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

Abstract

The invention 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] The invention belongs to the technical field of voltage detection, and relates to an auxiliary power supply over-voltage and under-voltage detection and judgment circuit used in new energy vehicles. Background Art

[0002] With the development of new energy vehicles, the degree of electrical automation of new energy vehicles is becoming higher and higher, and the improvement of the degree of electrical automation of the whole vehicle is supported by the increasing number of various electronic components on the vehicle with increasingly intelligent functions. For electronic components on the market, their internal control circuits basically need to use the 12V or 24V auxiliary power supply on new energy vehicles to power the control circuits. Stable 12V or 24V auxiliary power supply is one of the basic conditions for the normal operation of the low-voltage control circuit inside the electronic components. If the 12V or 24V auxiliary power supply on the new energy vehicle deviates from the rated voltage range, that is, the auxiliary power supply is overvoltage or undervoltage, it is possible that the internal control circuit of the electronic component may work abnormally, or even fail to realize the pre-designed functions, and finally cause the electronic component to work abnormally.

[0003] Therefore, the vast majority of new energy vehicle electronic components on the market are designed with auxiliary power supply detection circuits, which sample the auxiliary power supply through the internal detection sampling circuit, and then transmit the detection sampling signal to the internal central processing chip, which performs signal judgment and processing, and finally realizes the auxiliary power supply over-voltage and under-voltage judgment function. This traditional solution samples the auxiliary power supply signal through the hardware detection sampling circuit, and then the central processing chip judges and processes the detection sampling signal. Although it realizes the auxiliary power supply over-voltage and under-voltage detection and judgment function, it also occupies the computing power resources of the central processing chip to a certain extent. Summary of the invention

[0004] In order to solve the problems existing in the background technology, the present invention proposes an auxiliary power supply over-voltage and under-voltage detection and judgment circuit for new energy vehicles.

[0005] In order to achieve the above object, the technical solution adopted by the present invention is as follows: An auxiliary power supply over-voltage and under-voltage detection and judgment circuit for new energy vehicles, characterized in that it includes: an auxiliary power supply port, a detection sampling circuit, a comparison judgment circuit, and an optical coupling isolation circuit; The auxiliary power supply port is connected to the input end of the detection sampling circuit, the input end of the comparison judgment circuit, and the input end of the optical coupling isolation circuit; the output end of the detection sampling circuit is connected to the input end of the comparison judgment circuit; and the output end of the comparison judgment circuit is connected to the input end of the optical coupling isolation circuit; The detection sampling circuit divides the auxiliary power supply voltage through two voltage-dividing resistors, outputs a sampling signal, and transmits it to the subsequent comparison and judgment circuit; The comparison and judgment circuit compares the sampling signal with the reference voltage to judge the power supply state of the auxiliary power supply.

[0006] Further, the detection sampling circuit includes a resistor R98, a resistor R99, a resistor R91, a resistor R95, a resistor R87, a resistor R97, a resistor R92, a resistor R34, a resistor R86, a capacitor C25, a capacitor C27, a dip switch SW1, a Pu1 port, a Pu2 port, a Pd1 port, and a Pd2 port; The auxiliary power supply port is connected to the output end of resistor R98, the input end of resistor R91, the input end of capacitor C25, the output end of resistor R97, the input end of resistor R92, and the input end of capacitor C27. The input end of resistor R98 is connected to the output end of resistor R99. The Pu1 port is connected to the input end of resistor R99. The output end of resistor R91 is connected to the input end of resistor R95. The output end of capacitor C25 is connected to the input end of resistor R87. The output end of resistor R95 and the output end of resistor R87 are connected to ground. The Pu2 port is connected between the output end of resistor R91 and the input end of resistor R95. The Pu2 port is connected between the output end of capacitor C25 and resistor R87. The Pd1 port is connected to the input end of resistor R97, the output end of resistor R92 is connected to the input end of resistor R34, the output end of capacitor C27 is connected to the input end of resistor R86, the output end of resistor R34 and the output end of resistor R86 are connected to ground, the Pd2 port is connected between the output end of resistor R92 and the input end of resistor R34, the Pd2 port is connected between the output end of capacitor C27 and the input end of resistor R86, pin 1 of dip switch SW1 is connected to Pu1 port, pin 2 of dip switch SW1 is connected to Pd1 port, pin 3 of dip switch SW1 is connected to Pd2 port, and pin 4 of dip switch SW1 is connected to Pu2 port.

