Relay drive circuit and power module

Abstract

This application discloses a relay driving circuit and a power module, relating to the field of charging technology. The driving circuit includes a rectifier unit, a first delay unit, a second delay unit, a first voltage divider unit, a second voltage divider unit, and a driving unit. The first delay unit and the first voltage divider unit are connected in series and then in parallel between the first and second terminals of the rectifier unit. The second voltage divider unit and the second delay unit are connected in series and then in parallel between the second and third terminals of the rectifier unit. The first and second input terminals of the driving unit are connected to the two ends of the first voltage divider unit, the third input terminal of the driving unit is connected between the second voltage divider unit and the second delay unit, the first and second output terminals of the driving unit are connected to the two ends of the relay, and the second input terminal of the driving unit is grounded. This ensures the safety of the relay while driving it, reduces cost, and improves reliability.

Description

Technical Field

[0001] This application relates to the field of charging technology, and in particular to a relay drive circuit and a power module. Background Technology

[0002] In the driving technology of magnetic latching relays, external functional circuits are typically used to provide pulse signals to achieve the relay's engagement and disengagement operations. Since magnetic latching relays only require a momentary pulse to complete the state switching, applying a DC level for a long time will cause the coil to be continuously energized, leading to overheating or even burnout, and in severe cases, it may cause system failure or safety accidents.

[0003] Currently, there is a type of drive circuit that is supplied with positive or negative voltage levels from the outside and is driven by a relay to generate pulses to drive the relay. However, this type of circuit usually relies on a three-wire power supply architecture consisting of a positive power supply, a negative power supply, and a ground wire. The three-wire power supply architecture requires two independent control signals to achieve control and drive, and the circuit structure is complex with a large number of components. This not only increases the hardware cost but also introduces more failure points and reliability risks in practical applications. Utility Model Content

[0004] The main objective of this application is to provide a relay driving circuit and power module to ensure the safety of the relay while driving it, and to reduce costs and improve reliability.

[0005] To achieve the above objectives, this application provides a relay driving circuit, including a rectifier unit, a first delay unit, a second delay unit, a first voltage divider unit, a second voltage divider unit, and a driving unit; The positive and negative input terminals of the rectifier unit receive voltage signals. The first delay unit and the first voltage divider unit are connected in series and then in parallel between the first and second terminals of the rectifier unit. The second voltage divider unit and the second delay unit are connected in series and then in parallel between the second and third terminals of the rectifier unit. The first voltage divider unit and the second voltage divider unit are connected together and connected to the second terminal of the rectifier unit. The first and second input terminals of the driving unit are connected to the two ends of the first voltage divider unit, the third input terminal of the driving unit is connected between the second voltage divider unit and the second delay unit, the first and second output terminals of the driving unit are connected to the two ends of the relay, and the second input terminal of the driving unit is grounded.

[0006] Optionally, the first delay unit includes a first capacitor, the first voltage divider unit includes a first resistor, the second delay unit includes a second capacitor, and the second voltage divider unit includes a second resistor; one end of the first capacitor is connected to a first end of the rectifier unit, the other end of the first capacitor is connected to one end of the first resistor to form a first node, and the other end of the first resistor is connected to a second end of the rectifier unit; one end of the second resistor is connected to the other end of the first resistor, the other end of the second resistor is connected to one end of the second capacitor to form a second node, and the other end of the second capacitor is connected to a third end of the rectifier unit.

[0007] Optionally, the rectifier unit includes a first diode, a second diode, a third diode, a fourth diode, and a third capacitor; the anode of the first diode serves as the positive input terminal of the rectifier unit, the cathode of the first diode is connected to the cathode of the second diode, and the anode of the second diode serves as the negative input terminal of the rectifier unit; the cathode of the third diode is connected to the anode of the first diode, the anode of the third diode is connected to the anode of the fourth diode, and the cathode of the fourth diode is connected to the anode of the second diode; one end of the third capacitor is connected between the first diode and the second diode, and the other end of the third capacitor is connected between the third diode and the fourth diode.

[0008] Optionally, the driving circuit further includes a first clamping unit, which includes a fifth diode and a sixth diode; the cathode of the fifth diode is connected to the first node, and the anode of the fifth diode is connected to the second input terminal of the driving unit; the cathode of the sixth diode is connected to the second node, and the anode of the sixth diode is connected to the second input terminal of the driving unit.

[0009] Optionally, the first clamping unit includes a seventh diode and an eighth diode; the cathode of the seventh diode is connected to an external power supply, and the anode of the seventh diode is connected to the cathode of the fifth diode; the cathode of the eighth diode is connected to an external power supply, and the anode of the eighth diode is connected to the cathode of the sixth diode.

[0010] Optionally, the driving circuit further includes a second clamping unit, which includes a ninth diode and a tenth diode; the cathode of the ninth diode is connected to an external power supply, the anode of the ninth diode is connected to the cathode of the tenth diode, and the anode of the ninth diode is also connected to the first output terminal of the driving unit, while the anode of the tenth diode is grounded.

[0011] Optionally, the driving circuit further includes a third clamping unit, which includes an eleventh diode and a twelfth diode; the cathode of the eleventh diode is connected to an external power supply, the anode of the eleventh diode is connected to the cathode of the twelfth diode, and the anode of the eleventh diode is also connected to the first output terminal of the driving unit, while the anode of the twelfth diode is grounded.

[0012] Optionally, the voltage signal is issued by the controller of the charging system.

