The Pu2 port is connected to the input terminal of resistor R33. The output terminal of resistor R33 is connected to the inverting input terminal of the second comparator. The output terminal of resistor R94 is connected to the positive terminal of switching diode D1. The output terminal of the first comparator is connected to the output terminal of the second comparator, the negative terminal of switching diode D19, and the negative terminal of switching diode D1.

[0056] The over / under voltage detection and judgment circuit of this invention is compatible with both 12V and 24V auxiliary power supplies. Since the auxiliary power supply in a new energy vehicle is not a constant value and fluctuates between 12V and 24V as the vehicle operates, a voltage reference source U6 is used in this comparison and judgment circuit to obtain the reference voltage Vref. This avoids the instability of the reference voltage Vref obtained solely through voltage divider resistors R81 and R19. After the auxiliary power supply is input to this comparison and judgment circuit, the reference voltage Vref is output through voltage divider resistors R81 and R19. In addition to being output to comparator U2, the reference voltage Vref is also transmitted to pin 2 of the voltage reference source U6 for voltage regulation. When the reference voltage Vref is lower than the reference voltage within the voltage reference source U6, the anode and cathode of the voltage reference source U6 are in an off state, meaning pins 1 and 3 are not conducting. In this state, voltage divider resistor R19 participates in voltage division, thereby increasing the reference voltage Vref. Conversely, when the reference voltage Vref is higher than the reference voltage within the voltage reference source U6, the anode and cathode of the voltage reference source U6 are in a conducting state, that is, pin 1 and pin 3 of the voltage reference source are connected. In this state, the voltage divider resistor R19 does not participate in the voltage division, thereby causing the reference voltage Vref to decrease. Based on this principle, the reference voltage Vref can be kept stable even when the auxiliary power supply voltage fluctuates.

[0057] In this comparison and judgment circuit, the first comparator and the second comparator form a dual-channel comparator. Channel one consists of the non-inverting input, the inverting input, and the output of the first comparator, and is used to assist in overvoltage comparison and judgment of the power supply. Channel two consists of the non-inverting input, the inverting input, and the output of the second comparator, and is used to assist in undervoltage comparison and judgment of the power supply. When the inverting input of the second comparator receives the overvoltage comparison signal V from the upper-level detection and sampling circuit... Pu2 Then, it will be compared with the reference voltage Vref received at the non-inverting input of the second comparator.

[0058] like Figure 4 As shown, when the overvoltage comparison signal V Pu2 When the voltage exceeds the reference voltage Vref, the output of the second comparator will switch from a high-impedance state to a low-impedance state, indicating an auxiliary power supply overvoltage fault signal. Conversely, when the voltage is below the reference voltage Vref, the output of the second comparator will remain in a high-impedance state.

[0059] Furthermore, to avoid repeated output of auxiliary power supply overvoltage fault signals when the auxiliary power supply fluctuates around the overvoltage point, this comparison circuit achieves a hysteresis comparison effect through switching diode D19, resistor R32, and resistor R94. When the output of the second comparator flips to a low-impedance state, under the action of voltage divider resistors R32 and R94, the larger flip point of the second comparator will change from the reference voltage Vref to... This allows for the hysteresis effect of overvoltage comparison in the auxiliary power supply. Furthermore, due to the unidirectional conductivity of the switching diode, when the output of the second comparator remains in a high configuration, resistors R32 and R34 do not perform a voltage divider function. At this time, the flip-down voltage point of the second comparator remains unchanged, still at the reference voltage Vref.