[0007] Furthermore, in the detection sampling circuit: The detection sampling circuit divides the auxiliary power supply voltage through two voltage-dividing resistors and uses them as detection sampling signals V Pu2 and detect the sampling signal V Pd2 , detect the sampling signal V Pu2, that is, the auxiliary power supply overvoltage comparison signal V Pu2 , detect the sampling signal V Pd2 That is, the auxiliary power supply undervoltage comparison signal V Pd2 , and maintain the overvoltage comparison signal V by changing the series-parallel structure of the voltage divider resistors through the DIP switch SW1 Pu2 , undervoltage comparison signal V Pd2 Relatively unchanged.

[0008] Furthermore, when the auxiliary power supply is 24V, the two channels inside the DIP switch SW1 are set to an open circuit state, that is, the Pu1 port and the Pu2 port are not short-circuited, and the Pd1 port and the Pd2 port are not short-circuited, which are 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 to the voltage divider resistor R91, so the overvoltage comparison signal , undervoltage comparison signal .

[0009] When the auxiliary power supply is 12V, the two channels inside the DIP switch SW1 are set to the on state, that is, the Pu1 port is short-circuited with the Pu2 port, the Pd1 port is short-circuited with the Pd2 port segment, and the voltage divider resistors R98 and R99 are connected in parallel to the voltage divider resistor R91. Therefore, in this state , undervoltage comparison signal .

[0010] Further, the comparison judgment circuit includes a resistor R81, a resistor R19, a resistor R20, a resistor R32, a resistor R33, a resistor R93, a resistor 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 end of the resistor R81, the output end of the resistor R81 is connected to the voltage reference source U6 pin 1, the voltage reference source U6 pin 2, and the input end of the resistor R19, the reference voltage port is connected to the input end of the resistor R19, the voltage reference source U6 pin 3, the output end of the resistor R19 is connected to the ground, the Pd2 port is connected to the input end of the resistor R20, the output end of the resistor R20 is connected to the in-phase input end of the first comparator and the input end of the resistor R93, and the output end of the resistor R93 is connected to the switching diode D19 The positive electrode is connected, the reference voltage port is connected to the input end of resistor R32, the output end of resistor R32 is connected to the inverting input end of the first comparator, the non-inverting input end of the second comparator, and the input end of resistor R94, the Pu2 port is connected to the input end of resistor R33, the output end of resistor R33 is connected to the inverting input end of the second comparator, the output end of resistor R94 is connected to the positive electrode of the switching diode D1, the output end of the first comparator is connected to the output end of the second comparator, the cathode of the switching diode D19, and the cathode of the switching diode D1.

[0011] Furthermore, in the comparison and judgment circuit: The first comparator and the second comparator form a dual-channel comparator. The comparison judgment circuit processes the auxiliary power supply overvoltage comparison signal, the auxiliary power supply undervoltage comparison signal to the auxiliary power supply overvoltage or undervoltage fault signal to obtain an overvoltage or undervoltage fault signal.

[0012] Further, the optocoupler isolation circuit includes a resistor R88, a resistor R79, a resistor R27, a capacitor C28, a capacitor C29, an isolation optocoupler U3, and a control signal port; The auxiliary power supply port is connected to the input end of resistor R88, the output end 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 end of the second comparator, resistor R79 is connected in parallel on both sides of pin 1 and pin 2 of the isolation optocoupler U3, capacitor C28 is connected in parallel on both sides of 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 end and control signal port of capacitor C29, the output end of capacitor C29 is connected to ground, and resistor R27 is connected in parallel across capacitor C29.

