Driving circuit and charging device

Abstract

The utility model relates to a kind of driving circuit and charging equipment, the driving circuit includes: drive module is connected with the coil circuit being equipped with relay coil, for outputing PWM signal to coil circuit in relay attraction stage, and stop outputting PWM signal to coil circuit in relay disconnect stage, PWM signal is used to drive whether relay coil is powered on to make relay attraction;First bleed-off module is connected with the coil circuit, for in relay attraction stage, to the relay coil is discharged;Second bleed-off module is connected with the coil circuit, for in relay disconnect stage, to the relay coil is discharged;Wherein, the conduction voltage drop of first bleed-off module is lower than second bleed-off module. To realize that less heat is generated and relay is quickly disconnected.

Description

Technical Field

[0001] This utility model relates to the field of relay drive technology, and in particular to a drive circuit and charging device. Background Technology

[0002] Currently, AC charging piles are widely used in fixed locations as infrastructure for replenishing electric vehicle power. To ensure the safety and reliability of the charging process, AC charging piles typically have a power relay inside to control the on / off state of the main circuit. A typical driving method is as follows: a switching transistor is connected in series in the relay coil circuit, and the transistor is driven to conduct by a pulse width modulation (PWM) signal, energizing the coil and causing the relay to engage; when it is necessary to disconnect, the PWM signal is stopped, the switching transistor is turned off, and the coil is de-energized.

[0003] To achieve relay disconnection, the relay coil, acting as an inductive load, generates a high reverse induced electromotive force (EMF) due to the sudden current change when the driving switch is turned off. The stored magnetic energy needs to be released; therefore, a discharge circuit is typically connected in parallel across the coil to provide a discharge path for the induced EMF. However, in cases of faults such as leakage, the relay must disconnect extremely quickly to cut off the current. To achieve rapid disconnection, according to the inductor discharge formula, the rate of change of the discharge current is proportional to the reverse voltage. Therefore, a discharge path with a high reverse voltage (i.e., on-state voltage drop) can be set. By increasing the reverse voltage, the consumption of magnetic energy in the coil can be accelerated, thereby achieving rapid relay disconnection.

[0004] However, the above approach, when using PWM to keep the relay engaged, causes the switching transistor to frequently turn on and off. During the turn-off phase of each PWM cycle, the current in the coil is discharged through the aforementioned discharge path. At this time, the set high reverse voltage causes this discharge path to withstand high instantaneous power in each PWM cycle, resulting in large pulse current and power consumption. This energy is ultimately converted into heat, leading to high component temperature rise and reduced system reliability. Utility Model Content

[0005] The main purpose of this utility model is to provide a driving circuit and charging device, which aims to solve the technical problem in the prior art of how to achieve both rapid disconnection of the relay and low temperature when the relay is engaged.

[0006] To achieve the above objectives, this utility model proposes a driving circuit, the driving circuit comprising: A drive module is connected to a coil circuit equipped with a relay coil. It is used to output a PWM signal to the coil circuit during the relay energizing phase and to stop outputting the PWM signal to the coil circuit during the relay de-energizing phase. The PWM signal is used to drive whether the relay coil is energized to make the relay energize. The first discharge module is connected to the coil circuit and is used to discharge the relay coil during the relay energizing phase. The second discharge module is connected to the coil circuit and is used to discharge the relay coil during the relay disconnection phase. The conduction voltage of the first discharge module is lower than that of the second discharge module.

[0007] In one embodiment, the driving circuit further includes: a switching module; The switching module is connected to the first discharge module and the grounding terminal; The switching module is used to connect the first discharge module to the ground terminal during the relay energizing phase, so that the first discharge module discharges the relay coil. The switching module is also used to disconnect the first discharge module from the ground terminal during the relay disconnection phase, so that the second discharge module can discharge the relay coil.

[0008] In one embodiment, the switching module includes: a charge pump unit and a first switching unit; The first switching unit is connected to the first discharge module, the grounding terminal, and the charge pump unit, respectively. The charge pump unit is used to output a first drive signal to the first switch unit during the relay activation phase, so that the first switch unit can connect the first discharge module to the ground terminal. The charge pump unit is also configured to stop outputting the first drive signal to the first switch unit during the relay disconnection phase, so that the first switch unit disconnects the first discharge module from the ground terminal.

[0009] In one embodiment, the driving circuit further includes a power supply module; the coil circuit further includes a second switching unit. The power supply module is connected to the first end of the relay coil, and the second switching unit is connected to the drive module, the second end of the relay coil, the first discharge module, and the second discharge module, respectively. The power supply module is used to provide operating voltage to the relay coil; The drive module is used to output a second drive signal to the second switching unit during the relay energizing phase, so that the second switching unit drives the relay coil to be energized; The drive module is also configured to stop outputting the second drive signal to the second switching unit during the relay disconnection phase, so that the second switching unit drives the relay coil to de-energize.

[0010] In one embodiment, both the power supply module and the drive module are further connected to the charge pump unit; The power supply module is also used to provide the operating voltage to the charge pump unit; The drive module is further configured to output the second drive signal to the charge pump unit during the relay activation phase, so that the charge pump unit outputs the first drive signal; The drive module is also configured to stop outputting the second drive signal to the charge pump unit during the relay disconnection phase, so that the charge pump unit stops outputting the first drive signal.

