Charging pile power supply circuit of TBOX power supply

Abstract

The present invention discloses a charging pile power supply circuit for a TBOX power supply. The circuit includes an anti-reverse polarity diode D85, an anti-reverse polarity diode D86, a resettable fuse F5, a transient suppressor diode D87, an anti-reverse polarity diode D88, and an output capacitor C12. The positive and negative interfaces of the charging input of the charging pile are respectively connected to one input end of the resettable fuse F5 after passing through D85 and D86. The other end of the resettable fuse F5 is connected to the positive electrode of D88, the negative electrode of D88 is connected to one end of the capacitor C12, and the other end of the capacitor C12 is grounded. Power supply output terminals are respectively drawn from both ends of the capacitor C12, and the power supply output terminals are used to connect to the TBOX. A terminal is drawn between the resettable fuse F5 and D88 to connect to the negative electrode of the transient suppressor diode D87, and the positive electrode of the transient suppressor diode D87 is grounded. The circuit structure of the present invention is simple, and it can achieve normal power supply when the charging pile has abnormal high voltage fluctuations. After the circuit is damaged, it can detect faults immediately, give an alarm reminder, and promptly discover hardware faults in the circuit.

Description

Technical Field

[0001] The present invention relates to the field of safety protection of vehicle-mounted TBOX, and in particular to a TBOX power supply control circuit capable of withstanding abnormally high voltage input from a charging pile. Background Art

[0002] The TBOX itself can be powered by a DC charging station. When the car is charging, it is connected to the DC charging station. Pins 8 and 9 (A+-) of the DC charging station are responsible for powering the vehicle. According to the national standard GB_T 20234.3, the voltage range is 0-30V. However, due to the early stages of development, the quality of many charging stations varies greatly, and they cannot be guaranteed to fully comply with national standards. In many cases, they fail to meet the voltage range specified by national standards. This type of charging station, when charging, can endanger the normal operation and service life of the TBOX by supplying power to the TBOX. Commonly used solutions in existing technologies include the following three:

[0003] Solution 1: Ordinary TVS or lightning arrester solution, which can withstand short-term pulses exceeding 40V:

[0004] Disadvantages: Not resistant to AC or DC exceeding 40V.

[0005] Solution 2: Use an independent high-voltage DC / DC chip or a power supply with a transformer:

[0006] Disadvantages: It uses an additional independent power supply solution, which is more expensive.

[0007] Solution 3 uses an overvoltage protection solution. When the voltage exceeds a certain level, the power supply will be cut off:

[0008] Disadvantages: After overvoltage, the power supply is cut off and the charging pile cannot continue to supply power to the TBOX.

[0009] It can be seen that the solutions used in the prior art for resisting abnormally high pressure have many defects. Summary of the Invention

[0010] The purpose of the present invention is to overcome the deficiencies of the prior art and provide a new TBOX circuit control circuit that can withstand abnormally high voltage, so as to protect the safe power supply of the TBOX when the DC charging pile is supplying power.

[0011] In order to achieve the above-mentioned purpose, the technical solution adopted by the present invention is: a TBOX power supply circuit, which includes an anti-reverse polarity diode D85, an anti-reverse polarity diode D86, a self-recovery fuse F5, a transient suppression diode D87, an anti-reverse polarity diode D88 and an output capacitor C12. The positive and negative interfaces of the charging input of the charging pile (the positive electrode of the slow charging input interface and the positive electrode of the slow charging input interface) are respectively connected to one input end of the self-recovery fuse F5 after passing through the anti-reverse polarity diode D85 and the anti-reverse polarity diode D86. The other end of the self-recovery fuse F5 is connected to the positive electrode of the anti-reverse polarity diode D88, and the negative electrode of the anti-reverse polarity diode D88 is connected to one end of the capacitor C12. The other end of the capacitor C12 is grounded, and power supply output terminals are respectively drawn out at both ends of the capacitor C12, and the power supply output terminals are used to connect to the TBOX; a terminal is drawn out between the self-recovery fuse F5 and the anti-reverse polarity diode D88 to connect to the negative electrode of the transient suppression diode D87, and the positive electrode of the transient suppression diode D87 is grounded.