[0013] Further, in the optical coupling isolation circuit; The primary side of the isolation optocoupler U3 receives the auxiliary power supply over-voltage or under-voltage fault signal output by the comparison judgment circuit, the control signal port outputs the auxiliary power supply over-voltage or under-voltage control signal, and the secondary side of the isolation optocoupler U3 receives the corresponding auxiliary power supply over-voltage or under-voltage control signal; The primary side signal is isolated by an optocoupler to indirectly control the on or off of the secondary side phototransistor. The primary and secondary sides of the optocoupler are transmitted by optical signals.

[0014] Compared with the prior art, the present invention has the following beneficial effects: The present invention proposes an auxiliary power supply over-voltage and under-voltage detection and judgment circuit for new energy vehicles. The circuit realizes the over-voltage and under-voltage detection and judgment functions compatible with both 12V and 24V auxiliary power supplies through the detection sampling circuit, the comparison judgment circuit, and the optical coupling isolation circuit. At the same time, the hardware circuit is used to compare and judge the over-voltage and under-voltage of the auxiliary power supply, which saves the corresponding central processing chip computing power resources. In addition, the external input signal and the internal control signal are electrically isolated. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is the overall circuit diagram of the auxiliary power supply over-voltage and under-voltage detection and judgment circuit of the present invention; Figure 2 The detection sampling circuit of the present invention; Figure 3 The comparison and judgment circuit of the present invention; Figure 4 It is the auxiliary power supply overvoltage comparison logic diagram of the present invention; Figure 5 It is the auxiliary power supply undervoltage comparison logic diagram of the present invention; Figure 6 The invention discloses an optocoupler isolation circuit. DETAILED DESCRIPTION

[0016] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0017] like Figure 1-Figure 6 As shown, the technical solution adopted by the present invention is as follows: like Figure 1 As shown, an auxiliary power supply over-voltage and 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 optical coupling isolation circuit.

[0018] The auxiliary power supply port is connected to the input end of the detection sampling circuit, the input end of the comparison judgment circuit, and the input end of the optical coupling isolation circuit.

[0019] The output end of the detection sampling circuit is connected to the input end of the comparison judgment circuit.

[0020] The output end of the comparison judgment circuit is connected to the input end of the optical coupling isolation circuit.

[0021] The detection sampling circuit divides the auxiliary power supply voltage through two voltage-dividing resistors, outputs a sampling signal, and transmits it to the subsequent comparison and judgment circuit.

[0022] The comparison and judgment circuit compares the sampling signal with the reference voltage to judge the power supply status of the auxiliary power supply so as to transmit it to the subsequent optical coupling isolation circuit.

[0023] The optocoupler isolation circuit realizes electrical isolation between external input signals and internal control signals through optocoupler isolation, so that the central processing chip can perform related fault protection operations.

[0024] like Figure 2 As shown, the detection sampling circuit includes resistor R98, resistor R99, resistor R91, resistor R95, resistor R87, resistor R97, resistor R92, resistor R34, resistor R86, capacitor C25, capacitor C27, dip switch SW1, Pu1 port, Pu2 port, Pd1 port, and Pd2 port.

[0025] The auxiliary power supply port is connected to the output end of resistor R98, the input end of resistor R91, the input end of capacitor C25, the output end of resistor R97, the input end of resistor R92, and the input end of capacitor C27. The input end of resistor R98 is connected to the output end of resistor R99. The Pu1 port is connected to the input end of resistor R99. The output end of resistor R91 is connected to the input end of resistor R95. The output end of capacitor C25 is connected to the input end of resistor R87. The output end of resistor R95 and the output end of resistor R87 are connected to ground. The Pu2 port is connected between the output end of resistor R91 and the input end of resistor R95. The Pu2 port is connected between the output end of capacitor C25 and resistor R87. The Pd1 port is connected to the input end of resistor R97, the output end of resistor R92 is connected to the input end of resistor R34, the output end of capacitor C27 is connected to the input end of resistor R86, the output end of resistor R34 and the output end of resistor R86 are connected to ground, the Pd2 port is connected between the output end of resistor R92 and the input end of resistor R34, the Pd2 port is connected between the output end of capacitor C27 and the input end of resistor R86, pin 1 of dip switch SW1 is connected to Pu1 port, pin 2 of dip switch SW1 is connected to Pd1 port, pin 3 of dip switch SW1 is connected to Pd2 port, and pin 4 of dip switch SW1 is connected to Pu2 port.

