Driving control circuit and vehicle-mounted charger

Abstract

The embodiment of the utility model provides a driving control circuit and a vehicle-mounted charger, the driving control circuit comprises a rectification sampling circuit, an isolation signal generating circuit, an isolation signal receiving circuit, a comparison circuit and a driving circuit, the first sampling end of the rectification sampling circuit is connected with the first end of a charging interface; the second sampling end of the rectification sampling circuit is connected with the second end of the charging interface and the second end of the isolation signal generating circuit, the output end of the rectification sampling circuit is connected with the first end of the isolation signal generating circuit, and the output end of the isolation signal receiving circuit is connected with the first input end of the comparison circuit. The output end of the comparison circuit is connected with the first end of the drive circuit, the second end of the drive circuit is connected with the first end of a coil of the relay, the second end of the coil of the relay is connected with the positive electrode of the direct-current power source, the first contact of the relay is connected with the first end of the charging interface, and the second contact of the relay is connected with the alternating-current input end of the vehicle-mounted charger. The safety of the vehicle-mounted charger can be improved.

Description

Technical Field

[0001] This application relates to the field of electronic circuit technology, specifically to a drive control circuit and an on-board charger. Background Technology

[0002] With the increasing popularity of new energy vehicles, charging interfaces that share both AC and DC power have emerged. These interfaces allow both AC and DC power to be used simultaneously. However, allowing DC power to enter the on-board charger (OBC) can have very dangerous consequences. Currently, software is generally used to determine whether the charging interface is using high-voltage DC; if it is, the relay in the OBC will not engage. However, software methods can be flawed and prone to misjudgment, potentially allowing high-voltage DC power to enter the OBC, thus posing a safety risk. Utility Model Content

[0003] This application provides a drive control circuit and an on-board charger, which can improve the safety of the on-board charger.

[0004] A first aspect of this application provides a drive control circuit, including a rectifier sampling circuit, an isolation signal generating circuit, an isolation signal receiving circuit, a comparator circuit, and a drive circuit. The first sampling terminal of the rectifier sampling circuit is connected to the first terminal of a charging interface. The second sampling terminal of the rectifier sampling circuit is connected to the second terminal of the charging interface and the second terminal of the isolation signal generating circuit. The output terminal of the rectifier sampling circuit is connected to the first terminal of the isolation signal generating circuit. The output terminal of the isolation signal receiving circuit is connected to the first input terminal of the comparator circuit. The output terminal of the comparator circuit is connected to the first terminal of the drive circuit. The second terminal of the drive circuit is connected to the first terminal of a relay coil. The second terminal of the relay coil is connected to the positive terminal of a DC power supply. The first contact of the relay is connected to the first terminal of the charging interface, and the second contact of the relay is connected to the AC input terminal of an on-board charger.

[0005] The rectifier sampling circuit is used to sample the voltage between the first terminal and the second terminal of the charging interface;

[0006] The isolation signal generating circuit is used to generate a first isolation signal when the voltage between the first end of the charging interface and the second end of the charging interface is a DC voltage and is greater than a set threshold.

[0007] The isolation signal receiving circuit is configured to output a first signal to the first input terminal of the comparison circuit when the isolation signal generating circuit generates the first isolation signal.

[0008] The comparator circuit is configured to output a second signal to the first terminal of the drive circuit when the first signal is input to the first input terminal of the comparator circuit.

[0009] The driving circuit is used to control the first end of the coil and the second end of the coil to disconnect when the second signal is input to the first end of the driving circuit, so as to control the relay to be in an open state; the second signal is used to control the driving circuit to be in a non-driving state.

[0010] In this embodiment, a hardware circuit determines whether the voltage between the first and second ends of the charging interface is high-voltage DC. If it is determined to be high-voltage DC (the voltage between the first and second ends of the charging interface is a DC voltage and greater than a set threshold), an isolation signal generation circuit generates a first isolation signal, and an isolation signal receiving circuit outputs the first signal to the first input terminal of a comparator circuit. This causes the comparator circuit to output a second signal to the first terminal of a drive circuit. This second signal controls the drive circuit to be in a non-drive state, thereby disconnecting the first and second ends of the coil and controlling the relay to be in an open state. When the hardware circuit accurately determines that the voltage between the first and second ends of the charging interface is high-voltage DC, the relay is controlled to be in an open state, preventing high-voltage DC from being input to the AC input terminal of the on-board charger, thus improving the safety of the on-board charger.

[0011] Optionally, the drive control circuit further includes a control module, the output of which is connected to a third terminal of the drive circuit.

[0012] In this embodiment of the application, the control module can control the drive circuit to be in a driving state or a non-driving state.

[0013] Optionally, the isolation signal generating circuit is further configured to generate a second isolation signal when the voltage between the first end of the charging interface and the second end of the charging interface is a DC voltage and is less than the set threshold.

[0014] The isolation signal receiving circuit is further configured to output a third signal to the first input terminal of the comparison circuit when the isolation signal generating circuit generates the second isolation signal;

[0015] The comparator circuit is further configured to output a fourth signal to the first terminal of the drive circuit when the third signal is input to the first input terminal of the comparator circuit; the fourth signal is used to control the drive circuit to be in a drive state.

[0016] The driving circuit is further configured to control the generation of a conducting current between the first end of the coil and the second end of the coil when the fourth signal is input at the first end of the driving circuit and the control module outputs a fifth signal, so as to control the relay to be in a closed state; the fifth signal is used to control the driving circuit to be in a driving state.

