A transformer isolation driving circuit for an on-board power supply

Abstract

The utility model relates to the field of power electronics, and specifically provides a transformer isolation drive circuit of vehicle-mounted power supply, including isolation transformer, chip drive module, two groups of primary drive module, two groups of secondary drive module, the chip drive module adopts double -channel drive chip, single group primary drive module includes first resistance and first series diode, single group secondary drive module includes MOS pipe, second resistance and second series diode, drive resistance, the application creates double -channel drive, can be applicable to half -bridge, full -bridge topological structure, and good applicability, high practicality. The circuit overall structure is simple, and from the economic angle, isolation transformer is easy to wind, can adjust the turns ratio of transformer primary and secondary according to actual drive voltage, is flexible both in cost and low, has good market application value.

Description

Technical Field

[0001] This utility model relates to the field of power electronics technology, specifically to a transformer isolation drive circuit for vehicle power supplies. Background Technology

[0002] With the development of automotive power supplies, power has increased from tens of watts to tens of kilowatts, and the power supply topologies have also diversified. However, the driving capability of PWM chips is limited. For low-power power supplies, the switching transistors can be directly driven by the chip, but for high-power power supplies, the switching transistors cannot be directly driven by the chip. In addition, in high-current or high-frequency applications, direct chip driving is easily subject to signal interference. Utility Model Content

[0003] In view of the shortcomings of the prior art described above, the purpose of this utility model is to provide a transformer isolation drive circuit for vehicle power supply. By setting a primary drive module and a secondary drive module in conjunction with an isolation transformer, the drive signal of the chip is transmitted to the external switching transistor. The separate drive of the primary drive module and the secondary drive module not only ensures the driving capability of the circuit, but also avoids the problem of signal interference. This is used to solve the problem that direct chip drive is easily affected by signal interference in the prior art.

[0004] To achieve the above and other related objectives, this utility model provides a transformer isolation drive circuit for vehicle power supply, which employs an isolation transformer with one primary winding and two secondary windings.

[0005] The circuit includes:

[0006] The chip driver module uses a dual-channel driver chip U1, and the input terminal of the dual-channel driver chip U1 is used to receive external PWM signals.

[0007] Two sets of primary drive modules, each set of primary drive modules includes a first resistor and a first series diode. The first resistor is connected in series between the connection terminal of the primary winding of the isolation transformer and the output terminal of the dual-channel drive chip U1. The common connection point of the first series diode is connected in parallel between the connection terminal of the primary winding of the isolation transformer and the first resistor.

[0008] Two sets of secondary drive modules are provided. Each set of secondary drive modules includes a MOSFET, a second resistor, a second series diode, and a drive resistor. One connection terminal of the secondary winding of the isolation transformer is connected to both the second resistor and the drain of the MOSFET. The other end of the second resistor is connected to the gate of an external switch. The common junction of the second series diode is connected to the drive resistor. The other connection terminal of the secondary winding of the isolation transformer is connected between the common junction of the second series diode and the drive resistor. The other end of the drive resistor is connected to the gate of the MOSFET. The input terminal of the second series diode is connected to the source of the MOSFET, and the output terminal is connected to the source of the external switch.

[0009] In one embodiment of the present invention, one of the primary drive modules further includes an electrolytic capacitor connected between the primary winding of the isolation transformer and the first resistor.

[0010] In one embodiment of the present invention, the dual-channel driver chip U1 includes channel A and channel B, each channel having an independent enable control terminal, input terminal and output terminal.

[0011] In one embodiment of this utility model, the enable control terminals of both channel A and channel B are connected to the power supply pins of the dual-channel driver chip U1 to ensure that channels A and B are always allowed to be used.

[0012] In one embodiment of the present invention, a third resistor is connected in series at both the input and output terminals of the second series diode.

[0013] In one embodiment of this utility model, a compensation is connected in series between the output terminal of the second series diode and the source of the external switching transistor.

[0014] In one embodiment of this utility model, the MOS transistor is an N-channel transistor.

[0015] In one embodiment of the present invention, the first series diode and the second series diode have the same structure, both consisting of two diodes connected in series, and the connection point between the two diodes is a common connection point.