[0026] Among them, the resistors R34, R86, R87, R91, R92, R95, R97, R98 and R99 all play a role in voltage division, but the above-mentioned voltage division resistors R87, R91, R95, R98 and R99 are only used to divide the auxiliary power supply V1 in the detection sampling circuit as the auxiliary power supply overvoltage comparison signal V Pu2 Transmitted to the inverting input terminal of the subsequent comparison and judgment circuit.

[0027] The remaining voltage-dividing resistors R34, R86, R92, and R97 are also used to divide the power supply V1 of the auxiliary power port, but their resistance values ​​are different from the voltage-dividing power supply overvoltage comparison signal V Pu2 The resistance values ​​of resistors R87, R91, R95, R98 and R99 are not the same, so the signal obtained by dividing the auxiliary power supply V1 by the 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 terminal of the subsequent comparison and judgment circuit.

[0028] In addition, the auxiliary power supply on the new energy vehicle has not only a 24V power supply voltage level, but also a 12V power supply voltage. Therefore, in order to improve the overall compatibility of the auxiliary power supply over-voltage and under-voltage detection and judgment circuit, a code switch SW1 is also used in the detection sampling circuit of the present invention to switch the series-parallel connection form of the voltage-dividing resistor in the detection sampling circuit to change the structure of the detection sampling circuit. It can be achieved that whether the detection sampling circuit of the present invention is used in a 12V auxiliary power supply system or in a 24V auxiliary power supply system, the overvoltage comparison signal V obtained by the voltage division of the corresponding voltage-dividing resistor is Pu2 Or undervoltage comparison signal V Pd2 No impact.

[0029] When the auxiliary power supply is 24V, the two channels inside the DIP switch SW1 are set to open circuit state, that is, the Pu1 port and the Pu2 port are not short-circuited, and the Pd1 port and the Pd2 port are not short-circuited, that is, the voltage is used to divide the overvoltage comparison signal V Pu2 The voltage divider resistors R98 and R99 are not connected in parallel to the voltage divider resistor R91, so the overvoltage comparison signal , undervoltage comparison signal .

[0030] When the auxiliary power supply is 12V, the two channels inside the DIP switch SW1 are set to the on state, that is, the Pu1 port is short-circuited with the Pu2 port, the Pd1 port is short-circuited with the Pd2 port segment, and the voltage divider resistors R98 and R99 are connected in parallel to the voltage divider resistor R91. Therefore, in this state , undervoltage comparison signal .

[0031] According to the above formula, V V1 The resistance values ​​of the voltage-dividing resistors R34, R86, R87, R91, R92, R95, R97, R98 and R99 are preset to maintain the overvoltage comparison signal V after changing the series-parallel structure of the voltage-dividing resistors through SW1. Pu2 and undervoltage comparison signal V Pd2 The purpose remains relatively unchanged, and ultimately the compatibility of the 12V auxiliary power supply and 24V auxiliary power supply detection sampling functions is achieved.

[0032] like Figure 3 As shown, the comparison and judgment circuit includes resistor R81, resistor R19, resistor R20, resistor R32, resistor R33, resistor R93, resistor 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.

[0033] The auxiliary power supply port is connected to the input end of the resistor R81, the output end of the resistor R81 is connected to the voltage reference source U6 pin 1, the voltage reference source U6 pin 2, and the input end of the resistor R19, the reference voltage port is connected to the input end of the resistor R19, the voltage reference source U6 pin 3, the output end of the resistor R19 is connected to the ground, the Pd2 port is connected to the input end of the resistor R20, the output end of the resistor R20 is connected to the in-phase input end of the first comparator and the input end of the resistor R93, and the output end of the resistor R93 is connected to the switching diode D19 The positive electrode is connected, the reference voltage port is connected to the input end of resistor R32, the output end of resistor R32 is connected to the inverting input end of the first comparator, the non-inverting input end of the second comparator, and the input end of resistor R94, the Pu2 port is connected to the input end of resistor R33, the output end of resistor R33 is connected to the inverting input end of the second comparator, the output end of resistor R94 is connected to the positive electrode of the switching diode D1, the output end of the first comparator is connected to the output end of the second comparator, the cathode of the switching diode D19, and the cathode of the switching diode D1.