[0011] In one embodiment, the charge pump unit includes: a first diode, a second diode, a first capacitor, and a second capacitor; The anode of the first diode is connected to the power supply module, the cathode of the first diode is connected to the first terminal of the first capacitor and the anode of the second diode, the second terminal of the first capacitor is connected to the drive module, the cathode of the second diode is connected to the first terminal of the second capacitor and the first switching unit, and the second terminal of the second capacitor is grounded.

[0012] In one embodiment, the switching module further includes: a discharge unit; The discharge unit is connected to the charge pump unit and the first switch unit; The discharge unit is used to discharge the charge pump unit during the relay disconnection phase, so as to stop the charge pump unit from outputting the first drive signal.

[0013] In one embodiment, the discharge unit includes: a first resistor; The first end of the first resistor is connected to the charge pump unit and the first switch unit, and the second end of the first resistor is grounded.

[0014] In one embodiment, the driving circuit further includes: a voltage regulator module; The voltage regulator module is connected to the charge pump unit, the first switching unit, and the grounding terminal; The voltage regulator module is used to transmit the first drive signal to the ground terminal when the voltage value of the first drive signal is higher than the breakdown voltage.

[0015] In addition, to achieve the above objectives, this utility model also proposes a charging device, which includes a relay and a driving circuit as described above.

[0016] This utility model proposes a driving circuit and a charging device. The driving circuit includes: a driving module connected to a coil circuit with a relay coil, used to output a PWM signal to the coil circuit during the relay energizing phase and to stop outputting the PWM signal to the coil circuit during the relay de-energizing phase, wherein the PWM signal is used to drive whether the relay coil is energized to energize the relay; a first discharge module connected to the coil circuit, used to discharge the relay coil during the relay energizing phase; and a second discharge module connected to the coil circuit, used to discharge the relay coil during the relay de-energizing phase; wherein the forward voltage drop of the first discharge module is lower than that of the second discharge module.

[0017] In this invention, two discharge modules with different conduction voltage drops can be provided. During the relay energizing stage, the first discharge module with a lower conduction voltage drop is used to discharge the relay coil. Since the conduction voltage drop is low at this time, less heat is generated. During the relay de-energizing stage, the second discharge module with a higher conduction voltage drop is used to discharge the relay coil. Since the conduction voltage drop is high at this time, the relay can be de-energized quickly. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of this utility model 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 utility model. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0019] Figure 1 This is a circuit schematic diagram of a traditional relay drive circuit. Figure 2 This is a structural block diagram of the first embodiment of the driving circuit proposed in this utility model. Figure 3 This is a structural block diagram of the second embodiment of the driving circuit proposed in this utility model. Figure 4 The circuit schematic diagram is shown in the third embodiment of the driving circuit proposed in this utility model.

[0020] Explanation of icon numbers:

[0021] The realization of the purpose, functional features and advantages of this utility model will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0022] It should be understood that the specific embodiments described herein are merely illustrative of the present invention and are not intended to limit the present invention.

[0023] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0024] It should be noted that all directional indicators (such as up, down, left, right, front, back, etc.) in this utility model embodiment are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicator will also change accordingly.

[0025] Furthermore, the use of terms such as "first" and "second" in this utility model is for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. Additionally, the technical solutions of the various embodiments can be combined with each other, but only on the basis of being achievable by those skilled in the art. When the combination of technical solutions is contradictory or impossible to implement, such a combination of technical solutions should be considered non-existent and not within the scope of protection claimed by this utility model.

[0026] It should be noted that AC charging piles, as an infrastructure for replenishing electric vehicle power, are widely used in fixed locations. To ensure the safety and reliability of the charging process, AC charging piles typically have a power relay inside to control the on / off state of the main circuit. A typical driving method is as follows: a switching transistor is connected in series in the relay coil L1 circuit, and the transistor is driven to conduct by a pulse width modulation (PWM) signal, energizing the coil and causing the relay to engage; when it is necessary to disconnect, the PWM signal is stopped, the switching transistor is turned off, and the coil is de-energized.

[0027] For ease of understanding, please refer to Figure 1 To explain, Figure 1 The circuit schematic of a traditional relay drive circuit, such as Figure 1 As shown, the first terminal of the relay coil L1 can be connected to the power supply VCC, and the second terminal of the relay coil L1 can be connected to the switching transistor and then grounded. The switching transistor can be turned on and off via a PWM signal. When the relay needs to be energized, it receives a PWM signal, the relay coil L1 is energized, and the relay is energized. When the relay needs to be de-energized, it stops receiving PWM signals, the relay coil L1 is de-energized, and the relay is de-energized.

[0028] To achieve relay disconnection, the relay coil L1, acting as an inductive load, generates a high reverse induced electromotive force (EMF) due to the sudden current change at the moment the driving switch transistor is disconnected. The stored magnetic energy needs to be released; therefore, a discharge circuit is typically connected in parallel across the coil to provide a discharge path for the induced EMF. Figure 1 The discharge path can be connected to the second terminal of relay coil L1. When the PWM signal reception stops, the energy in relay coil L1 can be discharged through the discharge path. However, in the event of a fault such as leakage, the relay must disconnect very quickly to cut off the current. To achieve rapid disconnection, according to the inductor discharge formula, the rate of change of discharge current is proportional to the reverse voltage. Therefore, a discharge path with a high reverse voltage (i.e., on-state voltage drop) can be set. By increasing the reverse voltage, the consumption of magnetic energy in the coil can be accelerated, thereby achieving rapid disconnection of the relay.