[0017] In this embodiment, when the hardware circuit accurately determines that the voltage between the first and second terminals of the charging interface is low-voltage DC (the voltage between the first and second terminals of the charging interface is a DC voltage and less than the set threshold), the comparator circuit outputs a fourth signal. The relay is only controlled to be closed when both the fourth signal output by the comparator circuit and the fifth signal output by the control module are signals controlling the drive circuit to be in a driving state. The relay is controlled to be open when either the second signal output by the comparator circuit is a signal controlling the drive circuit to be in a non-driving state, or the seventh signal output by the control module is a signal controlling the drive circuit to be in a non-driving state. This improves the safety of the on-board charger.

[0018] Optionally, the isolation signal generating circuit is further configured to generate a third isolation signal when the voltage between the first end of the charging interface and the second end of the charging interface is an AC voltage.

[0019] The isolation signal receiving circuit is further configured to output a sixth signal to the first input terminal of the comparison circuit when the isolation signal generating circuit generates the third isolation signal;

[0020] The comparator circuit is further configured to output a fourth signal to the first terminal of the drive circuit when the sixth signal is input to the first input terminal of the comparator circuit; the fourth signal is used to control the drive circuit to be in a drive state.

[0021] The driving circuit is further configured to control the generation of a conducting current between the first end of the coil and the second end of the coil when the fourth signal is input at the first end of the driving circuit and the control module outputs a fifth signal, so as to control the relay to be in a closed state; the fifth signal is used to control the driving circuit to be in a driving state.

[0022] In this embodiment, when the hardware circuit accurately determines that the voltage between the first and second terminals of the charging interface is an AC voltage, the comparator circuit outputs a fourth signal. The relay is only controlled to be closed when both the fourth signal output by the comparator circuit and the fifth signal output by the control module are signals controlling the drive circuit to be in a driving state. The relay is controlled to be open when either the second signal output by the comparator circuit or the seventh signal output by the control module is a signal controlling the drive circuit to be in a non-driving state. This improves the safety of the on-board charger.

[0023] Optionally, the rectifier sampling circuit includes a first resistor, a first diode, and a first capacitor; the first end of the first resistor is connected to the first end of the charging interface, the second end of the first resistor is connected to the positive terminal of the first diode, the negative terminal of the first diode is connected to the first end of the first capacitor and the first end of the isolation signal generation circuit, and the second end of the first capacitor is connected to the second end of the charging interface.

[0024] Optionally, the isolation signal generation circuit includes a second resistor and an optocoupler light-emitting diode; the first end of the second resistor is connected to the output terminal of the rectifier sampling circuit, the second end of the second resistor is connected to the positive terminal of the light-emitting diode, and the negative terminal of the light-emitting diode is connected to the second terminal of the charging interface.

[0025] Optionally, the isolated signal receiving circuit includes a photosensitive device of the optocoupler, a third resistor, a fourth resistor, and a second capacitor; the first end of the fourth resistor is connected to the positive terminal of the DC power supply, the second end of the fourth resistor is connected to the first end of the third resistor, the first end of the second capacitor, and the first input terminal of the comparator circuit, the second end of the third resistor is connected to the first end of the photosensitive device, and the second end of the photosensitive device, the second end of the second capacitor, and the negative terminal of the DC power supply are grounded.

[0026] Optionally, the comparator circuit includes a fifth resistor, a sixth resistor, and an operational amplifier; the first end of the fifth resistor is connected to the positive terminal of the DC power supply, the second end of the fifth resistor is connected to the first end of the sixth resistor and the inverting input terminal of the operational amplifier, the non-inverting input terminal of the operational amplifier is connected to the output terminal of the isolated signal receiving circuit, the output terminal of the operational amplifier is connected to the first terminal of the driving circuit, the power supply pin of the operational amplifier is connected to the positive terminal of the DC power supply, and the second end of the sixth resistor, the ground pin of the operational amplifier, and the negative terminal of the DC power supply are grounded.

[0027] Optionally, the driving circuit includes a seventh resistor, an eighth resistor, a ninth resistor, a tenth resistor, and a switching transistor; the first end of the seventh resistor is connected to the output terminal of the control module, the second end of the seventh resistor is connected to the first end of the eighth resistor and the output terminal of the comparator circuit, the second end of the eighth resistor is connected to the first end of the ninth resistor and the control terminal of the switching transistor, the first end of the tenth resistor is connected to the first end of the relay coil, the second end of the tenth resistor is connected to the first end of the switching transistor, and the second end of the switching transistor and the second end of the ninth resistor are grounded.

[0028] A second aspect of this application provides an on-board charger, including the drive control circuit described in the first aspect of this application.

[0029] In this embodiment, when the voltage between the first end and the second end of the charging interface is high voltage DC through accurate hardware circuitry, the relay is controlled to be in the open state, so that the AC input terminal of the on-board charger will not receive high voltage DC, thereby improving the safety of the on-board charger. Attached Figure Description

[0030] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0031] Figure 1 This is a schematic diagram of the structure of a drive control circuit provided in an embodiment of this application;

[0032] Figure 2 This is a schematic diagram of the specific structure of a drive control circuit provided in an embodiment of this application;

[0033] Figure 3 This is a schematic diagram of another specific structure of the drive control circuit provided in the embodiments of this application;

[0034] Figure 4 This is a schematic diagram of the structure of an on-board charger provided in an embodiment of this application. Detailed Implementation

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

[0036] The terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish different objects, not to describe a specific order. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, system, product, or apparatus that comprises a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to these processes, products, or apparatuses.