[0034] The over-undervoltage detection and judgment circuit of the present invention is compatible with 12V auxiliary power supply and 24V auxiliary power supply, and the auxiliary power supply on the whole new energy vehicle is not a constant value, it will fluctuate between 12V or 24V as the vehicle runs, so the voltage reference source U6 is used in the comparison and judgment circuit to adjust the voltage to obtain the reference voltage Vref, so as to avoid the situation that the reference voltage Vref is unstable when the reference voltage Vref is obtained only through the voltage-dividing resistor R81 and the resistor R19. After the auxiliary power supply is input into the comparison and judgment circuit, the reference voltage Vref can be output through the voltage-dividing resistor R81 and the resistor R19. In addition to being output to the comparator U2, the reference voltage Vref is also transmitted to the pin 2 of the voltage reference source U6 for the voltage reference source U6 to do voltage regulation. When the reference voltage Vref is lower than the reference voltage in the voltage reference source U6, the anode and cathode of the voltage reference source U6 are in the off state, that is, the voltage reference source pin 1 and the voltage reference source pin 3 are not conducting. In this state, the voltage-dividing resistor R19 participates in the voltage division, thereby increasing the reference voltage Vref. On the contrary, when the reference voltage Vref is higher than the reference voltage in the voltage reference source U6, the anode and cathode of the voltage reference source U6 are in a conducting state, that is, the voltage reference source pin 1 and the voltage reference source pin 3 are conducting, and in this state, the voltage dividing resistor R19 does not participate in the voltage division, thereby reducing the reference voltage Vref. According to this principle, when the auxiliary power supply voltage value fluctuates, the reference voltage Vref can also maintain a stable effect.

[0035] In this comparison and judgment circuit, the first comparator and the second comparator form a dual-channel comparator, wherein channel one is composed of the same-phase input terminal of the first comparator, the inverting input terminal of the first comparator, and the output terminal of the first comparator, and is used for auxiliary power supply overvoltage comparison judgment in this comparison and judgment circuit, and channel two is composed of the same-phase input terminal of the second comparator, the inverting input terminal of the second comparator, and the output terminal of the second comparator, and is used for auxiliary power supply undervoltage comparison judgment in this comparison and judgment circuit. When the inverting input terminal of the second comparator receives the overvoltage comparison signal V output by the upper detection sampling circuit Pu2 After that, it will be compared with the reference voltage Vref received by the non-inverting input terminal of the second comparator.

[0036] like Figure 4 As shown, when the overvoltage comparison signal V Pu2 When the voltage is greater than the reference voltage Vref, the output of the second comparator will be flipped from high impedance to low impedance, that is, the auxiliary power supply overvoltage fault signal is output. Otherwise, the output of the second comparator maintains high impedance output.

[0037] In addition, in order to avoid the auxiliary power supply overvoltage fault signal being repeatedly output when the auxiliary power supply fluctuates above and below the overvoltage point, the comparison judgment circuit realizes the hysteresis comparison effect through the switching diode D19, the resistor R32, and the resistor R94. When the output end of the second comparator is flipped to a low-resistance output, under the action of the voltage-dividing resistor R32 and the resistor R94, the larger flip point of the second comparator will change from the reference voltage Vref to , thus the auxiliary power supply overvoltage comparison hysteresis effect can be achieved. And due to the unidirectional conductivity of the switching diode, when the output end of the second comparator is maintained at the high configuration output, the resistor R32 and the resistor R34 do not play a voltage dividing role. At this time, the lower voltage point of the second comparator does not change and is still the reference voltage Vref.