[0060] like Figure 5 As shown, similarly, when the non-inverting input of the first comparator receives the undervoltage comparison signal V output by the upper-level detection and sampling circuit... Pd2 Then, it will be compared with the reference voltage Vref received at the inverting input of the first comparator. If the undervoltage comparison signal V... Pd2 When the voltage is less than the reference voltage Vref, the output of the first comparator will flip from a high-impedance state to a low-impedance state, indicating an undervoltage fault signal in the auxiliary power supply. Otherwise, it will maintain a high-impedance output. The hysteresis comparison effect in the undervoltage comparison process is achieved by resistors R93 and R20. When the output of the first comparator flips to a low-impedance state, under the action of the voltage divider resistors R93 and R20, the undervoltage comparison signal input to the non-inverting input of the first comparator will change from a high-impedance state to a low-impedance state. Pd2 Become At this time, the flip-up voltage point of the corresponding first comparator changes from the reference voltage Vref to... This achieves the comparison effect of undervoltage hysteresis in the auxiliary power supply. Similarly, due to the unidirectional conductivity of the switching diode, when the output of the first comparator remains in a high-impedance state, resistors R20 and R93 do not have a voltage division effect; at this time, the undervoltage comparison signal V... Pd2 No change.

[0061] In summary, the comparison and judgment circuit can process the auxiliary power supply overvoltage comparison signal, the auxiliary power supply undervoltage comparison signal, and the auxiliary power supply overvoltage / undervoltage fault signal, thereby realizing the auxiliary power supply overvoltage / undervoltage judgment function and avoiding the occupation of the central processing chip's computing resources.

[0062] like Figure 6 As shown, the optocoupler isolation circuit includes resistors R88, R79, and R27, capacitors C28 and C29, an isolation optocoupler U3, and a control signal port.

[0063] The auxiliary power supply port is connected to the input terminal of resistor R88. The output terminal of resistor R88 is connected to pin 1 of the isolation optocoupler U3. Pin 2 of the isolation optocoupler U3 is connected to the output terminal of the second comparator. Resistor R79 is connected in parallel across pins 1 and 2 of the isolation optocoupler U3. Capacitor C28 is connected in parallel across resistor R79. Pin 4 of the isolation optocoupler U3 is connected to the +5V power supply. Pin 3 of the isolation optocoupler U3 is connected to the input terminal and control signal port of capacitor C29. The output terminal of capacitor C29 is connected to ground. Resistor R27 is connected in parallel across capacitor C29.

[0064] The auxiliary power supply port is connected to the input terminal of capacitor C87, and the output terminal of capacitor C87 is connected to ground. This can stabilize the voltage and filter out noise.

[0065] Connect a test point TP35 between the control signal port and the input terminal of capacitor C29. Test point TP35 can monitor the signal status related to over- and under-voltage faults in the auxiliary power supply, and further determine whether the auxiliary power supply is working properly.

[0066] After a 12V or 24V auxiliary power supply is input to this optocoupler isolation circuit, it can be connected to pin 1 of optocoupler U3 through current-limiting resistor R88. If pin 2 of optocoupler U3 receives an auxiliary power supply over / under voltage fault signal output from the upper-level comparison circuit, i.e., pin 2 of optocoupler U3 flips to a low-impedance state, the primary-side LED of optocoupler U3 conducts, emitting a light signal of a certain wavelength and intensity. This light signal is transmitted internally within optocoupler U3 using optical fiber as the medium. When it reaches the secondary-side phototransistor of optocoupler U3, it drives the phototransistor to conduct. Since pin 4 of optocoupler U3 is connected to the +5V power supply, and pin 3 is connected to the auxiliary power supply over / under voltage control signal, the collector and emitter of the secondary-side phototransistor of optocoupler U3 are respectively connected to +5V and the auxiliary power supply over / under voltage control signal. Therefore, once the phototransistor on the secondary side of the isolation optocoupler U3 is turned on, the auxiliary power supply over / under voltage control signal can be pulled up to +5V. After the central processing chip detects this pulled-up 5V auxiliary power supply over / under voltage control signal, it can execute the corresponding auxiliary power supply over / under voltage protection operation.

[0067] Similarly, if pin 2 of the isolation optocoupler U3 does not receive the auxiliary power supply over / under voltage fault signal output by the upper-level comparison and judgment circuit, that is, pin 2 of the isolation optocoupler U3 remains in a high impedance state, then the light-emitting diode on the primary side of the isolation optocoupler will not conduct, and the phototransistor on the secondary side of the isolation optocoupler U3 will also be in the off state. At this time, the auxiliary power supply over / under voltage control signal is pulled down to GND through resistor R27 to avoid interference that could cause the central processing chip to erroneously execute the corresponding auxiliary power supply over / under voltage protection operation.