[0029] However, the above approach, when using PWM to keep the relay engaged, causes the switching transistor to frequently turn on and off. During the turn-off phase of each PWM cycle, the current in the coil is discharged through the aforementioned discharge path. At this time, the set high reverse voltage causes this discharge path to withstand high instantaneous power in each PWM cycle, resulting in large pulse current and power consumption. This energy is ultimately converted into heat, leading to high component temperature rise and reduced system reliability.

[0030] To solve the above-mentioned technical problems, this embodiment provides a driving circuit. In this embodiment, two discharge modules with different conduction voltage drops can be set. During the relay energizing stage, the first discharge module 3 with a lower conduction voltage drop is used to discharge the relay coil L1. Since the conduction voltage drop is low at this time, less heat is generated. During the relay de-energizing stage, the second discharge module 4 with a higher conduction voltage drop is used to discharge the relay coil L1. Since the conduction voltage drop is high at this time, the relay can be de-energized quickly.

[0031] For ease of understanding, the following is combined with Figures 2 to 4 The driving circuit provided in the embodiments of this application will be described in detail.

[0032] Reference Figure 2 , Figure 2This is a structural block diagram of the first embodiment of the driving circuit proposed in this utility model.

[0033] like Figure 2 As shown, in this embodiment, the driving circuit may include: The drive module 1 is connected to the coil circuit 2, which has a relay coil L1, and is used to output a PWM signal to the coil circuit 2 during the relay energizing phase and to stop outputting the PWM signal to the coil circuit 2 during the relay de-energizing phase. The PWM signal is used to drive whether the relay coil L1 is energized to make the relay energize.

[0034] It should be noted that the aforementioned drive module 1 can be a module for generating PWM signals to control whether the relay coil L1 is energized. The aforementioned coil circuit 2 can be an electrical circuit formed by the relay coil L1. The coil circuit 2 can also contain a switching transistor to receive PWM signals and control whether the relay coil L1 is energized.

[0035] It should also be noted that the relay engaging stage described above can be the stage where the relay contacts are closed, during which the relay coil L1 is energized and the relay engages. The relay disengaging stage described above can be the stage where the relay contacts are open, during which the relay coil L1 is de-energized and the relay disengages.

[0036] Understandably, in this embodiment, the drive module 1 can output a PWM signal to enter the relay engaging stage, and stop outputting the PWM signal to enter the relay disengaging stage.

[0037] To achieve low heat generation in the relay coil L1 during the relay engagement phase and rapid disconnection during the relay disengagement phase, as follows: Figure 2 As shown, in this embodiment, the first discharge module 3 is connected to the coil circuit 2 and is used to discharge the relay coil L1 during the relay energizing stage. The second discharge module 4 is connected to the coil circuit 2 and is used to discharge the relay coil L1 during the relay disconnection phase. The conduction voltage of the first discharge module 3 is lower than that of the second discharge module 4.

[0038] Understandably, the aforementioned first discharge module 3 can serve as an energy release path for the relay coil L1 when the current is cut off. In this embodiment, since the relay coil L1 stores magnetic energy when energized, when the drive current is suddenly cut off (e.g., the switch is turned off), according to Lenz's law, the relay coil L1 will generate a high reverse induced electromotive force (voltage) in the opposite direction in an attempt to maintain the original current. If this high-voltage spike does not have a suitable discharge path, it will break down the switch or other components, causing damage. Therefore, in this embodiment, the aforementioned first discharge module 3 and second discharge module 4 can be configured to dissipate this magnetic energy.

[0039] It is also understood that in this embodiment, the on-state voltage drop of the first discharge module 3 is lower than that of the second discharge module 4. Therefore, in actual use, during the relay's activation phase, the PWM signal causes the switching transistor in the coil circuit 2 to switch on and off at high frequency. At the moment of off in each PWM cycle, the coil generates an induced electromotive force. At this time, the first discharge module 3 can be controlled to be in the on state, and the magnetic energy of the coil is mainly released through this low on-state voltage drop path. Due to the lower voltage drop, under the same discharge current, this path consumes less power, thus reducing heat generation and meeting the low power consumption and low heat generation requirements of the relay during long-term operation.

[0040] During the relay disconnection phase, drive module 1 stops the PWM signal, and the first discharge module 3 is also turned off. The induced electromotive force generated by the coil is forced to be discharged through the second discharge module 4. Because the conduction voltage drop of the second discharge module 4 is high, the reverse voltage applied to the relay coil L1 (i.e., the conduction voltage drop of the second discharge module 4) becomes higher, thus increasing the rate of decrease of the coil current, thereby achieving rapid relay disconnection, which is beneficial for arc extinguishing and improving lifespan.

[0041] In this embodiment, since two discharge modules with different conduction voltage drops can be set, during the relay energizing stage, the first discharge module 3 with a lower conduction voltage drop is used to discharge the relay coil L1. Since the conduction voltage drop is low at this time, less heat is generated. During the relay de-energizing stage, the second discharge module 4 with a higher conduction voltage drop is used to discharge the relay coil L1. Since the conduction voltage drop is high at this time, the relay can be de-energized quickly.

