Direct current transmission circuit and isolation auxiliary power supply

Abstract

The utility model relates to the technical field of switching power supplies, in particular to a direct-current transmission circuit and an isolation auxiliary power supply. The direct current transmission circuit comprises a voltage stabilization module and an isolation output module composed of a transformer. The input end of the voltage stabilizing module is connected with an external input direct current source, and the output end of the voltage stabilizing module is connected with a first primary winding of the transformer; the voltage stabilization module is used for converting an input direct current voltage of an external input direct current source into a preset first direct current voltage and transmitting the first direct current voltage to the isolation output module; and the isolation output module is used for outputting second direct-current voltage physically isolated from the first direct-current voltage by the secondary winding when the first primary winding of the transformer receives the first direct-current voltage. By arranging the voltage stabilizing module, input in a wide voltage range can be achieved, the stable direct current output capacity can be achieved, meanwhile, physical isolation of output and input voltage is achieved through the transformer, and the anti-interference capacity of power supply operation is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of switching power supplies, in particular to a direct current transmission circuit and an isolated auxiliary power supply. Background Art

[0002] The switching power supply is the heart of all kinds of electronic devices. It converts and adjusts voltage and current by controlling the opening and closing of power tubes to meet power supply needs. It plays a very important role in the hardware industry. Among them, the isolated auxiliary power supply is a power supply that provides electrical isolation and supplies power to specific auxiliary systems. Although the isolated auxiliary power supply is an auxiliary system and generally has low power, it still needs to ensure high reliability and stability. At the same time, due to the inconsistent power supply requirements of different chips, it is necessary to output multiple DC power supplies with different voltages. Since these systems are not the core part of the application, as few resources as possible should be spent to complete the work.

[0003] At present, the most commonly used method for DC isolation is to use DC-DC modules. The disadvantages of this solution are: 1. The input power range is limited and cannot meet the requirements of wide power input; 2. The isolation distance is limited and the insulation degree is difficult to meet the requirements; 3. Multiple power supplies with different voltages require multiple DC-DCs, which will also increase costs.

[0004] The above contents are only used to assist in understanding the technical solution of the present utility model and do not constitute an admission that the above contents are prior art. Utility Model Content

[0005] The main purpose of the utility model is to provide a DC transmission circuit and an isolated auxiliary power supply, aiming to solve the technical problems in the prior art that the isolation distance of the DC power supply is limited and the cost required to improve the insulation degree is high.

[0006] To achieve the above object, the utility model provides a DC transmission circuit comprising: a voltage stabilizing module and an isolation output module composed of a transformer;

[0007] The input end of the voltage stabilizing module is connected to an external input DC source, and the output end of the voltage stabilizing module is connected to the first primary winding of the transformer;

[0008] The voltage stabilizing module is used to convert the input DC voltage of the external input DC source into a preset first DC voltage, and transmit the first DC voltage to the isolation output module;

[0009] The isolated output module is used for, when the first primary winding of the transformer receives the first DC voltage, the secondary winding outputs a second DC voltage that is physically isolated from the first DC voltage.

[0010] Optionally, the voltage stabilizing module comprises: a voltage stabilizing chip, a first resistor and a second resistor;

[0011] The input end of the voltage stabilizing chip is connected to an external input DC source, the output end of the voltage stabilizing chip is simultaneously connected to the first end of the first resistor and the first primary winding of the transformer, the second end of the first resistor is simultaneously connected to the first end of the second resistor and the feedback end of the voltage stabilizing chip, and the second end of the second resistor is grounded.

[0012] Optionally, the voltage stabilizing module further includes: a first inductor, a first diode and a first capacitor;

[0013] The output end of the voltage stabilizing chip is connected to the first end of the first inductor and the cathode of the first diode at the same time, the second end of the first inductor is connected to the first end of the first capacitor, the first end of the first resistor and the first primary winding of the transformer at the same time, and the anode of the first diode and the second end of the first capacitor are grounded.

[0014] Optionally, the isolated output module further includes: a switch control unit and a first rectifier unit;

[0015] The first end of the first primary winding of the transformer is connected to the output end of the voltage stabilizing module, the second end of the first primary winding of the transformer is connected to the input end of the switch control unit, the output end of the switch control unit is grounded, and the first rectifier unit is connected to the secondary winding of the transformer;

[0016] The switch control unit is used to conduct the loop of the first primary winding of the transformer to receive the first DC voltage at a preset frequency;

[0017] The first rectifying unit is used for rectifying the second DC voltage of the secondary winding and then outputting it.