[0012] The control circuit also includes a fault detection module, which includes a diode D89, a capacitor C299, and a resistor R354. A wiring terminal is connected between the self-resettable fuse F5 and the anti-reverse polarity diode D88 to the cathode of the diode D89, and the anode of D89 is connected to the main control unit MCU. Terminals are connected between the anode of D89 and the main control unit MCU, which are grounded through resistor C299 and connected to the D3V3 MCU terminal through resistor R354. The main control unit MCU determines whether there is a fault in the power supply circuit at this time based on the input level signal.

[0013] The main control unit MCU is connected to the alarm system and is used to upload an alarm signal of a power supply circuit failure to the alarm system.

[0014] The alarm system includes a local alarm system, which includes an on-board instrument and / or an on-board display screen. The main control unit is connected to the on-board instrument or the on-board display screen respectively, and is used to control the on-board instrument or the on-board display screen to give an alarm signal indicating a power supply circuit failure.

[0015] The alarm system includes a remote alarm system, and the remote alarm system includes a background server. The main control unit is connected to the background server via a wireless network and is used to report a circuit fault signal to the background server.

[0016] The backend server is connected to the mobile terminal via a network and is used to send a fault alarm signal to the user's handheld terminal.

[0017] The power supply circuit further includes a car battery power supply branch, the two output ends of which are respectively connected to the two ends of capacitor C12 for supplying power to the TBOX via capacitor C12. The car battery power supply branch can automatically switch to supply power to the TBOX system.

[0018] The car battery power supply branch includes a car battery output module, a fuse F1, an anti-reverse polarity diode D1, and a transient suppression diode D2. The car battery power supply branch and the aforementioned charging pile power supply branch serve together as the source of power supply for the TBOX system. The output end of the car battery output module is connected to the positive electrode of the anti-reverse polarity diode D1 through the fuse F1. The negative electrode of the anti-reverse polarity diode D1 is connected between the anti-reverse polarity diode D88 and the capacitor C12. The negative electrode of the transient suppression diode D2 is connected between the anti-reverse polarity diode D1 and the fuse F1. The positive electrode of the transient suppression diode D2 is grounded.

[0019] The advantages of the present invention are: a simple circuit structure, which can realize normal power supply when the high voltage of the charging pile fluctuates abnormally, and can detect the fault immediately after the circuit is damaged, give an alarm reminder, and find the hardware fault of the circuit in time; and can also switch to the car battery to power the TBOX when the circuit powering the TBOX from the charging pile fails, thereby protecting the normal operation of the TBOX. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The following is a brief description of the contents and symbols in the drawings of the present invention:

[0021] Figure 1 This is a circuit schematic diagram of the power supply circuit of the present invention. DETAILED DESCRIPTION

[0022] The specific implementation of the present invention will be further explained in detail below by describing the best embodiment with reference to the accompanying drawings.

[0023] The present invention mainly focuses on the circuit design of the charging pile to power the TBOX during charging, to prevent the impact of abnormal high voltage on power supply safety. Figure 1 As shown, a TBOX power supply circuit includes an anti-reverse polarity diode D85, an anti-reverse polarity diode D86, a self-recovery fuse F5, a transient suppression diode D87, an anti-reverse polarity diode D88 and an output capacitor C12. The positive and negative interfaces of the charging input of the charging pile (the positive electrode of the slow charging input interface and the negative electrode of the slow charging input interface) are respectively connected to one input end of the self-recovery fuse F5 after passing through the anti-reverse polarity diode D85 and the anti-reverse polarity diode D86. The other end of the self-recovery fuse F5 is connected to the positive electrode of the anti-reverse polarity diode D88, and the negative electrode of the anti-reverse polarity diode D88 is connected to one end of the capacitor C12. The other end of the capacitor C12 is grounded, and power supply output terminals are respectively drawn out at both ends of the capacitor C12, and the power supply output terminals are used to connect to the TBOX; a terminal is drawn out between the self-recovery fuse F5 and the prevention diode D88 to connect to the negative electrode of the transient suppression diode D87, and the positive electrode of the transient suppression diode D87 is grounded.