[0013] In addition, to achieve the above objectives, this application also provides a power module, including at least one drive circuit as described above, an AC / DC conversion circuit, and at least one DC / DC conversion circuit; the AC / DC conversion circuit and / or the DC / DC conversion circuit are provided with magnetic latching relays, and each magnetic latching relay is connected to one of the drive circuits.

[0014] Optionally, when the AC / DC conversion circuit includes the magnetic latching relay, each magnetic latching relay is disposed between the input terminal and the input capacitor of the AC / DC conversion circuit, and the magnetic latching relay is used in the AC / DC conversion circuit to control the AC / DC conversion circuit to achieve zero power consumption; when the DC / DC conversion circuit includes the magnetic latching relay, each magnetic latching relay is disposed at the output terminal of the DC / DC conversion circuit, and the magnetic latching relay is used in the DC / DC conversion circuit to control the series-parallel switching of multiple DC / DC conversion circuits.

[0015] The relay driving circuit of this application comprises a first delay unit, a first voltage divider unit, a second delay unit, and a second voltage divider unit, forming a symmetrical delay structure. When the rectifier unit receives a positive voltage signal, the first delay unit and the first voltage divider unit are connected in series to divide the voltage. The voltage at the first input terminal of the driving unit is equal to the voltage at the corresponding terminal of the first voltage divider unit, thereby turning on the driving unit and transmitting a driving voltage to the relay. As the voltage of the first delay unit gradually increases and the voltage of the first voltage divider unit gradually decreases, the voltage at the first input terminal of the driving unit also gradually decreases to the lower limit of the driving voltage. At this time, the driving unit turns off and stops transmitting the driving voltage, thus forming a pulse-type driving signal to drive the relay. The pulse-type driving method ensures the safety of the relay. The relay driving circuit of this application has a simple structure and uses a two-wire input for the external voltage signal, eliminating the need for logic control, thereby reducing costs and improving reliability. Attached Figure Description

[0016] Figure 1 This is one of the circuit diagrams of the driving circuit in the embodiments of this application; Figure 2This is a second circuit diagram of the driving circuit in an embodiment of this application; Figure 3 This is the third circuit diagram of the driving circuit in the embodiment of this application; Figure 4 This is the fourth circuit diagram of the driving circuit in the embodiment of this application; Figure 5 This is a circuit diagram of the power module according to an embodiment of this application; In the diagram, 110 is the rectifier unit; 120 is the first delay unit; 130 is the second delay unit; 140 is the first voltage divider unit; 150 is the second voltage divider unit; 160 is the driver unit; 170 is the first clamping unit; 180 is the second clamping unit; 190 is the third clamping unit; 510 is the AC / DC converter circuit; 520 is the DC / DC converter circuit; and 530 is the driver circuit.

[0017] The realization of the purpose, functional features and advantages of this application will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions 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, 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.

[0019] Magnetic latching relays (also known as "magnetic lock relays" or "pulse relays") have the significant advantage of extremely low power consumption because they only require a short electrical pulse to switch between engaging and disengaging states, and can maintain their state without continuous power supply after activation. They are widely used in fields with stringent power consumption requirements, such as smart meters, smart homes, new energy management, charging systems, and energy storage systems.

[0020] However, the operating characteristics of magnetic latching relays also place special and stringent requirements on their drive circuits: the drive signal must be a pulse with precisely controlled duration. Understandably, applying a prolonged DC level to the coil will cause it to remain continuously energized, leading to excessive power loss and rapid overheating, ultimately resulting in coil burnout, permanent relay damage, or even a cascading failure of the entire module or system. However, current drive circuits typically use continuous external voltage signals. When external devices provide voltage signals, the duration of the signal cannot be precisely controlled. To achieve precise control, programming is required to control the signal duration, but this method is complex and has limited applicability.

[0021] To meet the requirements of pulse driving, current drive circuits generally rely on external positive or negative voltage levels to generate pulses from a relay, which in turn drives the relay. While this approach achieves pulse driving functionality to some extent, it suffers from several inherent and significant drawbacks, resulting in high overall cost and insufficient reliability.

[0022] Specifically, existing drive circuits are quite complex, resulting in high costs. Furthermore, these circuits typically require a three-wire power supply architecture consisting of positive (+Vcc), negative (-Vcc), and ground (GND), making the circuit structure complex. Additionally, to achieve level shifting and pulse control, the circuit usually needs to use multiple MOSFETs (Metal-Oxide-Semiconductor Field-Effect Transistors), transistors, and passive components, resulting in a large number of components and further increasing production costs and space requirements.

[0023] Furthermore, the drive signals received by the circuit are entirely dependent on an external controller (such as an MCU). If the controller malfunctions due to program issues, electromagnetic interference (EMI), or software defects and outputs a continuous high or low level signal, the subsequent pulse generation circuit will fail, and the continuous level will be directly applied to the coil, inevitably leading to the burnout of the relay coil.

[0024] In summary, existing magnetic latching relay drive technology based on external level signals combined with discrete components to construct pulses has significant reliability shortcomings due to its complex circuit topology, numerous required components, high cost, heavy reliance on the correctness of external control, and lack of self-protection capability under abnormal conditions.