[0016] As described above, the transformer isolation drive circuit of the vehicle power supply of this utility model has the following beneficial effects:

[0017] 1. This invention creates a primary drive module and a secondary drive module in conjunction with an isolation transformer to transmit the chip's drive signal to an external switching transistor. The separate drive of the primary drive module and the secondary drive module ensures the circuit's drive capability while avoiding signal interference.

[0018] 2. This invention creates a first series diode in the primary drive module and a second series diode in the secondary drive module. The first series diode can achieve voltage clamping, limiting the voltage in the circuit to a safe range, thereby protecting the components in the circuit from overvoltage damage. The second series diode can work with the MOSFET to form a discharge circuit, which can quickly discharge the circuit when the drive stops, thereby quickly shutting down the circuit.

[0019] 3. This invention employs a dual-channel driver chip, with both the primary and secondary driver modules having two sets of components to achieve dual-channel drive. It is applicable to half-bridge and full-bridge topologies, offering good applicability and high practicality. The overall circuit structure is simple, and from an economic perspective, the isolation transformer is easy to wind. The turns ratio of the primary and secondary windings can be adjusted according to the actual drive voltage, making it flexible, low-cost, and possessing significant market application value. Attached Figure Description

[0020] Figure 1 The circuit diagram shown is of the transformer isolation drive circuit of the vehicle power supply disclosed in Example 1.

[0021] Figure 2 The circuit diagram shown is of the transformer isolation drive circuit of the vehicle power supply disclosed in Example 3. Detailed Implementation

[0022] The following specific embodiments illustrate the implementation of this utility model. Those skilled in the art can easily understand other advantages and effects of this utility model from the content disclosed in this specification.

[0023] Example 1, please refer to Figure 1 This embodiment provides a transformer isolation drive circuit for vehicle power supply, which uses an isolation transformer 44 with one primary winding and two secondary windings. The circuit includes a chip drive module 1, two sets of primary drive modules 2, and two sets of secondary drive modules 3.

[0024] The chip driver module 1 uses a dual-channel driver chip U1 with model number NSD1025-DSPR. The dual-channel driver chip U1 includes channel A and channel B. Each channel has an independent enable control terminal, input terminal and output terminal. The input terminals of both channel A and channel B are used to receive external PWM signals. The enable control terminals of both channel A and channel B are connected to the power supply pin of the dual-channel driver chip U1 to ensure that channels A and B are always allowed to be used.

[0025] The primary drive module 2 of the single group includes a first resistor 5 and a first series diode 6. The first resistor 5 is connected in series between the connection terminal of the primary winding of the isolation transformer 4 and the output terminal of the dual-channel drive chip U1. The common junction of the first series diode 6 is connected in parallel between the connection terminal of the primary winding of the isolation transformer 4 and the first resistor 5. The input terminal of the first series diode 6 is grounded and the output terminal is connected to VDD, which is used to achieve voltage clamping, so that the voltage in the circuit is limited to a safe range, thereby protecting the components in the circuit from overvoltage damage.

[0026] One of the primary drive modules also includes an electrolytic capacitor 7, which is connected between the primary winding of the isolation transformer 4 and the first resistor 5. The electrolytic capacitor 7 can store energy. When the input of the circuit is suddenly de-energized, the energy stored in the electrolytic capacitor 7 can continue to maintain the output voltage, which is beneficial for data preservation after the electronic product is suddenly de-energized.

[0027] Each secondary drive module 3 includes a MOSFET 8, a second resistor 9, a second series diode 10, and a drive resistor 11. The MOSFET 8 is an N-channel transistor. One terminal of the secondary winding of the isolation transformer 4 is connected to both the second resistor 9 and the drain of the MOSFET 8, while the other terminal of the second resistor 9 is connected to the gate of an external switch. The common junction of the second series diode 10 is connected to the drive resistor 11, and the other terminal of the secondary winding of the isolation transformer 4 is connected between the common junction of the second series diode 10 and the drive resistor 11. The other terminal of the drive resistor 11 is connected to the gate of the MOSFET 8. The input terminal of the second series diode 10 is connected to the source of the MOSFET 8, and the output terminal is connected to the source of the external switch. A third resistor 12 is connected in series with both the input and output terminals of the second series diode 10. The second series diode 10 can cooperate with the MOSFET 8 to form a discharge circuit, which can quickly discharge the circuit when the drive stops, thereby quickly shutting down the circuit.