[0068] In summary, the auxiliary power supply over / under voltage fault signal output by the comparison judgment circuit is only transmitted to the primary side of the isolation optocoupler U3, while the corresponding auxiliary power supply over / under voltage control signal is located on the secondary side of the isolation optocoupler U3. The primary side signal is indirectly controlled to turn on or off the secondary side phototransistor after being isolated by the optocoupler. The primary and secondary sides of the optocoupler rely on optical signals for signal transmission, thereby achieving electrical isolation between external input signals and internal control signals.

[0069] The external input signal is the over / under voltage fault signal output by the comparison and judgment circuit, and the internal control signal is the over / under voltage control signal output by the control signal port.

[0070] In summary, this invention achieves over / under voltage detection and judgment functions compatible with both 12V and 24V auxiliary circuit power supplies. At the same time, it uses hardware circuits to compare and judge the over / under voltage of the auxiliary power supply, saving corresponding central processing chip computing resources. In addition, it provides electrical isolation between external input signals and internal control signals.

[0071] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An auxiliary power supply over / under voltage detection and judgment circuit used in new energy vehicles, characterized in that, It includes: auxiliary power supply port, detection sampling circuit, comparison and judgment circuit, and optocoupler isolation circuit; The auxiliary power supply port is connected to the input terminal of the detection sampling circuit, the input terminal of the comparison judgment circuit, and the input terminal of the optocoupler isolation circuit. The output terminal of the detection sampling circuit is connected to the input terminal of the comparison judgment circuit, and the output terminal of the comparison judgment circuit is connected to the input terminal of the optocoupler isolation circuit. The detection sampling circuit divides the auxiliary power supply through two voltage divider resistors, outputs a sampling signal, and transmits it to the subsequent comparison and judgment circuit. The comparison and judgment circuit determines the auxiliary power supply status by comparing the sampled signal with the reference voltage.

2. The auxiliary power supply over / under voltage detection and judgment circuit for use in new energy vehicles according to claim 1, characterized in that, The detection sampling circuit includes resistors R98, R99, R91, R95, R87, R97, R92, R34, R86, capacitors C25 and C27, DIP switch SW1, Pu1 port, Pu2 port, Pd1 port, and Pd2 port. The auxiliary power supply port is connected to the output of resistor R98, the input of resistor R91, the input of capacitor C25, the output of resistor R97, the input of resistor R92, and the input of capacitor C27. The input of resistor R98 is connected to the output of resistor R99. The Pu1 port is connected to the input of resistor R99. The output of resistor R91 is connected to the input of resistor R95. The output of capacitor C25 is connected to the input of resistor R87. The outputs of resistors R95 and R87 are connected to ground. The Pu2 port is connected between the output of resistor R91 and the input of resistor R95. The Pu2 port is also connected between the output of capacitor C25 and resistor R87. Between the input terminals, port Pd1 is connected to the input terminal of resistor R97, the output terminal of resistor R92 is connected to the input terminal of resistor R34, the output terminal of capacitor C27 is connected to the input terminal of resistor R86, the output terminals of resistor R34 and R86 are connected to ground, port Pd2 is connected between the output terminal of resistor R92 and the input terminal of resistor R34, port Pd2 is connected between the output terminal of capacitor C27 and the input terminal of resistor R86, pin 1 of DIP switch SW1 is connected to port Pu1, pin 2 of DIP switch SW1 is connected to port Pd1, pin 3 of DIP switch SW1 is connected to port Pd2, and pin 4 of DIP switch SW1 is connected to port Pu2.