[0042] Furthermore, in order to achieve discharge through the first discharge module 3 during the relay engagement phase, such as... Figure 2 As shown, in this embodiment, the driving circuit further includes: a switching module 5; The switching module 5 is connected to the first discharge module 3 and the grounding terminal; The switching module 5 is used to connect the first discharge module 3 to the ground terminal during the relay energizing phase, so that the first discharge module 3 discharges the relay coil L1. The switching module 5 is also used to disconnect the first discharge module 3 from the ground terminal during the relay disconnection phase, so that the second discharge module 4 discharges the relay coil L1.

[0043] It should be noted that the aforementioned switching module 5 can be any module with on / off switching function. It can automatically connect or disconnect the grounding path of the first discharge module 3 according to the working stage of the relay (engaged or disconnected), thereby determining which discharge module works.

[0044] It should also be noted that the above-mentioned grounding terminal (i.e. Figure 2 GND1 can refer to the reference zero potential point of the circuit. In this embodiment, it can be the common terminal of the circuit that the first discharge module 3 needs to form when it completes current discharge. In this embodiment, the first end of the relay coil L1 can be connected to the ground terminal, the second end of the relay coil L1 is connected to the first discharge module 3 and the second discharge module 4, and the first switch unit 52 and the first discharge module 3 are also connected to the ground terminal.

[0045] In practical use, when the relay is in the energizing phase, the switching module 5 connects the end of the first discharge module 3 to the ground terminal, thus forming a complete and usable current path for the first discharge module 3. At the moment of turn-off in each PWM cycle, the induced current generated by the relay coil L1 will choose the path with the lowest impedance and naturally discharge through this grounded first discharge module 3.

[0046] When the relay is in the off-state phase, the switching module 5 disconnects the first discharge module 3 from the grounding terminal. The first discharge module 3 immediately fails due to the loss of its grounding circuit and can no longer discharge energy. At this time, the high-voltage induced electromotive force generated by the relay coil L1 at the moment of turn-off detects that the low-impedance first discharge module 3 has been disconnected, and then switches to the second discharge module 4, through which energy is discharged.

[0047] Furthermore, in order to achieve the switching function, continue as follows: Figure 2 As shown, in this embodiment, the switching module 5 includes: a charge pump unit 51 and a first switching unit 52; The first switch unit 52 is connected to the first discharge module 3, the grounding terminal, and the charge pump unit 51, respectively. The charge pump unit 51 is used to output a first drive signal to the first switch unit 52 during the relay energizing phase, so that the first switch unit 52 connects the first discharge module 3 to the ground terminal. The charge pump unit 51 is also used to stop outputting the first drive signal to the first switch unit 52 during the relay disconnection phase, so that the first switch unit 52 disconnects the first discharge module 3 from the ground terminal.

[0048] It should be understood that the charge pump unit 51 described above can be any unit used to provide voltage. In this embodiment, it can be used to output a first drive signal to drive the first switching unit 52 to turn on or off. The first switching unit 52 described above can be any unit with on / off function, such as a switching transistor, etc., and this embodiment does not limit it.

[0049] In actual use, when entering the engagement phase, the charge pump unit 51 is activated to generate a first drive signal, which is applied to the first switch unit 52, thus connecting the first discharge module 3 to the ground terminal. When entering the disengagement phase, the charge pump unit 51 stops working, and no first drive signal is output; the first switch unit 52 then disconnects the connection between the first discharge module 3 and the ground terminal.

[0050] Furthermore, in order to achieve the gain / loss control of the relay coil L1, continue as follows: Figure 2 As shown, in this embodiment, the driving circuit further includes a power supply module 6; the coil circuit 2 further includes a second switching unit 21. The power supply module 6 is connected to the first end of the relay coil L1, and the second switch unit 21 is connected to the drive module 1, the second end of the relay coil L1, the first discharge module 3 and the second discharge module 4 respectively. The power supply module 6 is used to provide operating voltage to the relay coil L1; The drive module 1 is used to output a second drive signal to the second switch unit 21 during the relay energizing phase, so that the second switch unit 21 drives the relay coil L1 to be energized. The drive module 1 is also used to stop outputting the second drive signal to the second switch unit 21 during the relay disconnection phase, so that the second switch unit 21 drives the relay coil L1 to de-energize.

[0051] It should be noted that the power supply module 6 mentioned above can be any module used to power the relay coil L1, such as a DC regulated power supply, etc., and this embodiment does not impose any restrictions on it. The drive module 1 mentioned above can be any module that drives the second switching unit 21 to switch on and off, such as a PWM signal generator V2, etc., and this embodiment does not impose any restrictions on it.

[0052] It should also be noted that one end of the second switching unit 21 can be connected to the second end of the relay coil L1, while the other end of the second switching unit 21 can be grounded.

[0053] Then, when drive module 1 outputs the second drive signal (i.e. Figure 2 When the PWM signal is applied, the second switching unit 21 turns on the circuit between the relay coil L1 and the ground terminal, and then the relay coil L1 is energized by the working voltage provided by the power supply module 6 and enters the relay energizing stage. When the drive module 1 stops outputting the second drive signal, the second switching unit 21 disconnects the circuit between the relay coil L1 and the ground terminal, and the relay coil L1 is de-energized and enters the relay de-energizing stage.