[0037] In this application, the reference to "embodiment" means that a specific feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a mutually exclusive, independent, or alternative embodiment. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described in this application can be combined with other embodiments.

[0038] Please see Figure 1 , Figure 1 This is a schematic diagram of a drive control circuit provided in an embodiment of this application. Figure 1 As shown, the drive control circuit includes a rectifier sampling circuit 10, an isolation signal generation circuit 20, an isolation signal receiving circuit 30, a comparator circuit 40, and a drive circuit 50. The first sampling terminal of the rectifier sampling circuit 10 is connected to the first terminal of the charging interface. The second sampling terminal of the rectifier sampling circuit 10 is connected to the second terminal of the charging interface and the second terminal of the isolation signal generation circuit 20. The output terminal of the rectifier sampling circuit 10 is connected to the first terminal of the isolation signal generation circuit 20. The output terminal of the isolation signal receiving circuit 30 is connected to the first input terminal of the comparator circuit 40. The output terminal of the comparator circuit 40 is connected to the first terminal of the drive circuit 50. The second terminal of the drive circuit 50 is connected to the first terminal of the relay coil. The second terminal of the relay coil is connected to the positive terminal of the DC power supply. The first contact of the relay is connected to the first terminal of the charging interface. The second contact of the relay is connected to the AC input terminal of the on-board charger.

[0039] The rectifier sampling circuit 10 is used to sample the voltage between the first end of the charging interface and the second end of the charging interface;

[0040] The isolation signal generating circuit 20 is used to generate a first isolation signal when the voltage between the first end of the charging interface and the second end of the charging interface is a DC voltage and is greater than a set threshold.

[0041] The isolation signal receiving circuit 30 is used to output a first signal to the first input terminal of the comparison circuit 40 when the isolation signal generating circuit 20 generates the first isolation signal.

[0042] The comparator circuit 40 is used to output a second signal to the first terminal of the drive circuit 50 when the first signal is input to the first input terminal of the comparator circuit 40.

[0043] The driving circuit 50 is used to control the first end of the coil and the second end of the coil to disconnect when the second signal is input to the first end of the driving circuit 50, so as to control the relay to be in an open state; the second signal is used to control the driving circuit 50 to be in a non-driving state.

[0044] In this embodiment, the rectifier sampling circuit 10, the isolation signal generation circuit 20, the isolation signal receiving circuit 30, the comparator circuit 40, and the driver circuit 50 are all hardware circuits, without any software involvement.

[0045] The rectifier sampling circuit 10 can identify whether the voltage between the first end and the second end of the charging interface is a DC voltage or an AC voltage; when the voltage between the first end and the second end of the charging interface is a DC voltage, it can also identify whether the DC voltage is a high voltage DC (the voltage between the first end and the second end of the charging interface is a DC voltage and is greater than a set threshold) or a low voltage DC (the voltage between the first end and the second end of the charging interface is a DC voltage and is less than a set threshold).

[0046] The isolation signal generating circuit 20 and the isolation signal receiving circuit 30 are connected by an isolation signal. The isolation signal generating circuit 20 can isolate the voltage between the first end and the second end of the charging interface from the isolation signal receiving circuit 30, thereby avoiding interference from the voltage between the first end and the second end of the charging interface to the isolation signal receiving circuit 30, thus improving the safety of the on-board charger.

[0047] The DC power supply is a low-voltage DC power supply, which can provide DC power to the isolated signal receiving circuit 30, the comparator circuit 40, and the drive circuit 50. For example, the DC power supply can be a 12V DC power supply or a 5V DC power supply.

[0048] Both the first signal and the second signal are analog voltage signals. The first signal is input to the first input terminal of the comparator circuit 40, and a reference signal is input to the second input terminal of the comparator circuit 40. The voltage value of the reference signal is a fixed value. When the voltage between the first and second terminals of the charging interface is a high-voltage DC voltage (the voltage between the first and second terminals of the charging interface is a DC voltage and greater than a set threshold), the first input terminal of the comparator circuit 40 outputs the first signal, which allows the second signal output by the comparator circuit 40 to control the drive circuit 50 to be in a non-drive state.

[0049] The fact that the drive circuit 50 is in a non-drive state means that the drive circuit 50 cannot drive the relay to close.

[0050] When the drive circuit 50 is in the driving state, it means that the drive circuit 50 can drive the relay to close.

[0051] The charging port can connect a charging gun and an on-board charger. For example, the charging gun can be connected to an on-board charger via the charging port. The charging port can be a vehicle charging socket.

[0052] In this embodiment, a hardware circuit determines whether the voltage between the first and second ends of the charging interface is high-voltage DC. If it is determined to be high-voltage DC (the voltage between the first and second ends of the charging interface is a DC voltage and greater than a set threshold), an isolation signal generation circuit 20 generates a first isolation signal. An isolation signal receiving circuit 30 outputs this first signal to the first input terminal of a comparator circuit 40, causing the comparator circuit 40 to output a second signal to the first end of a drive circuit 50. This second signal controls the drive circuit 50 to be in a non-drive state, thereby disconnecting the first and second ends of the coil and controlling the relay to be in an open state. When the hardware circuit accurately determines that the voltage between the first and second ends of the charging interface is high-voltage DC, the relay is controlled to be in an open state, preventing high-voltage DC from being input to the AC input terminal of the on-board charger, thus improving the safety of the on-board charger.

[0053] Optional, such as Figure 1 As shown, the drive control circuit also includes a control module 60, the output of which is connected to the third terminal of the drive circuit 50.

[0054] In this embodiment, the control module 60 can control the drive circuit 50 to be in a driving state or a non-driving state. For example, the control module 60 can be a microcontroller unit (MCU) in an on-board charger.