[0024] The control circuit also includes a fault detection module, which includes a diode D89, a capacitor C299, and a resistor R354. A terminal is connected between the resettable fuse F5 and the reverse polarity protection diode D88 to the cathode of diode D89. The anode of D89 is connected to the main control unit MCU. Terminals are connected between the anode of D89 and the main control unit MCU, respectively, and are connected to ground through resistor C299 and to the D3V3_MCU terminal through resistor R354. D3V3_MCU is the network name of the MCU's 3.3V power supply, and serves as the pull-up power source for pull-up resistor R354. 1. When the charging pile power supply branch is intact, D89 is in a non-forward conduction state, and the signal CHRG_DGNS is taken from D3V3_MCU and is at a high level of 3.3V. 2. When the charging pile power supply branch is damaged and fails, D87 is damaged by a high voltage breakdown, and in this state, the 12V_SRC_IN signal is shorted to ground. At this point, D89 becomes forward-conducting, and the current flowing through D3V3_MCU through the pull-up resistor R354 flows forward through D89, then through the broken-down D87 to ground. At this point, the CHRG_DGNS signal is low (around 0.5V), and the MCU can use the CHRG_DGNS signal to determine whether the charging pile power supply branch is damaged. The main control unit MCU determines whether there is a fault in the power supply circuit based on the input level signal. When the circuit is normal, the MCU detects a high level, and when a fault occurs, the MCU detects a low level. The high and low levels determine whether there is a fault. The MCU can be implemented using the vehicle control unit (VCU), which detects the input voltage signal and issues an alarm signal.

[0025] The main control unit MCU is connected to the alarm system and is used to upload an alarm signal indicating a power supply circuit failure to the alarm system. Preferably, the alarm system includes a local alarm system and a remote alarm system. The local alarm system includes an onboard instrument and / or an onboard display. The main control unit is connected to the onboard instrument or the onboard display, respectively, to control the onboard instrument or the onboard display to generate an alarm signal indicating a power supply circuit failure.

[0026] The remote alarm system includes a backend server. The main control unit is connected to the backend server via a wireless network and reports circuit fault signals to the backend server. The backend server is also connected to mobile devices via the network to transmit fault alarm signals to the user's handheld device. Remote alarms directly send alarm signals to mobile phones, alerting vehicle owners to hardware circuit faults in a timely manner, facilitating timely action and repair. The backend server utilizes a cloud server to store and forward alarm data.

[0027] If the charging pile circuit that powers the TBOX fails during charging, the car battery will automatically switch to powering the TBOX to maintain operation. The two output terminals of the car battery branch are connected to capacitor C12 to power the TBOX. If the charging pile circuit fails, the car battery branch will automatically switch to powering the TBOX system.

[0028] The car battery power supply branch includes a car battery output module, a fuse F1, an anti-reverse polarity diode D1, and a transient suppression diode D2. The car battery power supply branch and the aforementioned charging pile power supply branch serve together as the source of power for the TBOX system. The output end of the car battery output module is connected to the positive electrode of the anti-reverse polarity diode D1 via the fuse F1. The negative electrode of the anti-reverse polarity diode D1 is connected between the anti-reverse polarity diode D88 and the capacitor C2. The negative electrode of the transient suppression diode D2 is connected between the anti-reverse polarity diode D1 and the fuse F1. The positive electrode of the transient suppression diode D2 is grounded. The car battery power supply branch and the aforementioned charging pile power supply branch serve together as the source of power for the TBOX system. When the charging pile power supply branch fails, 12V_SRC_IN will be short-circuited to ground due to the breakdown of D87. After the TBOX system power supply voltage drops below the car battery voltage, the car battery branch automatically switches to power the system through the anti-reverse polarity diode D1. And due to the function of the anti-reverse polarity diode D88, the power supply of the car battery branch will not be affected by the short circuit to ground of the charging pile power supply branch.

[0029] 1. This solution avoids the use of additional high-voltage DCDC chips and can withstand 98V DC

[0030] 2. After overvoltage, the critical protection state of the self-resettable fuse is used to limit the current to prevent the subsequent TVS from overcurrent burning, and the voltage clamping function of the subsequent TVS is activated to lock the voltage input to the system within an acceptable range.