[0018] Optionally, the switch control unit includes: a first switch tube and a waveform generating chip;

[0019] The input end of the first switch tube is connected to the second end of the first primary winding, the output end of the first switch tube is grounded, the control end of the first switch tube is connected to the output end of the waveform generating chip, and the input end of the waveform generating chip is connected to the output end of the voltage stabilizing module.

[0020] Optionally, the first rectifying unit includes: a second diode and a second capacitor;

[0021] The anode of the second diode is connected to the first end of the secondary winding of the transformer, the cathode of the second diode is connected to the first end of the second capacitor, and the second end of the second capacitor is connected to the second end of the secondary winding of the transformer and is grounded.

[0022] Optionally, the transformer further includes: a second primary winding; the isolated output module further includes: a third diode and a third capacitor;

[0023] The second primary winding and the first primary winding share a battery core, the anode of the third diode is connected to the first end of the second primary winding of the transformer, the cathode of the third diode is connected to the first end of the third capacitor, and the second end of the third capacitor is connected to the second end of the second primary winding of the transformer and is grounded;

[0024] The isolated output module is further configured to enable the second primary winding of the transformer to output a third DC voltage physically isolated from the first DC voltage when the first primary winding of the transformer receives the first DC voltage.

[0025] Optionally, the DC transmission circuit further includes: an optical coupler power supply module;

[0026] The input end of the optical coupler power supply module is connected to the output end of the isolated output module, and the output end of the optical coupler power supply module is connected to the optical coupler of the isolated auxiliary power supply;

[0027] The optocoupler power supply module is used to convert the second DC voltage of the isolation output module into a power supply signal for driving the optocoupler to work.

[0028] Optionally, the optical coupler power supply module includes: a DC transformer chip, a third resistor and a fourth capacitor;

[0029] The input end of the DC transformer chip is connected to the output end of the isolation output module, the output end of the DC transformer chip is simultaneously connected to the first end of the third resistor and the first end of the fourth capacitor, the second end of the third resistor is connected to the optocoupler, and the second end of the fourth capacitor is grounded.

[0030] In addition, to achieve the above-mentioned purpose, the utility model also provides an isolated auxiliary power supply, and the isolated auxiliary power supply includes the DC transmission circuit as described above.

[0031] The technical solution of the utility model proposes a DC transmission circuit and an isolated auxiliary power supply. The DC transmission circuit includes: a voltage stabilizing module and an isolated output module composed of a transformer; the input end of the voltage stabilizing module is connected to an external input DC source, and the output end of the voltage stabilizing module is connected to the first primary winding of the transformer; the voltage stabilizing module is used to convert the input DC voltage of the external input DC source into a preset first DC voltage, and transmit the first DC voltage to the isolated output module; the isolated output module is used to output a second DC voltage physically isolated from the first DC voltage by the secondary winding when the first primary winding of the transformer receives the first DC voltage. By setting a voltage stabilizing module, inputs with a wide voltage range can all have the ability to have stable DC outputs, and at the same time, a transformer is used to achieve physical isolation between the output and input voltages, thereby improving the anti-interference ability of the power supply operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0033] Figure 1 It is a functional module diagram of the first embodiment of the DC transmission circuit of the utility model;

[0034] Figure 2 This is a circuit structure diagram of the second embodiment of the DC transmission circuit of the utility model;

[0035] Figure 3 This is a circuit structure diagram of the third embodiment of the DC transmission circuit of the utility model;

[0036] Figure 4 This is a circuit structure diagram of an optocoupler power supply module in the third embodiment of the DC transmission circuit of the utility model;

[0037] Figure 5 This is a functional module diagram of the isolated auxiliary power supply of the utility model.

[0038] Description of Figure Numbers:

[0039] Label name Label name R1~R3 The first to third resistors Vo2 Second DC voltage Q1 The first switch Vo3 The third DC voltage D1~D3 The first to third diodes Vcc Power supply signal C1~C4 The first to fourth capacitors 10 Voltage regulator module T1 transformer 20 Isolated output module OC Optocoupler 30 Optocoupler power supply module VIN External input DC source 201 Switch control unit Vo1 First DC voltage 202 The first rectifier unit

[0040] The realization of the purpose, functional features and advantages of the utility model will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0041] It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0042] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0043] It should be noted that all directional indications in the embodiments of the present invention (such as up, down, left, right, front, back...) are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0044] In addition, the descriptions of "first", "second", etc. in the present utility model are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the ability of ordinary technicians in this field to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present utility model.