[0025] Therefore, this application provides a relay driving circuit and power module. The positive and negative levels are converted into pulses through a passive RC circuit and diodes to drive the magnetic latching relay. The pulse time is controllable, and even if a continuous external voltage signal is input, it will not affect the generation of subsequent pulses, thus improving the reliability of the driving circuit and the overall system. Furthermore, the driving circuit of this embodiment has a simple structure, with external positive and negative levels as dual-wire inputs, requiring no special control logic. Therefore, it can not only ensure the safety of the relay while driving it, but also effectively reduce costs.

[0026] Figure 2 This is one of the circuit diagrams of the driving circuit in the embodiments of this application.

[0027] like Figure 2As shown, the driving circuit of the relay may include a rectifier unit 110, a first delay unit 120, a second delay unit 130, a first voltage divider unit 140, a second voltage divider unit 150, and a driving unit 160.

[0028] The rectifier unit 110 receives voltage signals at its positive input terminal R+ and negative input terminal R-. The first delay unit 120 and the first voltage divider unit 140 are connected in series and then in parallel between the first terminal S1 and the second terminal S2 of the rectifier unit 110. The second voltage divider unit 150 and the second delay unit 130 are connected in series and then in parallel between the second terminal S2 and the third terminal S3 of the rectifier unit 110. The first voltage divider unit 140 and the second voltage divider unit 150 are connected and connected to the second terminal S2 of the rectifier unit 110. The first input terminal M1 and the second input terminal M2 of the drive unit 160 are connected to the two ends of the first voltage divider unit 140. The third input terminal M3 of the drive unit 160 is connected between the second voltage divider unit 150 and the second delay unit 130. The first output terminal M4 and the second output terminal M5 of the drive unit 160 are connected to the two ends of the relay. The second input terminal M2 of the drive unit 160 is grounded.

[0029] First, it should be noted that the driving circuit of this embodiment is a magnetic latching relay driving circuit, which can be applied in various application scenarios. As long as the circuit structure contains a magnetic latching relay, the driving circuit provided in this embodiment can be used to achieve pulse driving. For example, this driving circuit can be applied in a charging system. Many modules in a charging system have magnetic latching relays, such as the AC / AC conversion circuit and DC / DC conversion circuit of a power module. Therefore, the driving circuit of this embodiment can be applied in a charging system.

[0030] like Figure 2 As shown, the drive circuit in this embodiment is connected to an external power source or the AC power (i.e., voltage signal) output by a controller via two wires, and then converts the positive or negative voltage into positive and negative pulses. It should be noted that this voltage signal has a certain driving capability; it can not only turn on the drive unit 160 but also drive the switching of the magnetic latching relay. Furthermore, since the voltage signal is AC, the change in the positive or negative value of the voltage signal controls the relay's activation or deactivation. For example, when the voltage signal is positive, it controls the relay to activate; when the voltage signal is negative, it controls the relay to deactivate.

[0031] Specifically, the driving circuit includes a rectifier unit 110, a first delay unit 120, a second delay unit 130, a first voltage divider unit 140, a second voltage divider unit 150, and a driving unit 160. The rectifier unit 110 can be composed of multiple diodes; specifically, a currently available full-bridge rectifier circuit or a half-bridge rectifier circuit can be used as the rectifier unit 110 in this embodiment. Since the input positive and negative voltages need to power the driving unit 160, and the driving unit 160 can only receive DC power, a rectifier unit 110 is provided in the driving circuit in this embodiment. The rectifier unit 110 is mainly used to receive AC power from an external power source or controller input and rectify the AC power into DC power.

[0032] The first delay unit 120 and the second delay unit 130 can each be composed of at least one capacitor, while the first voltage divider unit 140 and the second voltage divider unit 150 can each be composed of at least one resistor. The first delay unit 120 and the first voltage divider unit 140 form an RC circuit, and the second delay unit 130 and the second voltage divider unit 150 also form an RC circuit, with these two RC circuits symmetrically distributed. Specifically, the first delay unit 120 and the first voltage divider unit 140 are connected in series and then in parallel in the upper half-bridge of the rectifier unit 110, while the second delay unit 130 and the second voltage divider unit 150 are connected in series and then in parallel in the lower half-bridge of the rectifier unit 110. The first delay unit 120, the second delay unit 130, the first voltage divider unit 140, and the second voltage divider unit 150 all serve to adjust the delay time.

[0033] The driving unit 160 may include a non-isolated driving chip. The first input terminal M1, the second input terminal M2, and the third input terminal M3 of the driving unit 160 can be three pins of the driving chip, and the first input terminal M1, the second input terminal M2, and the third input terminal M3 respectively correspond to Figure 2 The INA pin, GND pin, and INB pin are located in the driver unit 160. Similarly, the first output M4 and the second output M5 of the driver unit 160 can also correspond to... Figure 2 The OUTA and OUTB pins of the driver chip are connected to an external power supply, and the Vcc pin of the driver chip is connected to the external power supply. The first output terminal M4 and the second output terminal M5 of the driver unit 160 are respectively connected to the two ends of the winding of the magnetic latching relay. The driver unit 160 is used to output pulse signals to the magnetic latching relay.

[0034] It should be noted that the driver chip can be any existing in-phase driver chip. In some embodiments, when the INA pin of the driver chip is high, the OUTA pin is also high, and when the INB pin is low, the OUTB pin is also low. In some embodiments, a driver chip with the opposite logic can also be used. This application does not limit the logic of the driver chip.