[0055] It should be noted that the signal output from the control module 60 can control the drive circuit 50 to be in a driving or non-driving state, and the signal output from the comparator circuit 40 can also control the drive circuit 50 to be in a driving or non-driving state. When both the signal output from the control module 60 and the signal output from the comparator circuit 40 control the drive circuit 50 to be in a driving state, the relay is in a closed state. When either the signal output from the control module 60 or the signal output from the comparator circuit 40 controls the drive circuit 50 to be in a non-driving state, the relay is in an open state.

[0056] Optionally, the isolation signal generating circuit 20 is further configured to generate a second isolation signal when the voltage between the first end of the charging interface and the second end of the charging interface is a DC voltage and is less than the set threshold.

[0057] The isolation signal receiving circuit 30 is also used to output a third signal to the first input terminal of the comparison circuit 40 when the isolation signal generating circuit 20 generates the second isolation signal;

[0058] The comparator circuit 40 is further configured to output a fourth signal to the first terminal of the drive circuit 50 when the third signal is input to the first input terminal of the comparator circuit 40; the fourth signal is used to control the drive circuit 50 to be in a drive state.

[0059] The driving circuit 50 is further configured to control the generation of a conducting current between the first end of the coil and the second end of the coil when the fourth signal is input at the first end of the driving circuit 50 and the control module 60 outputs a fifth signal, so as to control the relay to be in a closed state; the fifth signal is used to control the driving circuit 50 to be in a driving state.

[0060] The third, fourth, and fifth signals are all analog voltage signals. The third signal is input to the first input terminal of the comparator circuit 40, and a reference signal is input to the second input terminal of the comparator circuit 40. The voltage value of the reference signal is fixed. When the voltage between the first and second terminals of the charging interface is low-voltage DC (the voltage between the first and second terminals of the charging interface is a DC voltage and less than a set threshold), the first input terminal of the comparator circuit 40 outputs the third signal, allowing the fourth signal output by the comparator circuit 40 to control the drive circuit 50 to be in a driving state. The fifth signal output from the control module 60 can also control the drive circuit 50 to be in a driving state, thereby controlling the relay to be in a closed state.

[0061] When the fifth signal output from the output terminal of the control module 60 controls the drive circuit 50 to be in the drive state, and the fourth signal output from the comparison circuit 40 controls the drive circuit 50 to be in the drive state, the relay is in the closed state.

[0062] In this embodiment, when the hardware circuit accurately determines that the voltage between the first and second terminals of the charging interface is low-voltage DC (the voltage between the first and second terminals of the charging interface is a DC voltage and less than the set threshold), the comparator circuit 40 outputs a fourth signal. The relay is only controlled to be closed when both the fourth signal output by the comparator circuit 40 and the fifth signal output by the control module 60 are signals controlling the drive circuit 50 to be in a driving state. The relay is controlled to be open when either the second signal output by the comparator circuit 40 is a signal controlling the drive circuit 50 to be in a non-driving state or the seventh signal output by the control module 60 is a signal controlling the drive circuit 50 to be in a non-driving state. This improves the safety of the on-board charger.

[0063] Optionally, the isolation signal generating circuit 20 is further configured to generate a third isolation signal when the voltage between the first end of the charging interface and the second end of the charging interface is an AC voltage.

[0064] The isolation signal receiving circuit 30 is also used to output a sixth signal to the first input terminal of the comparison circuit 40 when the isolation signal generating circuit 20 generates the third isolation signal;

[0065] The comparator circuit 40 is further configured to output a fourth signal to the first terminal of the drive circuit 50 when the sixth signal is input to the first input terminal of the comparator circuit 40; the fourth signal is used to control the drive circuit 50 to be in a drive state.

[0066] The driving circuit 50 is further configured to control the generation of a conducting current between the first end of the coil and the second end of the coil when the fourth signal is input at the first end of the driving circuit 50 and the control module 60 outputs a fifth signal, so as to control the relay to be in a closed state; the fifth signal is used to control the driving circuit 50 to be in a driving state.

[0067] The isolation signal generation circuit 20 can identify whether the voltage between the first terminal and the second terminal of the charging interface is AC or DC. The isolation signal generation circuit 20 can also identify whether the DC voltage between the first terminal and the second terminal of the charging interface is high-voltage DC or low-voltage DC when it is DC.

[0068] When the voltage between the first end and the second end of the charging interface is AC voltage or low-voltage DC, the comparator circuit 40 outputs a fourth signal.

[0069] In this embodiment, when the hardware circuit accurately determines that the voltage between the first and second terminals of the charging interface is an AC voltage, the comparator circuit 40 outputs a fourth signal. The relay is only controlled to be closed when both the fourth signal output by the comparator circuit 40 and the fifth signal output by the control module 60 are signals controlling the drive circuit 50 to be in a driving state. The relay is controlled to be open when either the second signal output by the comparator circuit 40 or the seventh signal output by the control module 60 is a signal controlling the drive circuit 50 to be in a non-driving state. This improves the safety of the on-board charger.

[0070] Please see Figure 2 , Figure 2 This is a schematic diagram of the specific structure of a drive control circuit provided in an embodiment of this application. For example... Figure 2 As shown, in Figure 1 Based on this, the rectifier sampling circuit 10 includes a first resistor R1, a first diode D1, and a first capacitor C1; the first end of the first resistor R1 is connected to the first end of the charging interface, the second end of the first resistor R1 is connected to the positive terminal of the first diode, the negative terminal of the first diode is connected to the first end of the first capacitor C1 and the first end of the isolation signal generation circuit 20, and the second end of the first capacitor C1 is connected to the second end of the charging interface.