[0045] Reference Figure 1 , Figure 1 The first embodiment of the DC transmission circuit of the utility model is a functional module diagram. The utility model provides a first embodiment of the DC transmission circuit.

[0046] In this embodiment, the DC transmission circuit includes: a voltage stabilizing module 10 and an isolated output module 20 formed by a transformer T1. The input end of the voltage stabilizing module 10 is connected to an external input DC source VIN, and the output end of the voltage stabilizing module 10 is connected to the first primary winding of the transformer T1.

[0047] It should be noted that the voltage stabilizing module 10 can be used to convert the input DC voltage of the external input DC source VIN into a preset first DC voltage Vo1, and transmit the first DC voltage Vo1 to the isolated output module 20; the isolated output module 20 can be used to output a second DC voltage Vo2 that is physically isolated from the first DC voltage Vo1 at the secondary winding when the first primary winding of the transformer receives the first DC voltage Vo1.

[0048] It should be understood that the voltage stabilizing module 10 may be an electronic device capable of converting different voltage amplitudes (generally in the range of 9 to 36V) of the external input DC source VIN into the first DC voltage with a constant voltage amplitude. The first DC voltage may be adjusted according to the requirements of the auxiliary power supply, for example, it may be set to 8V, and the specific value may not be limited.

[0049] Furthermore, the transformer can be an electronic device that changes the voltage at both ends of the input and output by changing the number of turns of the winding based on the principle of electromagnetic induction. The primary winding and the secondary winding of the transformer are physically isolated, which can isolate different potentials and prevent current from flowing directly between the two windings, and has high insulation strength. Therefore, the second DC voltage can be a voltage signal that is physically isolated from the first DC voltage and has a different amplitude. For example, by setting the number of turns of the primary winding and the secondary winding of the transformer, when the first DC voltage input to the primary winding is 8V, the amplitude of the second DC voltage induced by the secondary winding is 15V.

[0050] It should be understood that, due to the law of electromagnetic induction, the first DC voltage passed into the transformer needs to be a variable voltage in order to achieve the voltage transformation effect. Therefore, a device with a switching function (not shown in the figure) should also be provided on the primary winding side of the transformer to achieve a voltage change according to a preset ratio and output a second DC voltage of a corresponding amplitude on the secondary winding, wherein the device with the switching function may be a power tube, etc. Furthermore, the second DC voltage output by the secondary winding of the transformer at this time is also a variable voltage, so it is necessary to provide an electronic device with a rectifying and voltage stabilizing function (not shown in the figure) on the secondary winding side of the transformer to achieve a stable second DC voltage output effect, wherein the electronic device with a rectifying and voltage stabilizing function may be a diode, a capacitor, and an inductor, etc.

[0051] This embodiment proposes a DC transmission circuit and an isolated auxiliary power supply. The DC transmission circuit includes: a voltage stabilizing module and an isolated output module composed of a transformer; the input end of the voltage stabilizing module is connected to an external input DC source, and the output end of the voltage stabilizing module is connected to the first primary winding of the transformer; the voltage stabilizing module is used to convert the input DC voltage of the external input DC source into a preset first DC voltage, and transmit the first DC voltage to the isolated output module; the isolated output module is used to output a second DC voltage physically isolated from the first DC voltage by the secondary winding when the first primary winding of the transformer receives the first DC voltage. By setting a voltage stabilizing module, inputs with a wide voltage range can all have the ability to have stable DC outputs, and at the same time, a transformer is used to achieve physical isolation between the output and input voltages, thereby improving the anti-interference ability of the power supply operation.

[0052] Reference Figure 2 , Figure 2The second embodiment of the DC transmission circuit of the utility model is a circuit structure diagram. Based on the first embodiment of the DC transmission circuit, the second embodiment of the DC transmission circuit of the utility model is proposed.

[0053] In this embodiment, the voltage stabilizing module 10 includes: a voltage stabilizing chip U1, a first resistor R1, and a second resistor R2. The input end of the voltage stabilizing chip U1 is connected to an external input DC source VIN, the output end of the voltage stabilizing chip U1 is simultaneously connected to the first end of the first resistor R1 and the first primary winding of the transformer T1, the second end of the first resistor R1 is simultaneously connected to the first end of the second resistor R2 and the feedback end of the voltage stabilizing chip U1, and the second end of the second resistor R2 is grounded.