[0035] This application uses a non-inverting driver chip as an example for subsequent description. For a non-inverting driver chip, as long as the levels of the INA and INB pins are inverted, the levels of the OUTA and OUTB pins will also be inverted. In practical applications, when the INA pin is high, the voltage of the OUTA pin is approximately equal to the voltage of the Vcc pin, and the voltage of the OUTB pin is approximately equal to the voltage of the GND pin; when the INB pin is high, the voltage of the OUTB pin is approximately equal to the voltage of the Vcc pin, and the voltage of the OUTA pin is approximately equal to the voltage of the GND pin.

[0036] When the input to the driving circuit is a positive voltage, that is, the positive input terminal R+ of the rectifier unit 110 is positively charged, and the voltage at the negative input terminal R- of the rectifier unit 110 is zero. The rectifier unit 110 outputs rectified DC power. The current is output from the first terminal S1 of the rectifier unit 110, passes through the first delay unit 120 and the first voltage divider unit 140, and then passes through the rectifier unit 110 to the negative input terminal R- of the rectifier unit 110, thus forming a loop. In this circuit, since the initial voltage of the capacitor in the first delay unit 120 is 0, the entire input voltage is applied to the first voltage divider unit 140. Furthermore, since the first voltage divider unit 140 is also connected in parallel between the first input terminal M1 and the second input terminal M2 of the drive unit 160, the voltage between the first input terminal M1 and the second input terminal M2 of the drive unit 160 is equal to the voltage across the first voltage divider unit 140. Therefore, at this time, the voltage at the first input terminal M1 of the drive unit 160 is at its highest, the second input terminal M2 is grounded at 0V, and the third input terminal M3 is connected to the negative input terminal R- of the rectifier unit 110 through the second delay unit 130; the voltage at the third input terminal M3 is also 0V. Correspondingly, the voltage at the first output terminal M4 of the drive unit 160 is V. Vcc The voltage at the second output terminal M5 is V. GND The voltage difference across the magnetic latching relay is approximately V. Vcc The relay clicks open.

[0037] Furthermore, as the capacitor in the first delay unit 120 charges, the voltage of the first delay unit 120 gradually increases. Correspondingly, the voltage of the first voltage divider unit 140 gradually decreases, and simultaneously, the voltage at the first input terminal M1 of the drive unit 160 also decreases until the voltage of the first voltage divider unit 140 drops to the start-up voltage of the drive unit 160. At this point, the drive unit 160 shuts down, and the voltage at the OUTA pin of the drive unit 160 becomes VGND. The drive unit 160 stops outputting current to the magnetic latching relay, the winding voltage of the magnetic latching relay becomes 0V, and the freewheeling current releases the winding energy. This achieves the output of a positive pulse signal to the magnetic latching relay, causing the magnetic latching relay to engage.

[0038] Conversely, when the input of the driving circuit is a negative voltage, that is, the voltage at the positive input terminal R+ of the rectifier unit 110 is 0, and the negative input terminal R- of the rectifier unit 110 receives a positive voltage; the rectifier unit 110 outputs rectified DC power, and the current is output from the third terminal S3 of the rectifier unit 110, passes through the second delay unit 130 and the second voltage divider unit 150, and then passes through the rectifier unit 110 to the positive input terminal R+ of the rectifier unit 110, thus forming a loop. In this circuit, since the initial voltage of the capacitor in the second delay unit 130 is 0V, the entire input voltage is applied to the second voltage divider unit 150. Furthermore, since the second voltage divider unit 150 is also connected in parallel between the second input terminal M2 and the third input terminal M3 of the drive unit 160, the voltage between these two terminals is equal to the voltage across the second voltage divider unit 150. Therefore, the voltage at the third input terminal M3 of the drive unit 160 is at its highest, the second input terminal M2 is grounded (0V), and the first input terminal M1 is connected to the positive input terminal R+ of the rectifier unit 110 through the first delay unit 120; the voltage at the first input terminal M1 is also 0V. Correspondingly, the voltage at the second output terminal M5 of the drive unit 160 is V. Vcc The voltage at the first output terminal M4 is V. GND The voltage difference across the magnetic latching relay is approximately -V. Vcc The relay disconnected.

[0039] Furthermore, as the capacitor in the second delay unit 130 charges, the voltage of the second delay unit 130 gradually increases. Correspondingly, the voltage of the second voltage divider unit 150 gradually decreases, and simultaneously, the voltage at the second input terminal M2 of the drive unit 160 also decreases until the voltage of the second voltage divider unit 150 drops to the start-up voltage of the drive unit 160. At this point, the drive unit 160 shuts down, and the voltage at the OUTB pin of the drive unit 160 becomes V. GND The drive unit 160 stops outputting voltage signals to the magnetic latching relay. This achieves the output of a reverse pulse signal to the magnetic latching relay, thereby turning off the magnetic latching relay.

[0040] It should be noted that the duration of the pulse signal can be determined by the relevant parameters of the capacitors and resistors in the first delay unit 120, the second delay unit 130, the first voltage divider unit 140, and the second voltage divider unit 150. For example, the larger the capacitance value of the capacitors in the first delay unit 120 and the second delay unit 130, the longer the pulse duration.

[0041] Therefore, by using the first delay unit 120, the second delay unit 130, the first voltage divider unit 140, and the second voltage divider unit 150, positive and negative voltage signals are converted into positive and negative pulse signals to drive the magnetic latching relay, ensuring the safety of the magnetic latching relay and achieving controllable pulse time. Furthermore, the drive circuit structure of this embodiment is simple, with external positive and negative levels as dual-wire inputs, and no switching transistors or other components are introduced, effectively reducing the cost of the drive circuit.