[0071] In this embodiment, a first resistor R1, a first diode, and a first capacitor C1 are connected in series between the first and second terminals of the charging interface. When the voltage between the first and second terminals of the charging interface is during the positive half-cycle of the AC voltage, the first diode D1 conducts, and the voltage at the first terminal of the isolation signal generation circuit 20 is substantially the same as the voltage at the second terminal of the charging interface. When the voltage between the first and second terminals of the charging interface is during the negative half-cycle of the AC voltage, the first diode D1 is cut off, no current flows through the first capacitor C1, and there is no voltage at the first terminal of the isolation signal generation circuit 20.

[0072] Optional, such as Figure 2 As shown, the isolation signal generation circuit 20 includes a second resistor R2 and a light-emitting diode of an optocoupler U1; the first end of the second resistor R2 is connected to the output terminal of the rectifier sampling circuit 10 (e.g., Figure 2 As shown, the first end of the second resistor R2 is connected to the negative terminal of the first diode, the second end of the second resistor R2 is connected to the positive terminal of the light-emitting diode, and the negative terminal of the light-emitting diode is connected to the second end of the charging interface.

[0073] In this embodiment, when the voltage between the first and second ends of the charging interface is a DC voltage, the first diode D1 conducts. The current between the first and second ends of the charging interface flows through the first resistor R1, the second resistor R2, and the LED, causing the LED to conduct. The first resistor R1 and the second resistor R2 form a voltage divider circuit. The voltage across the first capacitor C1 is the same as the voltage across the second resistor R2 (the forward voltage drop of the LED is negligible). The voltage at the first end of the isolation signal generation circuit 20 (i.e., the voltage at the first end of the second resistor R2) is the voltage divided by the second resistor R2 (the forward voltage drop of the first diode and the LED is negligible), that is, the voltage V2 at the first end of the isolation signal generation circuit 20 = R2 * V1 / (R1 + R2), where V2 is the voltage at the first end of the isolation signal generation circuit 20 (i.e., the voltage at the first end of the second resistor R2), V1 is the voltage at the first end of the charging interface, R1 is the resistance value of the first resistor R1, and R2 is the resistance value of the second resistor R2. If V2 is greater than or equal to the forward voltage of the LED (for example, the forward voltage of an LED is typically around 0.7V), the LED emits light, and the isolation signal generation circuit 20 generates either a first isolation signal or a second isolation signal. Since the forward voltage of the LED is negligible, it can be assumed that the LED emits light as long as V1 is positive. The current flowing through the LED is closely related to the magnitude of V1. When V1 is greater than a set threshold, the current flowing through the LED is larger, and the light emitted by the LED is brighter. Therefore, the isolation signal generation circuit 20 generates a first isolation signal (which can be understood as a signal indicating brighter light emitted by the LED). When V1 is less than the set threshold, the current flowing through the LED is smaller, and the light emitted by the LED is dimmer. Therefore, the isolation signal generation circuit 20 generates a second isolation signal (which can be understood as a signal indicating dimmer light emitted by the LED).

[0074] When the voltage between the first and second terminals of the charging interface is an AC voltage, during the positive half-cycle of the AC voltage, the first diode D1 conducts. The current between the first and second terminals of the charging interface flows through the first resistor R1, the second resistor R2, and the LED, causing the LED to conduct. The first resistor R1 and the second resistor R2 form a voltage divider circuit. The voltage across the first capacitor C1 is the same as the voltage across the second resistor R2 (the forward voltage drop of the LED is negligible). The voltage at the first terminal of the isolation signal generation circuit 20 (i.e., the voltage at the first terminal of the second resistor R2) is the voltage divided by the second resistor R2 (the forward voltage drop of the first diode and the LED is negligible), that is, the voltage V2 at the first terminal of the isolation signal generation circuit 20 = R2 * V1 / (R1 + R2), where V2 is the voltage at the first terminal of the isolation signal generation circuit 20 (i.e., the voltage at the first terminal of the second resistor R2), V1 is the voltage at the first terminal of the charging interface, R1 is the resistance value of the first resistor R1, and R2 is the resistance value of the second resistor R2. If V2 is greater than or equal to the forward voltage of the LED (for example, the forward voltage of an LED is typically around 0.7V), the LED emits light, and the isolation signal generation circuit 20 generates a third isolation signal. During the negative half-cycle of the AC voltage, the first diode D1 is cut off, the LED cannot conduct, and the LED does not emit light. The isolation signal generation circuit 20 then generates the third isolation signal. The third isolation signal is a periodic signal: during the positive half-cycle of the AC voltage, the LED emits light (the brightness of the LED is positively correlated with the amplitude of the AC signal during the positive half-cycle); during the negative half-cycle of the AC voltage, the LED does not emit light. The third isolation signal can be understood as a signal indicating that the LED is in a cyclical state of emitting light for half a cycle and not emitting light for half a cycle.

[0075] Optional, such as Figure 2 As shown, the isolated signal receiving circuit 30 includes a photosensitive device of the optocoupler U1, a third resistor R3, a fourth resistor R4, and a second capacitor C2; the first end of the fourth resistor R4 is connected to the positive terminal of the DC power supply, the second end of the fourth resistor R4 is connected to the first end of the third resistor R3, the first end of the second capacitor C2, and the first input terminal of the comparator circuit 40, the second end of the third resistor R3 is connected to the first end of the photosensitive device, and the second end of the photosensitive device, the second end of the second capacitor C2, and the negative terminal of the DC power supply are grounded.