3. The auxiliary power supply over / under voltage detection and judgment circuit for use in new energy vehicles according to claim 2, characterized in that, In the detection and sampling circuit: The detection and sampling circuit supplies power to the auxiliary power supply through two voltage-dividing resistors, and the resulting voltage is used as the detection and sampling signal V. Pu2 and detection sampling signal V Pd2 The detection sampling signal VPu2 is the auxiliary power supply overvoltage comparison signal V. Pu2 Detect sampling signal V Pd2 That is, the auxiliary power supply undervoltage comparison signal V Pd2 ; By changing the series-parallel connection structure of the voltage divider resistors through the DIP switch SW1, the overvoltage comparison signal V is maintained. Pu2 Undervoltage comparison signal V Pd2 Relatively unchanged.

4. The auxiliary power supply over / under voltage detection and judgment circuit for use in new energy vehicles according to claim 1, characterized in that, The comparison and judgment circuit includes resistors R81, R19, R20, R32, R33, R93, R94, a reference voltage port, a voltage reference source U6, a first comparator, a second comparator, a switching diode D1, and a switching diode D19, wherein the reference voltage port outputs a reference voltage Vref; The auxiliary power supply port is connected to the input terminal of resistor R81. The output terminal of resistor R81 is connected to pin 1 and pin 2 of voltage reference source U6, and the input terminal of resistor R19. The reference voltage port is connected to the input terminal of resistor R19. Pin 3 of voltage reference source U6 and the output terminal of resistor R19 are connected to ground. The Pd2 port is connected to the input terminal of resistor R20. The output terminal of resistor R20 is connected to the non-inverting input terminal of the first comparator and the input terminal of resistor R93. The output terminal of resistor R93 is connected to the switching diode D19. The positive terminal is connected to the reference voltage port and the input terminal of resistor R32. The output terminal of resistor R32 is connected to the inverting input terminal of the first comparator, the non-inverting input terminal of the second comparator, and the input terminal of resistor R94. The Pu2 port is connected to the input terminal of resistor R33. The output terminal of resistor R33 is connected to the inverting input terminal of the second comparator. The output terminal of resistor R94 is connected to the positive terminal of switching diode D1. The output terminal of the first comparator is connected to the output terminal of the second comparator, the negative terminal of switching diode D19, and the negative terminal of switching diode D1.

5. The auxiliary power supply over / under voltage detection and judgment circuit for use in new energy vehicles according to claim 4, characterized in that, In the comparison and judgment circuit: The first and second comparators form a dual-channel comparator. The comparison and judgment circuit processes the auxiliary power supply overvoltage comparison signal, the auxiliary power supply undervoltage comparison signal, and the auxiliary power supply overvoltage / undervoltage fault signal to obtain the overvoltage / undervoltage fault signal.

6. The auxiliary power supply over / under voltage detection and judgment circuit for use in new energy vehicles according to any one of claims 1 or 4, characterized in that, The optocoupler isolation circuit includes resistors R88, R79, and R27, capacitors C28 and C29, an isolation optocoupler U3, and a control signal port; The auxiliary power supply port is connected to the input terminal of resistor R88. The output terminal of resistor R88 is connected to pin 1 of the isolation optocoupler U3. Pin 2 of the isolation optocoupler U3 is connected to the output terminal of the second comparator. Resistor R79 is connected in parallel across pins 1 and 2 of the isolation optocoupler U3. Capacitor C28 is connected in parallel across resistor R79. Pin 4 of the isolation optocoupler U3 is connected to the +5V power supply. Pin 3 of the isolation optocoupler U3 is connected to the input terminal and control signal port of capacitor C29. The output terminal of capacitor C29 is connected to ground. Resistor R27 is connected in parallel across capacitor C29.

7. The auxiliary power supply over / under voltage detection and judgment circuit for use in new energy vehicles according to claim 6, characterized in that, In the optocoupler isolation circuit: The primary side of the isolation optocoupler U3 receives the auxiliary power supply over / under voltage fault signal output by the comparison and judgment circuit, and the control signal port outputs the auxiliary power supply over / under voltage control signal. The secondary side of the isolation optocoupler U3 receives the corresponding auxiliary power supply over / under voltage control signal. The primary-side signal is isolated by an optocoupler to indirectly control the conduction or cutoff of the secondary-side phototransistor. The primary and secondary sides of the optocoupler rely on optical signals for signal transmission.

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