[0042] Figure 3 This is a second circuit diagram of the driving circuit in an embodiment of this application. For example... Figure 3 As shown, in some embodiments, the first delay unit 120 includes a first capacitor C1, the first voltage divider unit 140 includes a first resistor R1, the second delay unit 130 includes a second capacitor C2, and the second voltage divider unit 150 includes a second resistor R2.

[0043] In this configuration, one end of the first capacitor C1 is connected to the first terminal S1 of the rectifier unit 110, the other end of the first capacitor C1 is connected to one end of the first resistor R1 to form a first node N1, and the other end of the first resistor R1 is connected to the second terminal S2 of the rectifier unit 110; one end of the second resistor R2 is connected to the other end of the first resistor R1, the other end of the second resistor R2 is connected to one end of the second capacitor C2 to form a second node N2, and the other end of the second capacitor C2 is connected to the third terminal S3 of the rectifier unit 110.

[0044] In this embodiment, both the first delay unit 120 and the second delay unit 130 may include a capacitor, and both the first voltage divider unit 140 and the second voltage divider unit 150 may include a resistor. Specifically, the first capacitor C1 and the first resistor R1 are connected in series and then in parallel between the first terminal S1 and the second terminal S2 of the rectifier unit 110, and the first resistor R1 is connected to the second terminal S2 of the rectifier unit 110; correspondingly, the second capacitor C2 and the second resistor R2 are connected in series and then in parallel between the third terminal S3 and the second terminal S2 of the rectifier unit 110, and the second resistor R2 is connected to the second terminal S2 of the rectifier unit 110 and the first resistor R1.

[0045] Continue to refer to Figure 3 In some embodiments, the rectifier unit 110 includes a first diode D1, a second diode D2, a third diode D3, a fourth diode D4, and a third capacitor C3.

[0046] In this configuration, the anode of the first diode D1 serves as the positive input terminal R+ of the rectifier unit 110, the cathode of the first diode D1 is connected to the cathode of the second diode D2, and the anode of the second diode D2 serves as the negative input terminal R- of the rectifier unit 110; the cathode of the third diode D3 is connected to the anode of the first diode D1, the anode of the third diode D3 is connected to the anode of the fourth diode D4, and the cathode of the fourth diode D4 is connected to the anode of the second diode D2; one end of the third capacitor C3 is connected between the first diode D1 and the second diode D2, and the other end of the third capacitor C3 is connected between the third diode D3 and the fourth diode D4.

[0047] It should be noted that the capacitance of the third capacitor C3 is much greater than that of the first capacitor C1 and the second capacitor C2.

[0048] like Figure 3 As shown, it can be understood that the point on the left end of the third capacitor C3 (i.e. Figure 3 The voltage at point N0 (connected to the Vcc pin of the aforementioned driver chip) is the higher of the positive input terminal R+ and the negative input terminal R-, because the first diode D1 and the second diode D2 are in an "OR" relationship. Therefore, when the positive input terminal R+ of the rectifier unit 110 receives a positive voltage and the voltage at the negative input terminal R- is zero or negative, the first diode D1 conducts. Since the voltage at the negative input terminal R- is zero or negative, the fourth diode D4 conducts. At this time, the first diode D1, the third capacitor C3, and the fourth diode D4 form a circuit, achieving natural rectification. When the positive input terminal R+ of the rectifier unit 110 receives a zero or negative voltage and the negative input terminal R- receives a positive voltage, the second diode D2 conducts. Since the voltage at the positive input terminal R+ is zero or negative, the third diode D3 conducts. At this time, the second diode D2, the third capacitor C3, and the third diode D3 form a circuit, achieving natural rectification.

[0049] Furthermore, when the positive input terminal R+ of the rectifier unit 110 receives a positive voltage, and the voltage at the negative input terminal R- of the rectifier unit 110 is zero or negative, current will flow through the first capacitor C1, the first resistor R1, and the fourth diode D4 to form a circuit. Since the initial voltage of the first capacitor C1 is 0V, this positive voltage is entirely applied to the first resistor R1. Correspondingly, the INA pin of the driver chip is also at high voltage, and the driver chip conducts and outputs a voltage signal to the subsequent stage. As the voltage of the first capacitor C1 gradually increases, the voltage across the first resistor R1 gradually decreases until the voltage of the first resistor R1 drops to the lower input limit of the driver chip. At this point, the driver chip turns off, the voltage at the INA pin of the driver chip equals the voltage at the GND pin, the relay winding voltage is 0V, and the freewheeling current releases the winding energy. In addition, the voltage of the first capacitor C1 will remain at the positive input voltage, while the voltage of the second capacitor C2 will be 0V.

[0050] As an example, if the lower input limit of the driver chip is 6V, the positive input terminal R+ of the rectifier unit 110 receives a positive voltage of 12V, and the negative input terminal R- receives a voltage of 0V. Initially, the voltage across the first capacitor C1 is 0V, and the voltage across the first resistor R1 is 12V. As the voltage across the first capacitor C1 gradually increases and the voltage across the first resistor R1 gradually decreases to 6V, the driver chip turns on and outputs a voltage signal to the subsequent stages. When the voltage across the first resistor R1 decreases to 6V or below, the driver chip turns off.