[0076] In this embodiment, both the photosensitive device and the light-emitting diode are components of the optocoupler U1. The photosensitive device can be a photodiode, a phototransistor, etc. Figure 2The photosensitive device is exemplified by a phototransistor. The principle of the optocoupler U1 is as follows: when the LED is conducting and emitting light, the photosensitive device conducts; when the LED is not conducting, it does not emit light, and the photosensitive device cannot conduct. The higher the brightness of the LED, the greater the conduction current of the photosensitive device.

[0077] When the photosensitive device is turned on, the third resistor R3 and the fourth resistor R4 form a voltage divider circuit. The voltage V4 at the first terminal of the third resistor R3 is V3*R3 / (R3+R4), where V4 is the voltage at the first terminal of the third resistor R3 (i.e., the voltage at the first input terminal of the comparator circuit 40), V3 is the voltage at the positive terminal of the DC power supply, R3 is the resistance value of the third resistor R3, and R4 is the resistance value of the fourth resistor R4.

[0078] When the photosensitive device is not conducting, and the second capacitor C2 is in a steady state, the voltage at the first terminal of the third resistor R3 is the voltage at the positive terminal of the DC power supply.

[0079] When the photosensitive device switches from non-conducting to conducting, the third resistor R3 and the fourth resistor R4 form a voltage divider circuit, the second capacitor C2 discharges through the photosensitive device, and the voltage at the first terminal of the third resistor R3 decreases. When the photosensitive device switches from conducting to non-conducting, the third resistor R3 and the fourth resistor R4 form a voltage divider circuit, the second capacitor C2 is in a charging state, and the voltage at the first terminal of the third resistor R3 increases.

[0080] When the voltage between the first end and the second end of the charging interface is a DC voltage and is greater than a set threshold, the isolation signal generation circuit 20 generates a first isolation signal, the light-emitting diode emits bright light, the photosensitive device has a large conduction current, the second capacitor C2 discharges rapidly through the photosensitive device, causing the voltage at the first end of the third resistor R3 to drop rapidly.

[0081] When the voltage between the first end of the charging interface and the second end of the charging interface is a DC voltage and is less than a set threshold, the isolation signal generation circuit 20 generates a second isolation signal, the light-emitting diode emits a dimmer light, the conduction current of the photosensitive device is small, the second capacitor C2 slowly discharges through the photosensitive device, causing the voltage at the first end of the third resistor R3 to slowly decrease.

[0082] When the voltage between the first end and the second end of the charging interface is an AC voltage, the isolation signal generation circuit 20 generates a third isolation signal, the light-emitting diode periodically turns on and off, the photosensitive device also periodically turns on and off, the second capacitor C2 periodically charges and discharges, causing the voltage at the first end of the third resistor R3 to periodically rise and fall.

[0083] Optional, such as Figure 2As shown, the comparator circuit 40 includes a fifth resistor R5, a sixth resistor R6, and an operational amplifier U2; the first end of the fifth resistor R5 is connected to the positive terminal of the DC power supply, the second end of the fifth resistor R5 is connected to the first end of the sixth resistor R6 and the inverting input terminal of the operational amplifier U2, and the non-inverting input terminal of the operational amplifier U2 is connected to the output terminal of the isolated signal receiving circuit 30 (e.g., ...). Figure 2 As shown, the non-inverting input terminal of operational amplifier U2 is connected to the first terminal of the third resistor R3, the output terminal of operational amplifier U2 is connected to the first terminal of the driving circuit 50, the power supply pin of operational amplifier U2 is connected to the positive terminal of the DC power supply, and the second terminal of the sixth resistor R6, the ground pin of operational amplifier U2, and the negative terminal of the DC power supply are grounded.

[0084] In this embodiment, the fifth resistor R5 and the sixth resistor R6 form a voltage divider circuit. The voltage V5 at the inverting input terminal of operational amplifier U2 is V3 * R6 / (R5 + R6), where V5 is the voltage at the inverting input terminal of operational amplifier U2 (i.e., the voltage at the first terminal of the sixth resistor R6), V3 is the voltage at the positive terminal of the DC power supply, R5 is the resistance value of the fifth resistor R5, and R6 is the resistance value of the sixth resistor R6. V5 and V3 are constant values.

[0085] Where V3 is greater than V4 and V5 is less than V3. V4 is the voltage at the non-inverting input of operational amplifier U2 (i.e., the voltage at the first terminal of the third resistor R3).

[0086] When the on-current of the photosensitive device is small, or when the photosensitive device periodically turns on and off, the voltage at the non-inverting input of operational amplifier U2 is greater than the voltage at the inverting input (i.e., V4 > V5), and the output signal of operational amplifier U2 is a high voltage. When the on-current of the photosensitive device is large, the voltage at the non-inverting input of operational amplifier U2 is less than the voltage at the inverting input (i.e., V4 < V5), and the output signal of operational amplifier U2 is a low voltage.