[0038] like Figure 5 As shown, similarly, when the non-inverting input terminal of the first comparator receives the undervoltage comparison signal V output by the upper detection sampling circuit Pd2 After that, it will be compared with the reference voltage Vref received by the inverting input terminal of the first comparator. Pd2 When the voltage is less than the reference voltage Vref, the output of the first comparator will be switched from high impedance to low impedance, that is, the auxiliary power supply undervoltage fault signal will be output. Otherwise, the high impedance output will be maintained. The hysteresis comparison effect in the undervoltage comparison judgment process is realized by resistors R93 and R20. When the output of the first comparator is switched to low impedance, the undervoltage comparison signal input to the in-phase input of the first comparator will be changed from V Pd2 becomes At this time, the corresponding flip-up voltage point of the first comparator changes from the reference voltage Vref to Thus, the comparison effect of the auxiliary power supply undervoltage hysteresis is achieved. Also due to the unidirectional conductivity of the switching diode, when the output end of the first comparator is maintained in a high-impedance output, the resistors R20 and R93 do not play a voltage dividing role. At this time, the undervoltage comparison signal V Pd2 No change.

[0039] To sum up, the comparison and judgment circuit can be used to process the auxiliary power supply overvoltage comparison signal, the auxiliary power supply undervoltage comparison signal to the auxiliary power supply overvoltage or undervoltage fault signal, thereby realizing the auxiliary power supply overvoltage or undervoltage judgment function and avoiding occupying the computing power resources of the central processing chip.

[0040] like Figure 6 As shown, the optocoupler isolation circuit includes a resistor R88, a resistor R79, a resistor R27, a capacitor C28, a capacitor C29, an isolation optocoupler U3, and a control signal port; The auxiliary power supply port is connected to the input end of resistor R88, the output end 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 end of the second comparator, resistor R79 is connected in parallel on both sides of pin 1 and pin 2 of the isolation optocoupler U3, capacitor C28 is connected in parallel on both sides of 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 end and control signal port of capacitor C29, the output end of capacitor C29 is connected to ground, and resistor R27 is connected in parallel across capacitor C29.

[0041] The auxiliary power port is connected to the input end of capacitor C87, and the output end of capacitor C87 is connected to the ground, which can stabilize the voltage and filter out noise.

[0042] A test point TP35 is connected between the control signal port and the input end of capacitor C29. The test point TP35 can monitor the signal status related to the auxiliary power supply over-voltage or under-voltage fault, and further determine whether the auxiliary power supply is working normally.

[0043] After the 12V or 24V auxiliary power supply is input to this optocoupler isolation circuit, it can be connected to the pin 1 of the isolation optocoupler U3 through the current limiting resistor R88. At this time, if the pin 2 of the isolation optocoupler U3 receives the auxiliary power supply over-voltage or under-voltage fault signal output by the upper comparison judgment circuit, that is, the pin 2 of the isolation optocoupler U3 is flipped to a low-resistance state, the primary light-emitting diode of the isolation optocoupler U3 is turned on, and a light signal of a certain wavelength and intensity is emitted at the same time. The light signal is transmitted inside the isolation optocoupler U3 based on the optical fiber as a medium. When it is transmitted to the secondary photosensitive transistor of the isolation optocoupler U3, it can drive the photosensitive transistor to turn on. Because the pin 4 of the isolation optocoupler U3 is connected to the +5V power supply, the pin 3 of the isolation optocoupler U3 is connected to the auxiliary power supply over-voltage or under-voltage control signal, that is, the collector and emitter of the secondary photosensitive transistor of the isolation optocoupler U3 are respectively connected to the +5V and auxiliary power supply over-voltage or under-voltage control signals. Therefore, after the secondary photosensitive transistor of the isolation optocoupler U3 is turned on, the auxiliary power supply over-voltage and under-voltage control signal can be pulled up to +5V. After the central processing chip detects the auxiliary power supply over-voltage and under-voltage control signal pulled up to 5V, the corresponding auxiliary power supply over-voltage and under-voltage protection operation can be executed.