[0051] Conversely, when the negative input terminal R- of rectifier unit 110 receives a positive voltage, and the voltage at the positive input terminal R+ of rectifier unit 110 is zero or negative, current will flow through the second capacitor C2, the second resistor R2, and the third diode D3 to form a circuit. Since the initial voltage of the second capacitor C2 is 0V, this positive voltage is entirely applied to the second resistor R2. Correspondingly, the INB pin of the driver chip is also at high voltage, and the driver chip conducts and outputs a voltage signal to the subsequent stage. As the voltage of the second capacitor C2 gradually increases, the voltage across the second resistor R2 gradually decreases until the voltage of the second resistor R2 drops to the lower input limit of the driver chip. At this point, the driver chip turns off, the voltage at the INB pin of the driver chip equals the voltage at the GND pin, the relay winding voltage is 0V, and the freewheeling current releases the winding energy.

[0052] The above-described driving circuit operates under ideal conditions. However, in practical applications, special conditions may arise: First, the initial voltage of the second capacitor C2 is not 0V. Second, the rectifier unit 110 receives AC power, therefore the voltages at its positive input terminal R+ and negative input terminal R- are constantly changing. When the input voltage switches between positive and negative, either the first capacitor C1 or the second capacitor C2 undergoes a charging cycle, so its voltage is no longer 0V and it needs to be discharged. Both of these situations can potentially damage the driving chip.

[0053] Therefore, this embodiment adds a first clamping unit 170 to the driving circuit to keep the voltage of the INA pin and INB pin of the driving chip clamped at V. Vcc To V GND This ensures the safety of the driver chip and the reliability of the driver circuit.

[0054] Figure 4 This is the third circuit diagram of the driving circuit in the embodiment of this application, as shown below. Figure 4 As shown, in some embodiments, the driving circuit further includes a first clamping unit 170, which may include a fifth diode D5, a sixth diode D6, a seventh diode D7, and an eighth diode D8.

[0055] In this configuration, the cathode of the fifth diode D5 is connected to the first node N1, and the anode of the fifth diode D5 is connected to the second input terminal M2 of the driving unit 160; the cathode of the sixth diode D6 is connected to the second node N2, and the anode of the sixth diode D6 is connected to the second input terminal M2 of the driving unit 160; the cathode of the seventh diode D7 is connected to an external power supply, and the anode of the seventh diode D7 is connected to the cathode of the fifth diode D5; the cathode of the eighth diode D8 is connected to an external power supply, and the anode of the eighth diode D8 is connected to the cathode of the sixth diode D6.

[0056] Understandably, when the positive input terminal R+ of rectifier unit 110 receives a positive voltage, and the voltage at the negative input terminal R- of rectifier unit 110 is zero or negative, and current forms a circuit through the first capacitor C1, the first resistor R1, and the fourth diode D4, once the fourth diode D4 conducts, since the voltage across the fourth diode D4 is approximately 0V, the fourth diode D4 will clamp the voltage of the second resistor R2 and the second capacitor C2 to 0V. If the initial voltage of the second capacitor C2 is not 0V at this time, the second capacitor C2 will discharge due to the clamping of the fourth diode D4. When the second capacitor C2 discharges, there is a negative voltage across the second resistor R2, and the voltage at the INB pin of the driver chip is the same as the voltage across the second capacitor C2, so there will also be a negative voltage at the INB pin. However, the INB pin of the driver chip usually does not receive negative voltage, which may cause damage to the driver chip. Furthermore, when the second resistor R2 is at a negative voltage and the first resistor R1 is at a positive voltage, the GND pin of the driver chip, the fourth diode D4, and the negative input terminal R- of the rectifier unit 110 are not connected. The current input to the positive input terminal R+ of the rectifier unit 110 will flow to the negative input terminal R- through the branch containing the first capacitor C1, the first resistor R1, the second resistor R2, and the second capacitor C2. The voltage of the INB pin is equal to the voltage of the GND pin. However, since the GND pin is not connected to the negative input terminal R- of the rectifier unit 110, the voltage of the GND pin is equal to the voltage across the second resistor R2. Since the voltage across the second resistor R2 is negative, the INB pin is also negative, which will further damage the driver chip.

[0057] Based on this, in this embodiment, a sixth diode D6 is connected in parallel across the second resistor R2. When the second capacitor C2 discharges, the forward current flowing from the first capacitor C1 and the first resistor R1 will flow through the sixth diode D6. At this time, the sixth diode D6 bypasses the second resistor R2, and the voltage at the INB pin is approximately equal to the voltage at the sixth diode D6. Since the voltage drop across the sixth diode D6 is very small, the voltage at the INB pin is approximately 0V, thereby clamping the voltage at the INB pin to V. Vcc To V GND between.

[0058] When the driving circuit receives a reverse voltage signal (i.e., the negative input terminal R- of the rectifier unit 110 receives a positive voltage, and the voltage at the positive input terminal R+ is zero or negative), the fifth diode D5 performs the same function as the sixth diode D6 mentioned above, which will not be elaborated here.

[0059] Furthermore, it can be understood that when the driving circuit receives a positive voltage signal, the first capacitor C1 undergoes a charging cycle, and its voltage is the input positive voltage. During AC conversion, i.e., when the input voltage signal of the driving circuit changes from positive to negative, the negative input terminal R- of the rectifier unit 110 receives a positive voltage signal, and current flows through the second capacitor C2, the second resistor R2, and the third diode D3 to form a circuit. However, since the voltage of the first capacitor C1 is the input positive voltage, it needs to discharge. At this time, the external input reverse voltage and the voltage of the first capacitor C1 discharge are connected in series to form a double voltage applied to the second capacitor C2, the first resistor R1, and the second resistor R2. However, because a fifth diode D5 is connected in anti-parallel to the first resistor R1, the voltage of the first resistor R1 can be clamped to approximately 0V. Therefore, double the voltage is applied to the second resistor R2, resulting in overvoltage at the INB pin.