[0087] The threshold value can be preset. This threshold value is related to the values ​​of the first resistor R1, the second resistor R2, the third resistor R3, the fourth resistor R4, and the second capacitor C2. The resistance values ​​of the first resistor R1 and the second resistor R2 are related to the current of the LED. When the voltage between the first and second terminals of the charging interface is constant and the first diode D1 is conducting, the larger the sum of the resistance values ​​of the first resistor R1 and the second resistor R2, the smaller the current of the LED. The current of the LED is related to its luminous intensity. Within a certain current range (the normal operating current range of the LED), the current of the LED is positively correlated with its luminous intensity; that is, the larger the current of the LED, the higher its luminous intensity. The luminous intensity of the LED is also positively correlated with the current of the photosensitive device; that is, the higher the luminous intensity of the LED, the larger the current of the photosensitive device. Finally, the current of the photosensitive device is positively correlated with the discharge rate of the second capacitor C2; that is, the larger the current of the photosensitive device, the faster the discharge rate of the second capacitor C2. The discharge rate of the second capacitor C2 is negatively correlated with the rate of decrease of the voltage at the non-inverting input of the operational amplifier U2. That is, the faster the discharge rate of the second capacitor C2, the faster the rate of decrease of the voltage at the non-inverting input of the operational amplifier U2.

[0088] For example, the threshold can be set to 60V. Operational amplifier U2 will only output a low level when there is a DC voltage greater than 60V between the first and second ends of the charging interface.

[0089] Optional, such as Figure 2 As shown, the driving circuit 50 includes a seventh resistor R7, an eighth resistor R8, a ninth resistor R9, a tenth resistor R10, and a switching transistor Q1; the first end of the seventh resistor R7 is connected to the output terminal of the control module 60, and the second end of the seventh resistor R7 is connected to the first end of the eighth resistor R8 and the output terminal of the comparator circuit 40 (e.g., ...). Figure 2 As shown, the second end of the seventh resistor R7 is connected to the output terminal of the operational amplifier U2, the second end of the eighth resistor R8 is connected to the first end of the ninth resistor R9 and the control terminal of the switching transistor Q1, the first end of the tenth resistor R10 is connected to the first end of the coil of the relay, the second end of the tenth resistor R10 is connected to the first end of the switching transistor Q1, and the second end of the switching transistor Q1 and the second end of the ninth resistor R9 are grounded.

[0090] The switching transistor Q1 can be a low-level turn-on switching transistor, such as a positive channel Metal Oxide Semiconductor (PMOS) transistor or a PNP transistor.

[0091] In this embodiment, the eighth resistor R8 and the ninth resistor R9 can form a voltage divider resistor. The voltage V7 at the control terminal of the switch Q1 is V6*R9 / (R8+R9), where V7 is the voltage at the control terminal of the switch Q1 (i.e., the voltage at the first terminal of the ninth resistor R9), V6 is the voltage of the signal output from the output terminal of the operational amplifier U2, R8 is the resistance value of the eighth resistor R8, and R9 is the resistance value of the ninth resistor R9.

[0092] When both the output of operational amplifier U2 and the output of control module 60 are high voltage, V7 can turn off switch Q1, causing the relay to disconnect. When either the output of operational amplifier U2 or the output of control module 60 is low voltage, V7 can turn on switch Q1, causing the relay to close.

[0093] Among them, the seventh resistor R7 and the tenth resistor R10 can play the role of current limiting.

[0094] Please see Figure 3 , Figure 3 This is a schematic diagram of another specific structure of the drive control circuit provided in an embodiment of this application. For example... Figure 3 As shown, in Figure 2 On this basis, Figure 3 The comparator circuit 40 also includes an eleventh resistor R11, the two ends of which are connected to the non-inverting input terminal and the output terminal of the operational amplifier U2, respectively. The eleventh resistor R11 is a feedback resistor, which can reduce the nonlinear distortion and output impedance of the operational amplifier U2 and improve the output waveform of the operational amplifier U2.

[0095] Please see Figure 4 , Figure 4 This is a structural schematic diagram of an on-board charger provided in an embodiment of this application. Figure 4 As shown, the on-board charger 200 includes a drive control circuit 100. Among them, Figure 4 The drive control circuit 100 can be referred to the above. Figures 1 to 3 The description of the drive control circuit is omitted here.

[0096] like Figure 4 As shown, the first end of the charging interface can be connected to the DC positive terminal or live wire (DC+ / L) of the charging gun, and the second end of the charging interface can be connected to the DC negative terminal or neutral wire (DC- / N) of the charger. The charging interface can support both AC and DC charging simultaneously. Alternatively, it can support at least one of DC or AC charging. The charging gun can be either a DC charging gun or an AC charging gun.

[0097] In this embodiment, when the drive control circuit accurately determines that the voltage between the first end of the charging interface and the second end of the charging interface is high voltage DC, the relay is controlled to be in the open state, so that the AC input terminal of the on-board charger will not input high voltage DC, thereby improving the safety of the on-board charger.

[0098] In the above embodiments, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0099] In the several embodiments provided in this application, it should be understood that the disclosed drive control circuit can be implemented in other ways. For example, the drive control circuit embodiments described above are merely illustrative. For instance, the division of the units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed.