[0044] Similarly, if pin 2 of the isolation optocoupler U3 does not receive the auxiliary power supply over-voltage or under-voltage fault signal output by the upper comparison and judgment circuit, that is, pin 2 of the isolation optocoupler U3 remains in a high-impedance state, the primary-side light-emitting diode of the isolation optocoupler is not turned on, and the secondary-side photosensitizer of the isolation optocoupler U3 is also in the off state. At this time, the auxiliary power supply over-voltage or under-voltage control signal is pulled down to GND through resistor R27 to prevent the central processing chip from erroneously executing the corresponding auxiliary power supply over-voltage or under-voltage protection operation due to interference.

[0045] In general, the auxiliary power supply over-voltage or under-voltage fault signal output by the comparison and judgment circuit is only transmitted to the primary side of the isolation optocoupler U3, and the corresponding auxiliary power supply over-voltage or under-voltage control signal is located at the secondary side of the isolation optocoupler U3. The primary side signal is isolated by the optocoupler to indirectly realize the on or off control of the secondary side phototransistor. The signal transmission between the primary and secondary sides of the optocoupler relies on optical signals, thereby realizing electrical isolation between the external input signal and the internal control signal.

[0046] The external input signal is an over-voltage or under-voltage fault signal output by the comparison judgment circuit, and the internal control signal is an over-voltage or under-voltage control signal output by the control signal port.

[0047] In summary, the present invention realizes the over-voltage and under-voltage detection and judgment function that is compatible with both 12V and 24V auxiliary circuit power supplies, and uses hardware circuits to perform auxiliary power supply over-voltage and under-voltage comparison and judgment, saving the corresponding central processing chip computing power resources. In addition, the external input signal and the internal control signal are electrically isolated.

[0048] Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments, or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. An auxiliary power supply over-voltage and under-voltage detection and judgment circuit for new energy vehicles, characterized in that: Including: auxiliary power port, detection sampling circuit, comparison judgment circuit, optocoupler isolation circuit; The auxiliary power supply port is connected to the input end of the detection sampling circuit, the input end of the comparison judgment circuit, and the input end of the optical coupling isolation circuit; the output end of the detection sampling circuit is connected to the input end of the comparison judgment circuit; and the output end of the comparison judgment circuit is connected to the input end of the optical coupling isolation circuit; The detection sampling circuit divides the auxiliary power supply voltage through two voltage-dividing resistors, outputs a sampling signal, and transmits it to the subsequent comparison and judgment circuit; The comparison and judgment circuit compares the sampling signal with the reference voltage to judge the power supply state of the auxiliary power supply.

2. The auxiliary power supply over-voltage and under-voltage detection and judgment circuit for new energy vehicles according to claim 1 is characterized in that: The detection sampling circuit includes a resistor R98, a resistor R99, a resistor R91, a resistor R95, a resistor R87, a resistor R97, a resistor R92, a resistor R34, a resistor R86, a capacitor C25, a capacitor C27, a dip switch SW1, a Pu1 port, a Pu2 port, a Pd1 port, and a Pd2 port; The auxiliary power supply port is connected to the output end of resistor R98, the input end of resistor R91, the input end of capacitor C25, the output end of resistor R97, the input end of resistor R92, and the input end of capacitor C27. The input end of resistor R98 is connected to the output end of resistor R99. The Pu1 port is connected to the input end of resistor R99. The output end of resistor R91 is connected to the input end of resistor R95. The output end of capacitor C25 is connected to the input end of resistor R87. The output end of resistor R95 and the output end of resistor R87 are connected to ground. The Pu2 port is connected between the output end of resistor R91 and the input end of resistor R95. The Pu2 port is connected between the output end of capacitor C25 and resistor R87. The Pd1 port is connected to the input end of resistor R97, the output end of resistor R92 is connected to the input end of resistor R34, the output end of capacitor C27 is connected to the input end of resistor R86, the output end of resistor R34 and the output end of resistor R86 are connected to ground, the Pd2 port is connected between the output end of resistor R92 and the input end of resistor R34, the Pd2 port is connected between the output end of capacitor C27 and the input end of resistor R86, pin 1 of dip switch SW1 is connected to Pu1 port, pin 2 of dip switch SW1 is connected to Pd1 port, pin 3 of dip switch SW1 is connected to Pd2 port, and pin 4 of dip switch SW1 is connected to Pu2 port.