[0054] It should be noted that the voltage stabilizing chip U1 can generate a reference voltage at the feedback end, and the output voltage is fixed by the voltage division control of the first resistor R1 and the second resistor R2. The reference voltage is a voltage value of a fixed magnitude preset by the voltage stabilizing chip, and the amplitude of the first DC voltage Vo1 is stabilized by adjusting the ratio of the first resistor R1 and the second resistor R2.

[0055] Furthermore, the voltage stabilizing module 20 also includes: a first inductor L1, a first diode D1 and a first capacitor C1; the output end of the voltage stabilizing chip U1 is simultaneously connected to the first end of the first inductor L1 and the cathode of the first diode D1, the second end of the first inductor L1 is simultaneously connected to the first end of the first capacitor C1, the first end of the first resistor R1 and the first primary winding of the transformer T1, and the anode of the first diode D1 and the second end of the first capacitor C1 are grounded.

[0056] It should be understood that the filter circuit formed by the first inductor L1, the first diode D1 and the first capacitor C1 can filter out the reference AC ripple component in the first DC voltage, further improving the stability of the voltage amplitude.

[0057] This embodiment provides a voltage stabilizing module composed of a voltage stabilizing chip, a first resistor, and a second resistor to ensure that the input of the DC transmission circuit can have a wider range and adapt to application requirements in more scenarios. And it has a relatively stable DC output. At the same time, a filter circuit composed of a first inductor, a first diode, and a first capacitor is also provided at the output end of the voltage stabilizing chip to filter out the ripple component of the output end of the voltage stabilizing chip, further improving the stability of the signal output of the DC transmission circuit.

[0058] Reference Figure 3 , Figure 3 The third embodiment of the DC transmission circuit of the present invention is a circuit structure diagram of the third embodiment of the DC transmission circuit of the present invention. Based on the above embodiments of the DC transmission circuit, the third embodiment of the DC transmission circuit of the present invention is proposed.

[0059] In this embodiment, the isolated output module 20 further includes: a switch control unit 201 and a first rectifier unit 202. The first end of the first primary winding of the transformer T1 is connected to the output end of the voltage stabilizing module 10, the second end of the first primary winding of the transformer T1 is connected to the input end of the switch control unit 202, the output end of the switch control unit 201 is grounded, and the first rectifier unit 202 is connected to the secondary winding of the transformer T1.

[0060] It should be noted that the switch control unit 201 can be used to turn on the loop of the first primary winding of the transformer to receive the first DC voltage at a preset frequency; the first rectifying unit 202 can be used to rectify the second DC voltage of the secondary winding and then output it.

[0061] It should be understood that the primary winding of the transformer T1 needs to receive a DC power with a varying amplitude, and by setting the switch control unit 201 to be turned on and off, the amplitude of the first DC voltage input to the transformer changes periodically according to a preset frequency. Then, by setting the first rectifier unit 202, the varying voltage on the secondary side of the transformer T1 is converted into a stable DC voltage.

[0062] Furthermore, the switch control unit 201 includes: a first switch tube Q1 and a waveform generating chip U2. The input end of the first switch tube Q1 is connected to the second end of the first primary winding, the output end of the first switch tube Q1 is grounded, the control end of the first switch tube Q1 is connected to the output end of the waveform generating chip U2, and the input end of the waveform generating chip U2 is connected to the output end of the voltage stabilizing module 10.

[0063] It should be noted that the waveform generating chip U2 can be a functional chip with DC voltage conversion capability (such as an MC34063 chip) that can generate a periodically changing waveform at the output end in response to the input and a preset peripheral circuit to control the on and off of the first switch tube Q1, thereby achieving control of the voltage on the primary winding of the transformer.

[0064] Furthermore, the first rectifying unit 202 includes: a second diode Q2 and a second capacitor C2. The anode of the second diode Q2 is connected to the first end of the secondary winding of the transformer T1, the cathode of the second diode Q2 is connected to the first end of the second capacitor C2, and the second end of the second capacitor C2 is connected to the second end of the secondary winding of the transformer T1 and is grounded.

