Voltage conversion isolation circuit and electronic product

Abstract

The utility model discloses a voltage conversion isolation circuit and an electronic product, and relates to the technical field of circuit design. The circuit comprises a voltage conversion chip, a transformer T1 and an optocoupler. The voltage conversion chip is located on the primary side of the transformer T1 and used for receiving and converting input voltage, outputting the converted voltage to a load located on the secondary side of the transformer T1 and providing proper voltage and current for the load. In addition, electrical isolation is achieved through an optical coupler, the voltage of the output end is fed back to the voltage conversion chip, and real-time adjustment of the output voltage is achieved. According to the circuit and the electronic product comprising the same, the input voltage can be converted into the voltage adaptive to the load, and the input voltage side and the load side are isolated, so that the safety of the circuit is improved.

Description

Technical Field

[0001] This application relates to the technical field of circuit design, and in particular, to a voltage conversion isolation circuit and an electronic product. Background Art

[0002] In the industrial and communication fields, when powering a load, the input voltage provided by the power supply often cannot directly meet the requirements of the load; or, when the load power is large, if there is no certain isolation between the load and the input voltage of the power supply, when there are voltage surges and voltage spikes on one side of the circuit, it may also affect the other side of the circuit.

[0003] Therefore, there is an urgent need to design a circuit that can not only convert the input voltage into a voltage suitable for the load, but also isolate the input voltage side from the load side to improve the circuit safety. Utility Model Content

[0004] In order to convert the input voltage into a voltage suitable for the load and at the same time isolate the input voltage side from the load side, this application provides a voltage conversion isolation circuit.

[0005] In a first aspect, this application provides a voltage conversion isolation circuit, which includes a voltage conversion chip, resistor R4, resistor R5, resistor R6, resistor R7, resistor R8, resistor R9, resistor R10, resistor R11, resistor R12, resistor R13, capacitor C4, capacitor C5, capacitor C6, capacitor C7, capacitor C8, energy storage capacitors EC1, EC2, EC3, diode D3, transformer T1, optocoupler, inductor L1, and voltage reference chip U3; the voltage conversion chip includes an input undervoltage detection pin, an input overvoltage detection pin, a switching frequency setting pin, a power transistor drain pin, a chip power supply pin, an error amplifier output pin, and a feedback pin.

[0006] The input undervoltage detection pin is respectively connected to the first ends of resistor R5 and resistor R11; the input overvoltage detection pin is respectively connected to the second end of resistor R11, the first end of resistor R13, and the first end of capacitor C7; the switching frequency setting pin is connected to the first end of capacitor C8, and the error amplifier output pin is connected to the first end of capacitor C6 and the collector of the triode in the optocoupler; the second end of resistor R13 is respectively connected to the second end of capacitor C7, the second end of capacitor C8, the feedback pin, the second end of capacitor C6, the first end of capacitor C4, the first end of the auxiliary winding of transformer T1, the emitter of the triode in the optocoupler, and the negative end of the input voltage, and the feedback pin is also grounded.

[0007] The second terminal of the resistor R5 is respectively connected to the positive electrode of the energy storage capacitor EC3, the first terminal of the primary winding of the transformer T1, and the positive terminal of the input voltage; the negative electrode of the energy storage capacitor EC3 is grounded; the second terminal of the primary winding of the transformer T1 is connected to the drain pin of the power transistor; the second terminal of the auxiliary winding of the transformer T1 is connected to the first terminal of the resistor R4, the second terminal of the resistor R4 is connected to the anode of the diode D3, and the cathode of the diode D3 is respectively connected to the second terminal of the capacitor C4 and the power supply pin of the chip;

[0008] The first terminal of the secondary winding of the transformer T1 is respectively connected to the first terminal of the resistor R6, the positive electrode of the energy storage capacitor EC1, and the first terminal of the inductor L1; the second terminal of the inductor L1 is respectively connected to the positive electrode of the energy storage capacitor EC2, the first terminal of the resistor R7, and the load; the second terminal of the secondary winding of the transformer T1 is respectively connected to the negative electrode of the energy storage capacitor EC1, the negative electrode of the energy storage capacitor EC2, the first terminal of the resistor R12, and the anode of the voltage reference chip U3; the second terminal of the secondary winding of the transformer T1 is also grounded;

[0009] The second terminal of the resistor R7 is connected to the first terminal of the resistor R9; the second terminal of the resistor R9 is respectively connected to the second terminal of the resistor R12, the reference terminal of the voltage reference chip U3, and the first terminal of the resistor R10; the second terminal of the resistor R10 is connected to the first terminal of the capacitor C5; the second terminal of the capacitor C5 is respectively connected to the cathode of the voltage reference chip U3, the first terminal of the resistor R9, and the cathode of the diode in the optocoupler; the second terminal of the resistor R9 is respectively connected to the anode of the diode in the optocoupler and the second terminal of the resistor R6.

[0010] By adopting the above technical solution, using the voltage conversion chip as the main processing chip, combined with the construction of the transformer T1 and related circuits, the conversion isolation circuit can convert the input voltage into a voltage suitable for the load according to the actual situation of the load, ensuring the normal operation of the load; in addition, the optocoupler is used to achieve electrical isolation between the input voltage side and the load side, improving the circuit safety. The optocoupler can also timely feedback the voltage output to the load to the voltage conversion chip, realizing the feedback regulation of the output voltage and improving the conversion accuracy of the voltage.