[0060] Therefore, in this embodiment, an eighth diode D8 is provided on the driving circuit to clamp the voltage of the INB pin to V. Vcc .

[0061] It should be noted that when the input voltage signal of the drive circuit changes from positive to negative, current flows through the second capacitor C2, the second resistor R2, and the fifth diode D5 to the first capacitor C1. Since this voltage is reversed, while the voltage of the first capacitor C1 is forward, the current in the first capacitor C1 is gradually released. When the voltage of the first capacitor C1 drops to 0V, the current input to the negative input terminal R- of the rectifier chip flows through the second capacitor C2, the second resistor R2, and the third diode D3 to the positive input terminal R+ of the rectifier chip, forming a loop.

[0062] When the driving circuit receives a positive voltage signal again, the seventh diode D7 performs the same function as the eighth diode D8 mentioned above, which will not be elaborated here.

[0063] In practical applications, the driver chip may experience power outages, resulting in undervoltage on its Vcc pin and causing it to malfunction. In this situation, the driver chip's OUTA and OUTB pins have no output, and are disconnected from the relay coil. The relay's inductance generates a reverse voltage, which is output to the driver chip. This reverse voltage can easily damage the driver chip.

[0064] Therefore, in this embodiment of the application, a second clamping unit 180 and a third clamping unit 190 are further provided in the driving circuit to clamp the voltage of the OUTA pin and the OUTB pin at V. Vcc To V GND Even when the OUTA and OUTB pins output a high impedance state (i.e., an abnormality), the second clamping unit 180 and the third clamping unit 190 can still rectify the power to the Vcc capacitor of the driver chip through natural rectification.

[0065] Figure 5 This is the fourth circuit diagram of the driving circuit in the embodiment of this application, as shown below. Figure 5 As shown, in some embodiments, the drive circuit further includes a second clamping unit 180 and a third clamping unit 190.

[0066] The second clamping unit 180 includes a ninth diode D9 and a tenth diode D10; the cathode of the ninth diode D9 is connected to an external power supply, the anode of the ninth diode D9 is connected to the cathode of the tenth diode D10, and the anode of the ninth diode D9 is also connected to the first output terminal M4 of the drive unit 160, while the anode of the tenth diode D10 is grounded.

[0067] The third clamping unit 190 includes an eleventh diode D11 and a twelfth diode D12; the cathode of the eleventh diode D11 is connected to an external power supply, the anode of the eleventh diode D11 is connected to the cathode of the twelfth diode D12, and the anode of the eleventh diode D11 is also connected to the first output terminal M4 of the drive unit 160, and the anode of the twelfth diode D12 is grounded.

[0068] The voltage of the OUTA and OUTB pins can be clamped at V using diodes D9 (ninth), D10 (tenth), D11 (eleventh), and D12 (twelfth). Vcc To V GND This prevents damage to the driver chip.

[0069] Therefore, by using a passive RC circuit and diodes to convert positive and negative voltage levels into pulses, the magnetic latching relay can be driven, and the pulse duration is controllable. Furthermore, the drive circuit is simple, mostly implemented using passive RC circuits and diodes, requiring lower reliability of the drive chip. Additionally, the external positive and negative voltage levels are two-wire inputs. The drive circuit in this embodiment does not require control logic to directly achieve pulse drive with controllable pulse duration, thus making it more versatile.

[0070] Based on the above embodiments, this application also provides a power module, which may include at least one drive circuit 530 as described above, an AC / DC conversion circuit 510, and at least one DC / DC conversion circuit 520; the AC / DC conversion circuit 510 and / or the DC / DC conversion circuit 520 are provided with magnetic latching relays, and each magnetic latching relay is connected to a drive circuit 530.

[0071] Figure 5 This is a circuit diagram of the power module according to an embodiment of this application. Figure 5 As shown, in some embodiments, when there are magnetic latching relays in the AC / DC conversion circuit 510, each magnetic latching relay is disposed between the input terminal of the AC / DC conversion circuit 510 and the input capacitor. The magnetic latching relays in the AC / DC conversion circuit 510 are used to control the AC / DC conversion circuit 510 to achieve zero power consumption.

[0072] In the case of a magnetic latching relay in the DC / DC converter circuit 520, each magnetic latching relay is set at the output terminal of the DC / DC converter circuit 520. The magnetic latching relay is used in the DC / DC converter circuit 520 to control the series-parallel switching of multiple DC / DC converter circuits 520.

[0073] Specifically, a magnetic latching relay can be installed between the AC input side and the input capacitor of the AC / DC conversion circuit 510. When the power module is not working, the magnetic latching relay can be disconnected, thereby achieving zero power consumption of the power module. The magnetic latching relay can be connected to a drive circuit 530 provided in this embodiment and driven by the drive circuit 530 to achieve engagement and disengagement.

[0074] In some embodiments, a magnetic latching relay can also be provided on the DC input side of the DC / DC converter circuit 520. When the power module is not working, the magnetic latching relay can be disconnected to achieve zero power consumption of the power module. Similarly, the magnetic latching relay can be connected to a drive circuit 530 provided in this embodiment and driven by the drive circuit 530 to achieve engagement and disengagement.