[0054] In this embodiment, since two discharge modules with different conduction voltage drops can be set, during the relay energizing stage, the first discharge module 3 with a lower conduction voltage drop is used to discharge the relay coil L1. Since the conduction voltage drop is low at this time, less heat is generated. During the relay de-energizing stage, the second discharge module 4 with a higher conduction voltage drop is used to discharge the relay coil L1. Since the conduction voltage drop is high at this time, the relay can be de-energized quickly.

[0055] Reference Figure 3 , Figure 3 This is a structural block diagram of the second embodiment of the driving circuit proposed in this utility model.

[0056] Based on the first embodiment described above, a second embodiment of the driving circuit of this utility model is proposed, as follows: Figure 3 As shown, considering that the charge pump unit 51 needs to be powered to output the first drive signal, and in order to ensure synchronization, the first drive signal and the second drive signal need to be at the same frequency, that is, the first switch unit 52 and the second switch unit 21 are turned on and off at the same time. Therefore, in order to save costs and facilitate control, in this embodiment, the power supply module 6 and the drive module 1 are also connected to the charge pump unit 51. The power supply module 6 is also used to provide the operating voltage to the charge pump unit 51; The drive module 1 is also used to output the second drive signal to the charge pump unit 51 during the relay energizing phase, so that the charge pump unit 51 outputs the first drive signal; The drive module 1 is also used to stop outputting the second drive signal to the charge pump unit 51 during the relay disconnection phase, so that the charge pump unit 51 stops outputting the first drive signal.

[0057] It should be noted that, as Figure 3As shown, in this embodiment, the power supply module 6 can also be directly connected to the charge pump unit 51 to provide the operating voltage for the charge pump unit 51. Alternatively, the drive module 1 can be directly connected to the charge pump unit 51 to transmit the generated PWM signal as the aforementioned second drive signal to the charge pump unit 51, serving as the clock input for the charge pump unit 51.

[0058] In practical use, during the relay activation phase, the drive module 1 outputs a second drive signal to the charge pump unit 51. Once the charge pump unit 51 receives this signal, it uses it as a clock source and generates a first drive signal using the operating voltage provided by the power supply module 6, thereby turning on the first switch unit 52. At this time, since the second drive signal can also be input to the second switch unit 21, it can be ensured that the first switch unit 52 and the second switch unit 21 are turned on simultaneously.

[0059] During the relay disconnection phase: Drive module 1 stops outputting the second drive signal. Charge pump unit 51 immediately stops working, and the first drive signal disappears rapidly, causing the first switch unit 52 to turn off. At this time, since the second drive signal can still be input to the second switch unit 21, it can be ensured that the first switch unit 52 and the second switch unit 21 disconnect simultaneously.

[0060] Furthermore, considering that the energy stored in the charge pump unit 51 needs to be released when the first discharge module 3 is no longer needed, therefore, the process continues as follows... Figure 3 As shown, in this embodiment, the switching module 5 further includes a discharge unit 53; The discharge unit 53 is connected to the charge pump unit 51 and the first switch unit 52; The discharge unit 53 is used to discharge the charge pump unit 51 during the relay disconnection phase, so that the charge pump unit 51 stops outputting the first drive signal.

[0061] It should be noted that the above-mentioned discharge unit 53 can be any unit used for discharge, such as a resistor, and this embodiment does not limit it.

[0062] In practical use, the discharge unit 53 can be directly connected between the output node of the charge pump and ground. When the charge pump unit 51 stops receiving the second drive signal, it can release electrical energy through the discharge unit 53, thereby causing the charge pump unit 51 to stop outputting the first drive signal.

[0063] Furthermore, to prevent the first drive signal output by the charge pump unit 51 from being too high and causing the first switching unit 52 to break down, the following steps are continued... Figure 3 As shown, the driving circuit in this embodiment further includes: a voltage regulator module 7; The voltage regulator module 7 is connected to the charge pump unit 51, the first switch unit 52, and the grounding terminal; The voltage regulator module 7 is used to transmit the first drive signal to the ground terminal when the voltage value of the first drive signal is higher than the breakdown voltage.

[0064] It is understood that the aforementioned voltage regulator module 7 can be any module with voltage clamping function, such as a Zener diode, and this embodiment does not impose any restrictions on it. The aforementioned breakdown voltage can be the voltage required to break down the voltage regulator module 7, and can be specifically set according to the safety voltage setting of the first switching module; this embodiment does not impose any restrictions on it.

[0065] In practical use, under normal operating conditions, the voltage of the first drive signal output by the charge pump unit 51 is designed to be lower than the breakdown voltage of the voltage regulator module 7. At this time, the voltage regulator module 7 presents high impedance, which has no impact on the circuit operation. When an abnormality occurs (such as charge pump misalignment, voltage spikes, etc.), the voltage of the first drive signal may be higher than the breakdown voltage, thereby causing the voltage regulator module 7 to break down and transmit the first drive signal to the ground terminal, thus improving the safety of the circuit.