[0065] It should be noted that the second DC voltage generated on the secondary winding filters out the AC ripple component on the second DC voltage through the unidirectional conduction effect of the diode and the energy storage effect of the capacitor, thereby maintaining the stability of the second DC voltage.

[0066] Furthermore, the transformer T1 also includes: a second primary winding; the isolated output module also includes: a third diode D3 and a third capacitor C3; the second primary winding and the first primary winding share a battery core, the anode of the third diode D3 is connected to the first end of the second primary winding of the transformer T1, the cathode of the third diode D3 is connected to the first end of the third capacitor C3, and the second end of the third capacitor C3 is connected to the second end of the second primary winding of the transformer T1 and is grounded.

[0067] It should be noted that the isolated output module is further configured to enable the second primary winding of the transformer to output a third DC voltage Vo3 physically isolated from the first DC voltage Vo1 when the first primary winding of the transformer receives the first DC voltage.

[0068] It should be understood that the amplitude of the third DC voltage Vo3 is different from that of the second DC voltage Vo2. For example, when the amplitude of the second DC voltage Vo2 is 15V, the amplitude of the third DC voltage Vo3 is 12V.

[0069] Reference Figure 4 , Figure 4 This is a circuit structure diagram of an optocoupler power supply module in the third embodiment of the DC transmission circuit of the utility model.

[0070] The DC transmission circuit further includes: an optocoupler power supply module 30; the input end of the optocoupler power supply module 30 is connected to the output end of the isolated output module 20, and the output end of the optocoupler power supply module 30 is connected to the optocoupler OC of the isolated auxiliary power supply.

[0071] It should be noted that the optical coupler power supply module 30 can be used to convert the second DC voltage of the isolated output module 20 into a power supply signal Vcc for driving the optical coupler OC to work. An optical coupler is an electrical-optical-electrical conversion device that transmits electrical signals using light as a medium. It consists of a light source and a light receiver. The input and output parts are also physically isolated to enhance the isolation capability of the power supply.

[0072] Furthermore, the optocoupler power supply module 30 includes: a DC transformer chip U3, a third resistor R3 and a fourth capacitor C4; the input end of the DC transformer chip U3 is connected to the output end of the isolated output module 20, and the output end of the DC transformer chip U3 is simultaneously connected to the first end of the third resistor R3 and the first end of the fourth capacitor C4, the second end of the third resistor R3 is connected to the optocoupler OC, and the second end of the fourth capacitor C4 is grounded.

[0073] It should be understood that the driving voltage of the optocoupler is 5V, and the second DC voltage is converted into a 5V supply voltage of the optocoupler OC by setting the DC transformer chip U3.

[0074] In this embodiment, a switch control unit and a first rectifier unit are provided. The first end of the first primary winding of the transformer is connected to the output end of the voltage stabilizing module, the second end of the first primary winding of the transformer is connected to the input end of the switch control unit, the output end of the switch control unit is grounded, and the first rectifier unit is connected to the secondary winding of the transformer. The switch control unit is used to conduct the loop of the first primary winding of the transformer to receive the first DC voltage at a preset frequency; the first rectifier unit is used to rectify the second DC voltage of the secondary winding and then output it. Among them, the switch control unit includes: a first switch tube and a waveform generating chip. The first rectifier unit includes: a second diode and a second capacitor. A simple and low-cost circuit design is used to realize the ability of input with a wide voltage range to have a stable DC output, and at the same time, a transformer is used to realize the physical isolation of the output and input voltages, thereby improving the anti-interference ability of the power supply operation. Multiple different DC power supply voltages can be output at the same time.

[0075] In addition, the present invention also provides an isolated auxiliary power supply. Figure 5 , Figure 5 This is a functional module diagram of the isolated auxiliary power supply of the utility model. The isolated auxiliary power supply includes the above-mentioned DC transmission circuit.

[0076] Since the isolated auxiliary power supply adopts all the technical solutions of all the above embodiments, it has at least all the beneficial effects brought by the technical solutions of the above embodiments, which will not be described one by one here.

[0077] The above description is only a preferred embodiment of the utility model, and does not limit the patent scope of the utility model. All equivalent structural changes made by using the contents of the utility model specification and drawings under the utility model concept, or directly / indirectly used in other related technical fields are included in the patent protection scope of the utility model.