3. The auxiliary power supply over-voltage and under-voltage detection and judgment circuit for new energy vehicles according to claim 2 is characterized in that: In the detection sampling circuit: The detection sampling circuit divides the auxiliary power supply voltage through two voltage-dividing resistors and uses them as detection sampling signals V Pu2 and detect the sampling signal V Pd2 , detect the sampling signal V Pu2, that is, the auxiliary power supply overvoltage comparison signal V Pu2 , detect the sampling signal V Pd2 That is, the auxiliary power supply undervoltage comparison signal V Pd2 ; The overvoltage comparison signal V is maintained after changing the series-parallel structure of the voltage divider resistors by using the DIP switch SW1 Pu2 , undervoltage comparison signal V Pd2 Relatively unchanged.

4. The auxiliary power supply over-voltage and under-voltage detection and judgment circuit for new energy vehicles according to any one of claims 2 or 3, characterized in that: The overvoltage comparison signal V is maintained after the voltage dividing resistor series-parallel structure is changed by the code switch SW1. Pu2 , undervoltage comparison signal V Pd2 The specific methods that remain relatively unchanged are: When the auxiliary power supply is 24V, the two channels inside the DIP switch SW1 are set to open circuit state, that is, the Pu1 port and the Pu2 port are not short-circuited, and the Pd1 port and the Pd2 port are not short-circuited, which are 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 to the voltage divider resistor R91, so the overvoltage comparison signal , undervoltage comparison signal ; When the auxiliary power supply is 12V, the two channels inside the DIP switch SW1 are set to the on state, that is, the Pu1 port is short-circuited with the Pu2 port, the Pd1 port is short-circuited with the Pd2 port segment, and the voltage divider resistors R98 and R99 are connected in parallel to the voltage divider resistor R91. Therefore, in this state , undervoltage comparison signal .

5. The auxiliary power supply over-voltage and under-voltage detection and judgment circuit for new energy vehicles according to claim 1 is characterized in that: The comparison judgment circuit includes a resistor R81, a resistor R19, a resistor R20, a resistor R32, a resistor R33, a resistor R93, a resistor 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 end of the resistor R81, the output end of the resistor R81 is connected to the voltage reference source U6 pin 1, the voltage reference source U6 pin 2, and the input end of the resistor R19, the reference voltage port is connected to the input end of the resistor R19, the voltage reference source U6 pin 3, the output end of the resistor R19 is connected to the ground, the Pd2 port is connected to the input end of the resistor R20, the output end of the resistor R20 is connected to the in-phase input end of the first comparator and the input end of the resistor R93, and the output end of the resistor R93 is connected to the switching diode D19 The positive electrode is connected, the reference voltage port is connected to the input end of resistor R32, the output end of resistor R32 is connected to the inverting input end of the first comparator, the non-inverting input end of the second comparator, and the input end of resistor R94, the Pu2 port is connected to the input end of resistor R33, the output end of resistor R33 is connected to the inverting input end of the second comparator, the output end of resistor R94 is connected to the positive electrode of the switching diode D1, the output end of the first comparator is connected to the output end of the second comparator, the cathode of the switching diode D19, and the cathode of the switching diode D1.

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

7. An auxiliary power supply over-voltage and under-voltage detection and judgment circuit for new energy vehicles according to any one of claims 1 or 5, characterized in that: The optocoupler isolation circuit includes a resistor R88, a resistor R79, a resistor R27, a capacitor C28, a capacitor C29, an isolation optocoupler U3, and a control signal port; The auxiliary power supply port is connected to the input end of resistor R88, the output end 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 end of the second comparator, resistor R79 is connected in parallel on both sides of pin 1 and pin 2 of the isolation optocoupler U3, capacitor C28 is connected in parallel on both sides of 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 end and control signal port of capacitor C29, the output end of capacitor C29 is connected to ground, and resistor R27 is connected in parallel across capacitor C29.

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

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