[0066] Reference Figure 4 , Figure 4 The circuit schematic diagram is shown in the third embodiment of the driving circuit proposed in this utility model.

[0067] Based on the above embodiments, a third embodiment of the driving circuit of this utility model is proposed. For example... Figure 4 As shown, in this embodiment, the power supply module 6 may include: a power supply V1 and a second resistor R2; The positive terminal of the power supply V1 can be connected to the first end of the second resistor R2. The second end of the second resistor R2 is connected to the first end of the relay coil L1, the second discharge module 4, the first switch unit 52, and the charge pump unit 51. The negative terminal of the power supply V1 is grounded.

[0068] It should be noted that the power supply V1 mentioned above can be any DC regulated power supply, which can be used to provide the working voltage (i.e. Figure 4 (VCC). The second resistor R2 mentioned above can be a resistor used for current limiting.

[0069] In actual use, the power supply V1 can provide the working voltage to the relay coil L1 and the charge pump unit 51 through the second resistor R2.

[0070] Furthermore, the aforementioned driving module 1 may include: a PWM signal generator V2; the driving circuit may also include: a third resistor R3; The positive terminal of the PWM signal generator V2 is connected to the charge pump unit 51 and the first end of the third resistor R3. The second end of the third resistor R3 is connected to the second switch unit 21. The negative terminal of the PWM signal generator V2 is grounded.

[0071] It should also be noted that the PWM signal generator V2 mentioned above can be any device used to generate the PWM signal (i.e., the second drive signal mentioned above). The third resistor R3 mentioned above can be used to increase loop damping.

[0072] In practical use, the PWM signal generator V2 can output a second drive signal (i.e. Figure 4 The PWM signal is transmitted to the second switching unit 21 to turn it on, and the second drive signal is output to the charge pump unit 51, so that the charge pump unit 51 outputs the first drive signal.

[0073] Furthermore, the second switching unit 21 may include: a second switching transistor M2; The gate of the second switching unit 21 is connected to the second end of the third resistor R3, the drain of the second switching transistor M2 is connected to the second end of the relay coil L1, the first discharge module 3 and the second discharge module 4, and the source of the second switching transistor M2 is grounded.

[0074] It is understood that the second switch M2 can be any controllable switch. In this embodiment, a metal-oxide-semiconductor field-effect transistor can be used for illustration, specifically an N-channel MOS transistor.

[0075] In practical use, the PWM signal generator V2 first outputs a long high-level second drive signal to the second switch M2, turning on the second switch M2 and entering the relay energizing stage. Then, it outputs alternating high and low-level second drive signals, causing the second switch M2 to turn on and off at high frequency. However, due to the presence of the first discharge module 3, the relay coil L1 remains energized. When the gate of the second switch M2 no longer receives the second drive signal, it turns off, entering the relay de-energizing stage.

[0076] Furthermore, the aforementioned first discharge module 3 includes: a third diode D3; the driving circuit also includes: a third capacitor C3; The anode of the third diode D3 is connected to the second terminal of the first relay coil L1 and the second discharge module 4. The cathode of the third diode D3 is connected to the first switching transistor M1. The first switching unit 52 is also connected to the second discharge module 4 and the first terminal of the relay coil L1. The first terminal of the relay coil L1 is also connected to the first terminal of the third capacitor C3. The second terminal of the third capacitor C3 is connected to the ground terminal.

[0077] It is also understood that the third diode D3 mentioned above can be any diode, such as a Zener diode, etc. This embodiment does not limit this.

[0078] In practical use, when the first switching unit 52 connects the third diode D3 to the ground terminal (i.e., Figure 4 After GND1 is turned on, during the low-level phase of the PWM signal, the relay coil L1 begins to release energy. The current output from the relay coil L1 passes through the third diode D3, the first switching unit 52, and then to the third capacitor C3, thus forming a circuit with the ground terminal to discharge the relay coil L1.

[0079] When the first switching unit 52 disconnects the third diode D3 from the ground terminal, the second discharge module 4 is connected to the ground terminal. Then, when the second switching transistor M2 does not receive the PWM signal, the relay coil L1 releases energy. The current output from the relay coil L1 passes through the second discharge module 4 to the third capacitor C3, thus forming a circuit with the ground terminal to realize the discharge of the relay coil L1.

[0080] Furthermore, the aforementioned second discharge module 4 includes: a fourth diode D4 and a fifth diode D5; The anode of the fourth diode D4 is connected to the relay coil L1 and the anode of the third diode D3. The cathode of the fourth diode D4 is connected to the anode of the fifth diode D5. The cathode of the fifth diode D5 is connected to the first switch unit 52, the relay coil L1 and the first terminal of the third capacitor C3.

[0081] It should be understood that the fourth diode D4 can be a Zener diode or a transient voltage suppressor diode, and the fifth diode D5 can be a Schottky diode or a fast recovery diode. In this embodiment, the fourth diode D4 is a Zener diode, and the fifth diode D5 is a Schottky diode. It should also be understood that, because the fifth diode D5 is connected in reverse, the forward voltage drop formed by connecting the fourth diode D4 and the fifth diode D5 in series is higher than that of the third diode D3.

[0082] In actual use, when the relay is in the off stage, the relay current is forced to flow through the fourth diode D4 and break down the fifth diode D5, thus being transmitted to the third capacitor C3 to achieve discharge.