[0028] The first series diode 6 and the second series diode 10 have the same structure, both consisting of two diodes connected in series, and the connection point between the two diodes is a common connection point.

[0029] This invention creates a primary drive module and a secondary drive module, together with an isolation transformer 4, to transmit the chip's drive signal to an external switching transistor. The separate drive of the primary drive module and the secondary drive module ensures the circuit's driving capability while avoiding signal interference.

[0030] Example 2: Based on the previous example, this example adds a compensation capacitor connected in series between the output terminal of the second series diode 10 and the source of the external switching transistor. This capacitor can compensate for the small source-source junction capacitance of the MOS transistor 8, thereby achieving a turn-off time delay.

[0031] Example 3, please refer to Figure 2 Based on the previous embodiment, this embodiment designs two parallel drive circuits based on the same dual-channel drive chip, which can be connected and used with two external switching transistors. By analogy, the present invention can be extended to more drive circuits to adapt to the connection and use of multiple external switching transistors.

[0032] In summary, this invention employs a dual-channel driver chip, with both the primary and secondary driver modules having two sets of components to achieve dual-channel driving. This makes it applicable to half-bridge and full-bridge topologies, offering good applicability and high practicality. The overall circuit structure is simple, and from an economic perspective, the isolation transformer 4 is easy to wind. The turns ratio of the primary and secondary windings can be adjusted according to the actual driving voltage, resulting in flexibility and low cost, thus possessing significant market application value. Therefore, this invention effectively overcomes the various shortcomings of existing technologies and has high industrial utilization value.

[0033] The above embodiments are merely illustrative of the principles and effects of this utility model and are not intended to limit the scope of this utility model. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of this utility model. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in this utility model should still be covered by the claims of this utility model.

Claims

1. A transformer isolation drive circuit for an on-board power supply, comprising an isolation transformer having one primary winding and two secondary windings; characterized in that, The circuit includes: The chip driver module uses a dual-channel driver chip U1, and the input terminal of the dual-channel driver chip U1 is used to receive external PWM signals. Two sets of primary drive modules, each set of primary drive modules includes a first resistor and a first series diode. The first resistor is connected in series between the connection terminal of the primary winding of the isolation transformer and the output terminal of the dual-channel drive chip U1. The common connection point of the first series diode is connected in parallel between the connection terminal of the primary winding of the isolation transformer and the first resistor. Two sets of secondary drive modules are provided. Each set of secondary drive modules includes a MOSFET, a second resistor, a second series diode, and a drive resistor. One connection terminal of the secondary winding of the isolation transformer is connected to both the second resistor and the drain of the MOSFET. The other end of the second resistor is connected to the gate of an external switch. The common junction of the second series diode is connected to the drive resistor. The other connection terminal of the secondary winding of the isolation transformer is connected between the common junction of the second series diode and the drive resistor. The other end of the drive resistor is connected to the gate of the MOSFET. The input terminal of the second series diode is connected to the source of the MOSFET, and the output terminal is connected to the source of the external switch.

2. The transformer isolation drive circuit for vehicle power supply according to claim 1, characterized in that: One of the primary drive modules also includes an electrolytic capacitor connected between the primary winding of the isolation transformer and the first resistor.

3. The transformer isolation drive circuit for vehicle power supply according to claim 1, characterized in that: The dual-channel driver chip U1 includes channel A and channel B, each channel having an independent enable control terminal, input terminal, and output terminal.

4. The transformer isolation drive circuit for the vehicle power supply according to claim 3, characterized in that: The enable control terminals of both channel A and channel B are connected to the power supply pins of the dual-channel driver chip U1 to ensure that channels A and B are always allowed to be used.

5. The transformer isolation drive circuit for vehicle power supply according to claim 1, characterized in that: A third resistor is connected in series at both the input and output terminals of the second series diode.

6. The transformer isolation drive circuit for vehicle power supply according to claim 1, characterized in that: The output terminal of the second series diode is connected in series with the source of the external switching transistor, and there is compensation between them.

7. The transformer isolation drive circuit for vehicle power supply according to claim 1, characterized in that: The MOS transistor is an N-channel transistor.

8. The transformer isolation drive circuit for vehicle power supply according to claim 1, characterized in that: The first series diode and the second series diode have the same structure, both consisting of two diodes connected in series, and the connection point between the two diodes is a common connection point.

Images