[0075] like Figure 5 As shown, multiple magnetic latching relays (i.e., Figure 5 (K1 to K4) These magnetic latching relays can be used to switch between series and parallel DC outputs, thereby controlling the output power of the power module. Each of these magnetic latching relays can be connected to a corresponding drive circuit 530 provided in this embodiment, and is driven by the drive circuit 530 to achieve engagement and disengagement.

[0076] It should be noted that for details not disclosed in the power module of this embodiment, please refer to the details disclosed in the embodiments of the drive circuit in this specification, which will not be repeated here.

[0077] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art can understand and implement this without any creative effort.

[0078] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application.

Claims

1. A drive circuit of a relay, characterized by comprising: It includes a rectifier unit, a first delay unit, a second delay unit, a first voltage divider unit, a second voltage divider unit, and a drive unit; The positive and negative input terminals of the rectifier unit receive voltage signals. The first delay unit and the first voltage divider unit are connected in series and then in parallel between the first and second terminals of the rectifier unit. The second voltage divider unit and the second delay unit are connected in series and then in parallel between the second and third terminals of the rectifier unit. The first voltage divider unit and the second voltage divider unit are connected together and connected to the second terminal of the rectifier unit. The first and second input terminals of the driving unit are connected to the two ends of the first voltage divider unit, the third input terminal of the driving unit is connected between the second voltage divider unit and the second delay unit, the first and second output terminals of the driving unit are connected to the two ends of the relay, and the second input terminal of the driving unit is grounded.

2. The drive circuit of a relay according to claim 1, characterized by The first delay unit includes a first capacitor, the first voltage divider unit includes a first resistor, the second delay unit includes a second capacitor, and the second voltage divider unit includes a second resistor; One end of the first capacitor is connected to the first end of the rectifier unit, the other end of the first capacitor is connected to one end of the first resistor to form a first node, and the other end of the first resistor is connected to the second end of the rectifier unit. One end of the second resistor is connected to the other end of the first resistor, the other end of the second resistor is connected to one end of the second capacitor to form a second node, and the other end of the second capacitor is connected to the third end of the rectifier unit.

3. The relay driving circuit according to claim 1, characterized in that, The rectifier unit includes a first diode, a second diode, a third diode, a fourth diode, and a third capacitor; The anode of the first diode serves as the positive input terminal of the rectifier unit, the cathode of the first diode is connected to the cathode of the second diode, and the anode of the second diode serves as the negative input terminal of the rectifier unit. The cathode of the third diode is connected to the anode of the first diode, the anode of the third diode is connected to the anode of the fourth diode, and the cathode of the fourth diode is connected to the anode of the second diode. One end of the third capacitor is connected between the first diode and the second diode, and the other end of the third capacitor is connected between the third diode and the fourth diode.

4. The relay driving circuit according to claim 2, characterized in that, The driving circuit further includes a first clamping unit, which includes a fifth diode and a sixth diode. The cathode of the fifth diode is connected to the first node, and the anode of the fifth diode is connected to the second input terminal of the driving unit. The cathode of the sixth diode is connected to the second node, and the anode of the sixth diode is connected to the second input terminal of the driving unit.

5. The relay driving circuit according to claim 4, characterized in that, The first clamping unit includes a seventh diode and an eighth diode; The cathode of the seventh diode is connected to an external power source, and the anode of the seventh diode is connected to the cathode of the fifth diode. The cathode of the eighth diode is connected to an external power source, and the anode of the eighth diode is connected to the cathode of the sixth diode.

6. The driving circuit for the relay according to any one of claims 1 to 5, characterized in that, The driving circuit further includes a second clamping unit, which includes a ninth diode and a tenth diode. The cathode of the ninth diode is connected to an external power supply, the anode of the ninth diode is connected to the cathode of the tenth diode, and the anode of the ninth diode is also connected to the first output terminal of the driving unit, while the anode of the tenth diode is grounded.

7. The driving circuit for the relay according to any one of claims 1 to 5, characterized in that, The driving circuit also includes a third clamping unit, which includes an eleventh diode and a twelfth diode; The cathode of the eleventh diode is connected to an external power supply, the anode of the eleventh diode is connected to the cathode of the twelfth diode, and the anode of the eleventh diode is also connected to the first output terminal of the driving unit, while the anode of the twelfth diode is grounded.

8. The driving circuit for the relay according to any one of claims 1 to 5, characterized in that, The voltage signal is issued by the controller of the charging system.

9. A power module, characterized in that, It includes at least one drive circuit, an AC / DC conversion circuit, and at least one DC / DC conversion circuit as described in any one of claims 1 to 8; The AC / DC conversion circuit and / or the DC / DC conversion circuit are provided with magnetic latching relays, and each magnetic latching relay is connected to one of the drive circuits.

10. The power module according to claim 9, characterized in that, When the AC / DC conversion circuit has the magnetic latching relay, each of the magnetic latching relays is disposed between the input terminal of the AC / DC conversion circuit and the input capacitor. The magnetic latching relays in the AC / DC conversion circuit are used to control the AC / DC conversion circuit to achieve zero power consumption. When the DC / DC converter circuit has the magnetic latching relay, each magnetic latching relay is disposed at the output terminal of the DC / DC converter circuit, and the magnetic latching relay is used in the DC / DC converter circuit to control the series-parallel switching of multiple DC / DC converter circuits.

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