[0083] Furthermore, in order to output the first drive signal, continue as follows: Figure 4 As shown, the charge pump unit 51 includes: a first diode D1, a second diode D2, a first capacitor C1, and a second capacitor C2; The anode of the first diode D1 is connected to the power supply module 6, the cathode of the first diode D1 is connected to the first terminal of the first capacitor C1 and the anode of the second diode D2, the second terminal of the first capacitor C1 is connected to the drive module 1, the cathode of the second diode D2 is connected to the first terminal of the second capacitor C2 and the first switching unit 52, and the second terminal of the second capacitor C2 is grounded.

[0084] It should be noted that both the first diode D1 and the second diode D2 can be Schottky diodes or similar devices; this embodiment does not impose any restrictions on this. Both the first diode D1 and the second diode D2 can be used to prevent backflow. The first capacitor C1 and the second capacitor C2 can be used for energy storage.

[0085] In practical use, when the operating voltage (i.e.) is received Figure 4 (VCC) and the second drive signal (i.e. Figure 4 When the second drive signal is in the low-level stage during PWM (PWM), the drive module 1 outputs a low level (0V) to the second terminal of the first capacitor C1. Since the voltage across the capacitor cannot change abruptly, the voltage at the first terminal of the first capacitor C1 is also pulled low, forming a negative voltage. This negative voltage causes the first diode D1 to be forward biased and conduct. Current flows out from the power supply module 6, through the first diode D1, and charges the first capacitor C1. At this time, the first capacitor C1 is charged to approximately VCC-Vf(D1) (Vf is the diode voltage drop). At this time, the anode of the second diode D2 is at a low voltage, and the cathode is the voltage of the second capacitor C2 (initially 0V or negative voltage). Therefore, the second diode D2 is in a reverse bias cutoff state to prevent charge backflow.

[0086] If the second drive signal is at a high level at this time, drive module 1 outputs a high level (e.g., 3.3V) to the second terminal of the first capacitor C1. Since the voltage across the capacitor cannot change abruptly, the voltage at the first terminal of the first capacitor C1 is also raised by about 3.3V. Its voltage becomes: (VCC-Vf(D1))+3.3V. This instantaneous high voltage causes the first diode D1 to be reverse-biased and cut off because the cathode voltage is higher than the anode, preventing charge from flowing back into the power supply. At the same time, this high voltage causes the second diode D2 to be forward-biased and conduct. Thus, the charge stored on the first capacitor C1 is transferred to the second capacitor C2 through the conducting second diode D2. Since the cathode of the second capacitor C2 is grounded, this charge transfer process will accumulate a negative voltage at the first terminal (i.e., the output terminal) of the second capacitor C2. After multiple PWM cycles, the charge is continuously "pumped" onto the second capacitor C2, thereby establishing and maintaining a stable negative voltage -Vout across its terminals. This -Vout can then be the aforementioned first drive signal, turning on the first switching unit 52.

[0087] Furthermore, the aforementioned first switching unit 52 includes: a first switching transistor M1; The gate of the first switching transistor M1 is connected to the cathode of the second diode D2, the drain of the first switching transistor M1 is connected to the cathode of the third diode D3, and the source of the first switching transistor M1 is connected to the anode of the fifth diode D5.

[0088] It is understood that the first switching transistor M1 can be any controllable switching transistor. In this embodiment, a metal-oxide-semiconductor field-effect transistor can be used for illustration, specifically an N-channel MOS transistor.

[0089] In practical use, during the relay activation phase (requiring the first discharge module 3 to operate), the charge pump unit 51 operates, outputting a negative voltage (first drive signal) to the gate of the first switching transistor M1. At this time, the source potential of the first switching transistor M1 is close to ground level (0V). Therefore, since the gate voltage is negative, the source voltage is approximately equal to the diode voltage drop (approximately 0.7V), thus enabling the first switching transistor M1 to conduct fully. Connecting the first discharge module 3 (third diode D3) to the reference point of the second discharge module 4 (anode of the fifth diode D5) provides a complete grounding loop for the first discharge module 3, allowing it to begin operation.

[0090] During the relay disconnection phase (requiring the first discharge module 3 to stop operating), the charge pump unit 51 stops working, and the gate voltage of the first switching transistor M1 is released through the discharge resistor, returning to 0V. At this time, the first switching transistor M1 is quickly turned off. After being turned off, the current path of the first discharge module 3 is cut off. The induced electromotive force generated by the relay coil L1 can no longer be released through the low-loss first discharge module 3, and can only be rapidly discharged through the high reverse voltage second discharge module 4.

[0091] Furthermore, the discharge unit 53 includes: a first resistor R1; The first end of the first resistor R1 is connected to the charge pump unit 51 and the first switch unit 52, and the second end of the first resistor R1 is grounded.

[0092] It should be noted that the first resistor R1 mentioned above can be a resistor used to write the energy of the charge pump unit 51.

[0093] In actual use, when the charge pump unit 51 stops receiving the second drive signal, the energy in the charge pump unit 51 can be discharged through the first resistor R1 to form a circuit.

[0094] Furthermore, the aforementioned voltage regulator module 7 includes: a sixth diode D6; The anode of the sixth diode D6 is connected to the source of the first switching transistor M1, and the cathode of the sixth diode D6 is connected to the gate of the first switching transistor M1.