[0031] 3. Even if the charging pile input circuit is damaged, it will not affect the continued operation of the entire TBOX system. The circuit damage status can be automatically reported to the background server through the wireless cellular network service, so that maintenance personnel will be aware of it.

[0032] like Figure 1 As shown, the basic unit description of the circuit diagram is:

[0033] 1. "SCHARGER" and "QCHARGER" are the slow-charge and fast-charge input positive terminals of the charging station's charging port; "12_BAT_IN" is the car battery input.

[0034] 2. "Output voltage +" and "Output voltage -" are the positive and negative voltages supplied to the subsequent circuit. The voltage of the subsequent circuit cannot exceed 40V, otherwise it will burn out.

[0035] 3. "Output to MCU" is used to identify the status of the charging circuit and then output it to the MCU. The MCU uses this signal to determine whether the charging pile input circuit is damaged. Under normal operating conditions, this signal is high (3.3V). If the charging pile input circuit is damaged, the signal is low.

[0036] 4. D1, D85, D86, and D88 are anti-reverse polarity diodes with a reverse voltage resistance of 200V.

[0037] 5. F5 is a resettable fuse that can limit overcurrent to around 100mA and has a withstand voltage of 60V. It will burn out if the voltage exceeds 60V.

[0038] 6. D87 is a transient voltage suppressor diode. If the reverse voltage exceeds 30V, a reverse leakage current of milliamperes will be observed. If the reverse leakage current exceeds 300mA, the D87 will burn out. If the reverse current does not exceed 300mA, the D87 can clamp the current across itself to around 38V.

[0039] Circuit principle description:

[0040] 1. Assuming that the voltage drop of the anti-reverse polarity diode is ignored, when the "SCHARGER" or "QCHARGER" input voltage exceeds 30V, D87 will gradually reverse conduct, and the conduction current will gradually increase as the input voltage rises.

[0041] 2. When the reverse conduction current of D87 exceeds 150mA, it will trigger F5 to enter the protection state and the input current will be limited to 100mA

[0042] 3. As the input voltage continues to rise, the D87 will not be burned out by the reverse current due to the current limiting function of F5. Until it reaches the reverse voltage clamping point of D87 at around 38V, the "output voltage +" and "output voltage -" provided to the subsequent stage will also be clamped at around 38V and will not rise further.

[0043] 4. If the input voltage continues to rise and exceeds 38V, D87 will not burn out due to the current limiting effect of F5, and D87 itself will clamp the voltage input to the subsequent stage at 38V, so the subsequent stage will not be damaged. Part of the current passing through F5 will leak through D87, and the remaining part can meet the normal power consumption of TBOX.

[0044] 5. The input voltage continues to rise, but does not exceed 38 + 60 = 98V. The subsequent circuits all operate normally without damage. This continues until the input exceeds 98V, exceeding the F5's withstand voltage range (60V). F5 burns out, shorting out. D87, due to the high voltage, burns out, shorting its negative terminal to ground. This causes a secondary burnout of F5, which completely fuses and disconnects it. The charging station's input circuit is damaged.

[0045] 6. If the charging pile input circuit is damaged, the MCU will be notified of the condition through the "output to MCU" signal (the level changes from high to low). However, due to the reverse connection protection of D1 and D88, the subsequent circuit can be powered by the car battery and continue to operate normally, and the current hardware damage status is reported to the backend server via the wireless cellular network.

[0046] The advantages of the present invention are: it can withstand 98V direct current; it uses simple passive components such as diodes, transistors, and fuses to build circuits, and does not require DCDC chips, inductors, and fuses; it will not cut off the power supply; even if the charging pile input circuit is damaged, it will not affect the continued operation of the entire TBOX system. The circuit damage status can be automatically reported to the background server through the wireless cellular network service, so that maintenance personnel are aware of it.

[0047] Obviously, the specific implementation of the present invention is not limited to the above-mentioned methods. As long as various non-substantial improvements are made using the method concept and technical solution of the present invention, they are all within the scope of protection of the present invention.