Claims

1. A drive control circuit, characterized in that, The device includes a rectifier sampling circuit, an isolation signal generation circuit, an isolation signal receiving circuit, a comparator circuit, and a driver circuit. The first sampling terminal of the rectifier sampling circuit is connected to the first terminal of the charging interface. The second sampling terminal of the rectifier sampling circuit is connected to the second terminal of the charging interface and the second terminal of the isolation signal generation circuit. The output terminal of the rectifier sampling circuit is connected to the first terminal of the isolation signal generation circuit. The output terminal of the isolation signal receiving circuit is connected to the first input terminal of the comparator circuit. The output terminal of the comparator circuit is connected to the first terminal of the driver circuit. The second terminal of the driver circuit is connected to the first terminal of the coil of a relay. The second terminal of the coil of the relay is connected to the positive terminal of a DC power supply. The first contact of the relay is connected to the first terminal of the charging interface. The second contact of the relay is connected to the AC input terminal of the on-board charger. The rectifier sampling circuit is used to sample the voltage between the first terminal and the second terminal of the charging interface; The isolation signal generating circuit is used to generate a first isolation signal when the voltage between the first end of the charging interface and the second end of the charging interface is a DC voltage and is greater than a set threshold. The isolation signal receiving circuit is configured to output a first signal to the first input terminal of the comparison circuit when the isolation signal generating circuit generates the first isolation signal. The comparator circuit is configured to output a second signal to the first terminal of the drive circuit when the first signal is input to the first input terminal of the comparator circuit. The driving circuit is used to control the first end of the coil and the second end of the coil to disconnect when the second signal is input to the first end of the driving circuit, so as to control the relay to be in an open state; the second signal is used to control the driving circuit to be in a non-driving state.

2. The drive control circuit according to claim 1, characterized in that, The drive control circuit also includes a control module, the output of which is connected to the third terminal of the drive circuit.

3. The drive control circuit according to claim 2, characterized in that, The isolation signal generating circuit is further configured to generate a second isolation signal when the voltage between the first end of the charging interface and the second end of the charging interface is a DC voltage and is less than the set threshold. The isolation signal receiving circuit is further configured to output a third signal to the first input terminal of the comparison circuit when the isolation signal generating circuit generates the second isolation signal; The comparator circuit is further configured to output a fourth signal to the first terminal of the drive circuit when the third signal is input to the first input terminal of the comparator circuit; the fourth signal is used to control the drive circuit to be in a drive state. The driving circuit is further configured to control the generation of a conducting current between the first end of the coil and the second end of the coil when the fourth signal is input at the first end of the driving circuit and the control module outputs a fifth signal, so as to control the relay to be in a closed state; the fifth signal is used to control the driving circuit to be in a driving state.

4. The drive control circuit according to claim 2, characterized in that, The isolation signal generating circuit is further configured to generate a third isolation signal when the voltage between the first end of the charging interface and the second end of the charging interface is an AC voltage. The isolation signal receiving circuit is further configured to output a sixth signal to the first input terminal of the comparison circuit when the isolation signal generating circuit generates the third isolation signal; The comparator circuit is further configured to output a fourth signal to the first terminal of the drive circuit when the sixth signal is input to the first input terminal of the comparator circuit; the fourth signal is used to control the drive circuit to be in a drive state. The driving circuit is further configured to control the generation of a conducting current between the first end of the coil and the second end of the coil when the fourth signal is input at the first end of the driving circuit and the control module outputs a fifth signal, so as to control the relay to be in a closed state; the fifth signal is used to control the driving circuit to be in a driving state.

5. The drive control circuit according to any one of claims 1 to 4, characterized in that, The rectifier sampling circuit includes a first resistor, a first diode, and a first capacitor; the first end of the first resistor is connected to the first end of the charging interface, the second end of the first resistor is connected to the positive terminal of the first diode, the negative terminal of the first diode is connected to the first end of the first capacitor and the first end of the isolation signal generation circuit, and the second end of the first capacitor is connected to the second end of the charging interface.

6. The drive control circuit according to any one of claims 1 to 4, characterized in that, The isolation signal generation circuit includes a second resistor and an optocoupler light-emitting diode; the first end of the second resistor is connected to the output terminal of the rectifier sampling circuit, the second end of the second resistor is connected to the positive terminal of the light-emitting diode, and the negative terminal of the light-emitting diode is connected to the second terminal of the charging interface.

7. The drive control circuit according to claim 6, characterized in that, The isolated signal receiving circuit includes a photosensitive device of the optocoupler, a third resistor, a fourth resistor, and a second capacitor; the first end of the fourth resistor is connected to the positive terminal of the DC power supply, the second end of the fourth resistor is connected to the first end of the third resistor, the first end of the second capacitor, and the first input terminal of the comparator circuit, the second end of the third resistor is connected to the first end of the photosensitive device, and the second end of the photosensitive device, the second end of the second capacitor, and the negative terminal of the DC power supply are grounded.

8. The drive control circuit according to any one of claims 1 to 4, characterized in that, The comparator circuit includes a fifth resistor, a sixth resistor, and an operational amplifier. The first end of the fifth resistor is connected to the positive terminal of the DC power supply. The second end of the fifth resistor is connected to the first end of the sixth resistor and the inverting input terminal of the operational amplifier. The non-inverting input terminal of the operational amplifier is connected to the output terminal of the isolated signal receiving circuit. The output terminal of the operational amplifier is connected to the first terminal of the driving circuit. The power supply pin of the operational amplifier is connected to the positive terminal of the DC power supply. The second end of the sixth resistor, the ground pin of the operational amplifier, and the negative terminal of the DC power supply are grounded.

9. The drive control circuit according to any one of claims 2 to 4, characterized in that, The driving circuit includes a seventh resistor, an eighth resistor, a ninth resistor, a tenth resistor, and a switching transistor; the first end of the seventh resistor is connected to the output terminal of the control module, the second end of the seventh resistor is connected to the first end of the eighth resistor and the output terminal of the comparator circuit, the second end of the eighth resistor is connected to the first end of the ninth resistor and the control terminal of the switching transistor, the first end of the tenth resistor is connected to the first end of the relay coil, the second end of the tenth resistor is connected to the first end of the switching transistor, and the second end of the switching transistor and the second end of the ninth resistor are grounded.

10. An on-board charger, characterized in that, Includes the drive control circuit as described in any one of claims 1 to 9.

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