[0095] It is understood that the aforementioned sixth diode D6 can be any diode used for voltage regulation and protection; this embodiment uses a Zener diode for illustration. It should also be noted that in this embodiment, the breakdown voltage of the sixth diode D6 can be greater than the gate-source voltage difference of the first switching transistor M1. Therefore, in actual use, when the first drive signal is higher than this breakdown voltage, the sixth diode D6 breaks down in reverse, and the first drive signal can be output to the third capacitor C3 and then grounded, thus providing protection.

[0096] In addition, to achieve the above objectives, this embodiment also provides a charging device, which includes a relay and a driving circuit as described above.

[0097] The specific structure of the driving circuit can be referred to in the above embodiments. Since this charging device adopts all the technical solutions of all the above embodiments, it has at least all the beneficial effects brought about by the technical solutions of the above embodiments, and will not be described in detail here.

[0098] The above are merely preferred embodiments of this utility model and do not limit the scope of protection of this utility model. Any equivalent structural or procedural transformations made based on the description and drawings of this utility model, or direct or indirect applications in other related technical fields, are similarly included within the scope of protection of this utility model.

Claims

1. A driving circuit, characterized in that, The driving circuit includes: A drive module is connected to a coil circuit equipped with a relay coil. It is used to output a PWM signal to the coil circuit during the relay energizing phase and to stop outputting the PWM signal to the coil circuit during the relay de-energizing phase. The PWM signal is used to drive whether the relay coil is energized to make the relay energize. The first discharge module is connected to the coil circuit and is used to discharge the relay coil during the relay energizing phase. The second discharge module is connected to the coil circuit and is used to discharge the relay coil during the relay disconnection phase. The conduction voltage of the first discharge module is lower than that of the second discharge module.

2. The driving circuit as described in claim 1, characterized in that, The driving circuit further includes: a switching module; The switching module is connected to the first discharge module and the grounding terminal; The switching module is used to connect the first discharge module to the ground terminal during the relay energizing phase, so that the first discharge module discharges the relay coil. The switching module is also used to disconnect the first discharge module from the ground terminal during the relay disconnection phase, so that the second discharge module can discharge the relay coil.

3. The driving circuit as described in claim 2, characterized in that, The switching module includes: a charge pump unit and a first switching unit; The first switching unit is connected to the first discharge module, the grounding terminal, and the charge pump unit, respectively. The charge pump unit is used to output a first drive signal to the first switch unit during the relay activation phase, so that the first switch unit can connect the first discharge module to the ground terminal. The charge pump unit is also configured to stop outputting the first drive signal to the first switch unit during the relay disconnection phase, so that the first switch unit disconnects the first discharge module from the ground terminal.

4. The driving circuit as described in claim 3, characterized in that, The driving circuit further includes a power supply module; the coil circuit further includes a second switching unit. The power supply module is connected to the first end of the relay coil, and the second switching unit is connected to the drive module, the second end of the relay coil, the first discharge module, and the second discharge module, respectively. The power supply module is used to provide operating voltage to the relay coil; The drive module is used to output a second drive signal to the second switching unit during the relay energizing phase, so that the second switching unit drives the relay coil to be energized; The drive module is also configured to stop outputting the second drive signal to the second switching unit during the relay disconnection phase, so that the second switching unit drives the relay coil to de-energize.

5. The driving circuit as described in claim 4, characterized in that, Both the power supply module and the drive module are connected to the charge pump unit. The power supply module is also used to provide the operating voltage to the charge pump unit; The drive module is further configured to output the second drive signal to the charge pump unit during the relay activation phase, so that the charge pump unit outputs the first drive signal; The drive module is also configured to stop outputting the second drive signal to the charge pump unit during the relay disconnection phase, so that the charge pump unit stops outputting the first drive signal.

6. The driving circuit as described in claim 5, characterized in that, The charge pump unit includes: a first diode, a second diode, a first capacitor, and a second capacitor; The anode of the first diode is connected to the power supply module, the cathode of the first diode is connected to the first terminal of the first capacitor and the anode of the second diode, the second terminal of the first capacitor is connected to the drive module, the cathode of the second diode is connected to the first terminal of the second capacitor and the first switching unit, and the second terminal of the second capacitor is grounded.

7. The driving circuit as described in claim 3, characterized in that, The switching module further includes: a discharge unit; The discharge unit is connected to the charge pump unit and the first switch unit; The discharge unit is used to discharge the charge pump unit during the relay disconnection phase, so as to stop the charge pump unit from outputting the first drive signal.

8. The driving circuit as described in claim 7, characterized in that, The discharge unit includes: a first resistor; The first end of the first resistor is connected to the charge pump unit and the first switch unit, and the second end of the first resistor is grounded.

9. The driving circuit as described in claim 3, characterized in that, The driving circuit also includes: a voltage regulator module; The voltage regulator module is connected to the charge pump unit, the first switching unit, and the grounding terminal; The voltage regulator module is used to transmit the first drive signal to the ground terminal when the voltage value of the first drive signal is higher than the breakdown voltage.

10. A charging device, characterized in that, The charging device includes a relay and a drive circuit as described in any one of claims 1 to 9.

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