Claims

1. A DC transmission circuit, characterized in that: The DC transmission circuit is applied to an isolated auxiliary power supply, and the DC transmission circuit comprises: a voltage stabilizing module and an isolated output module composed of a transformer; The input end of the voltage stabilizing module is connected to an external input DC source, and the output end of the voltage stabilizing module is connected to the first primary winding of the transformer; The voltage stabilizing module is used to convert the input DC voltage of the external input DC source into a preset first DC voltage, and transmit the first DC voltage to the isolation output module; The isolated output module is used for, when the first primary winding of the transformer receives the first DC voltage, the secondary winding outputs a second DC voltage that is physically isolated from the first DC voltage.

2. The DC transmission circuit according to claim 1, characterized in that: The voltage stabilizing module comprises: a voltage stabilizing chip, a first resistor and a second resistor; The input end of the voltage stabilizing chip is connected to an external input DC source, the output end of the voltage stabilizing chip is simultaneously connected to the first end of the first resistor and the first primary winding of the transformer, the second end of the first resistor is simultaneously connected to the first end of the second resistor and the feedback end of the voltage stabilizing chip, and the second end of the second resistor is grounded.

3. The DC transmission circuit according to claim 2, characterized in that: The voltage stabilizing module further includes: a first inductor, a first diode and a first capacitor; The output end of the voltage stabilizing chip is connected to the first end of the first inductor and the cathode of the first diode at the same time, the second end of the first inductor is connected to the first end of the first capacitor, the first end of the first resistor and the first primary winding of the transformer at the same time, and the anode of the first diode and the second end of the first capacitor are grounded.

4. The DC transmission circuit according to claim 1, characterized in that: The isolated output module further includes: a switch control unit and a first rectifier unit; The first end of the first primary winding of the transformer is connected to the output end of the voltage stabilizing module, the second end of the first primary winding of the transformer is connected to the input end of the switch control unit, the output end of the switch control unit is grounded, and the first rectifier unit is connected to the secondary winding of the transformer; The switch control unit is used to conduct the loop of the first primary winding of the transformer to receive the first DC voltage at a preset frequency; The first rectifying unit is used for rectifying the second DC voltage of the secondary winding and then outputting it.

5. The DC transmission circuit according to claim 4, characterized in that: The switch control unit includes: a first switch tube and a waveform generating chip; The input end of the first switch tube is connected to the second end of the first primary winding, the output end of the first switch tube is grounded, the control end of the first switch tube is connected to the output end of the waveform generating chip, and the input end of the waveform generating chip is connected to the output end of the voltage stabilizing module.

6. The DC transmission circuit according to claim 4, characterized in that: The first rectifying unit comprises: a second diode and a second capacitor; The anode of the second diode is connected to the first end of the secondary winding of the transformer, the cathode of the second diode is connected to the first end of the second capacitor, and the second end of the second capacitor is connected to the second end of the secondary winding of the transformer and is grounded.

7. The DC transmission circuit according to claim 1, characterized in that: The transformer further includes: a second primary winding; the isolated output module further includes: a third diode and a third capacitor; The second primary winding and the first primary winding share a battery core, the anode of the third diode is connected to the first end of the second primary winding of the transformer, the cathode of the third diode is connected to the first end of the third capacitor, and the second end of the third capacitor is connected to the second end of the second primary winding of the transformer and is grounded; The isolated output module is further configured to enable the second primary winding of the transformer to output a third DC voltage physically isolated from the first DC voltage when the first primary winding of the transformer receives the first DC voltage.

8. The DC transmission circuit according to claim 1, characterized in that: The DC transmission circuit also includes: an optical coupler power supply module; The input end of the optical coupler power supply module is connected to the output end of the isolated output module, and the output end of the optical coupler power supply module is connected to the optical coupler of the isolated auxiliary power supply; The optocoupler power supply module is used to convert the second DC voltage of the isolation output module into a power supply signal for driving the optocoupler to work.

9. The DC transmission circuit according to claim 8, characterized in that: The optical coupler power supply module includes: a DC transformer chip, a third resistor and a fourth capacitor; The input end of the DC transformer chip is connected to the output end of the isolation output module, the output end of the DC transformer chip is simultaneously connected to the first end of the third resistor and the first end of the fourth capacitor, the second end of the third resistor is connected to the optocoupler, and the second end of the fourth capacitor is grounded.

10. An isolated auxiliary power supply, characterized in that: The isolated auxiliary power supply comprises: a DC transmission circuit as described in any one of claims 1-9.

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