Claims

1. A charging pile power supply circuit for a TBOX power supply, characterized by: The circuit includes an anti-reverse polarity diode D85, an anti-reverse polarity diode D86, a resettable fuse F5, a transient suppression diode D87, an anti-reverse polarity diode D88, and an output capacitor C12. The positive and negative interfaces of the charging input of the charging pile are respectively connected to one input end of the resettable fuse F5 after passing through the anti-reverse polarity diode D85 and the anti-reverse polarity diode D86. The other end of the resettable fuse F5 is connected to the positive electrode of the anti-reverse polarity diode D88, and the negative electrode of the anti-reverse polarity diode D88 is connected to one end of the capacitor C12. The other end of the capacitor C12 is grounded. Power supply output terminals are respectively drawn out at both ends of the capacitor C12, and the power supply output terminals are used to connect to the TB OX; a terminal is connected to the negative electrode of the transient suppression diode D87 between the resettable fuse F5 and the anti-reverse polarity diode D88, and the positive electrode of the transient suppression diode D87 is grounded; the circuit also includes a fault detection module, the fault detection module includes an anti-reverse polarity diode D89, a capacitor C299, and a resistor R354, a terminal is connected to the negative electrode of the diode D89 between the resettable fuse F5 and the anti-reverse polarity diode D88, the positive electrode of D89 is connected to the main control unit MCU, and terminals are respectively connected between the positive electrode of D89 and the main control unit MCU, connected to the ground through the resistor C299, and connected to the D3V3_MCU power terminal through the resistor R354; The main control unit MCU determines whether there is a fault in the charging pile power supply circuit at this time based on the input level signal; when the charging pile power supply branch is not damaged, D89 is in a non-forward conduction state, and the signal CHRG_DGNS level is taken from D3V3_MCU. When the charging pile power supply branch is damaged and fails, D87 is broken down by high voltage, and D89 becomes a forward conduction state. The current of D3V3_MCU passes through D89 in the forward direction through the pull-up resistor R354, and then flows to the ground through the broken-down D87. At this time, the state of the signal CHRG_DGNS is low, and the MCU determines whether the charging pile power supply branch is damaged by the state of the signal CHRG_DGNS.

2. The charging pile power supply circuit of a TBOX power supply according to claim 1, characterized in that: The main control unit MCU is connected to the alarm system and is used to upload an alarm signal of a power supply circuit failure to the alarm system.

3. The charging pile power supply circuit of a TBOX power supply according to claim 2, characterized in that: The alarm system includes a local alarm system, which includes an on-board instrument and / or an on-board display screen. The main control unit is connected to the on-board instrument or the on-board display screen respectively, and is used to control the on-board instrument or the on-board display screen to give an alarm signal indicating a power supply circuit failure.

4. A charging pile power supply circuit for a TBOX power supply according to claim 2 or 3, characterized in that: The alarm system includes a remote alarm system, and the remote alarm system includes a background server. The main control unit is connected to the background server via a wireless network and is used to report a circuit fault signal to the background server.

5. The charging pile power supply circuit of a TBOX power supply according to claim 4, characterized in that: The backend server is connected to the mobile terminal via a network and is used to send a fault alarm signal to the user's handheld terminal.

6. A charging pile power supply circuit for a TBOX power supply according to any one of claims 1 to 3, characterized in that: The power supply circuit also includes a car battery power supply branch, the two output ends of which are respectively connected to the two ends of capacitor C12, for powering the TBOX through capacitor C12. The car battery power supply branch is used to automatically switch power supply when the charging pile power supply circuit fails.

7. The charging pile power supply circuit of a TBOX power supply according to claim 6, characterized in that: The car battery power supply branch includes a car battery output module, a fuse F1, an anti-reverse polarity diode D1, and a transient suppression diode D2. The output end of the car battery output module is connected to the positive electrode of the anti-reverse polarity diode D1 through the fuse F1, the negative electrode of the anti-reverse polarity diode D1 is connected between the anti-reverse polarity diode D88 and the capacitor C2, the negative electrode of the transient suppression diode D2 is connected between the anti-reverse polarity diode D1 and the fuse F1, and the positive electrode of the transient suppression diode D2 is grounded.

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