[0011] In a specific feasible implementation, the circuit further includes a resistor R3, a resistor R3A, a diode D2, and a capacitor C3;

[0012] The first terminal of the resistor R3A is respectively connected to the second terminal of the resistor R5, the positive terminal of the input voltage, the positive electrode of the energy storage capacitor EC3, the first terminal of the resistor R3, the first terminal of the capacitor C3, and the first terminal of the primary winding of the transformer T1;

[0013] The second end of the resistor R3A is respectively connected to the second end of the resistor R3, the second end of the capacitor C3, and the cathode of the diode D2; the anode of the diode D2 is respectively connected to the second end of the primary winding of the transformer T1 and the drain pin of the power transistor.

[0014] By adopting the above technical solution, the resistor R3, the resistor R3A, the diode D2, and the capacitor C3 form an RCD absorption circuit, which is used to absorb the spike voltage in the circuit and play a good protection role.

[0015] In a specific feasible implementation, the circuit further includes a capacitor C2 and a resistor R2; the first end of the capacitor C2 is respectively connected to the second end of the inductor L1, the positive electrode of the energy storage capacitor EC2, the first end of the resistor R7, the first end of the resistor R2, and the load;

[0016] The second end of the capacitor C2 is respectively connected to the second end of the secondary winding of the transformer T1, the negative electrode of the energy storage capacitor EC1, the negative electrode of the energy storage capacitor EC2, the second end of the resistor R2, the first end of the resistor R12, and the anode of the voltage reference chip U3.

[0017] By adopting the above technical solution, an RC filter circuit is formed by the capacitor C2 and the resistor R2, which is used to filter the voltage output from the secondary winding side of the transformer T1 and improve the stability of the circuit.

[0018] In a specific feasible implementation, the circuit further includes a diode D1; the diode D1 is connected between the first end of the secondary winding of the transformer T1 and the inductor L1;

[0019] The anode of the diode D1 is connected to the first end of the secondary winding of the transformer T1; the cathode of the diode D1 is connected to the first end of the inductor L1.

[0020] By adopting the above technical solution, by using the unidirectional conduction function of the diode D1, the reverse current is avoided, and the safety during the use of the circuit and the load is improved.

[0021] In a specific feasible implementation, the circuit further includes a resistor R1 and a capacitor C1; after the resistor R1 and the capacitor C1 are connected in series, they are connected in parallel across the two ends of the diode D1.

[0022] In a specific feasible implementation, the input voltage is a DC voltage of 30V - 100V, and the output voltage and current of the voltage conversion isolation circuit are +12V, 0.83A or +5V, 2A.

[0023] In a specific feasible implementation, the output voltage and current of the voltage conversion isolation circuit are adjusted by adjusting the resistance values of the resistor R7, the resistor R9, the resistor R12, and the turn ratio of the transformer T1.

[0024] By adopting the above technical solution, those skilled in the art can flexibly replace the resistor R7, the resistor R9, the resistor R12, and the transformer T1 according to actual needs to achieve the adjustment of the output voltage and current.

[0025] In a second aspect, the present application provides an electronic product, and the electronic product includes the voltage conversion isolation circuit described in the first aspect or any feasible implementation of the first aspect.

[0026] To sum up, the technical solution of the present application at least includes the following beneficial technical effects:

[0027] 1. The present application uses a voltage conversion chip as the main processing chip, combined with the construction of the transformer T1 and related circuits, so that the conversion isolation circuit can convert the input voltage into a voltage adapted to the load according to the actual situation of the load to ensure the normal operation of the load; in addition, electrical isolation between the input voltage side and the load side is achieved by using an optocoupler, improving the circuit safety;

[0028] 2. The voltage output to the load can also be timely fed back to the voltage conversion chip through the optocoupler to achieve feedback regulation of the output voltage and improve the conversion accuracy of the voltage. Description of the Drawings

[0029] Figure 1 is the circuit diagram of the voltage conversion isolation circuit in the embodiment of the present application. Detailed Embodiments

[0030] To make the purpose, technical solution, and advantages of the present application clearer, the embodiments of the present application will be further described in detail below with reference to the drawings.

[0031] The present application discloses a voltage conversion isolation circuit, and the voltage conversion isolation circuit is used to convert the input voltage and then supply power to the load; as Figure 1 shown, the positive end of the input voltage is VIN+, and the negative end of the input voltage is VIN1; the input voltage is a DC voltage of 30V - 100V, and after the voltage conversion isolation circuit converts the input voltage, the output voltage and current of the voltage conversion isolation circuit are +12V, 0.83A or +5V, 2A.

[0032] Specifically, the circuit includes a voltage conversion chip, resistor R4, resistor R5, resistor R6, resistor R7, resistor R8, resistor R9, resistor R10, resistor R11, resistor R12, resistor R13, capacitor C4, capacitor C5, capacitor C6, capacitor C7, capacitor C8, energy storage capacitors EC1, EC2, EC3, diode D3, transformer T1, optocoupler, inductor L1, and voltage reference chip U3;

[0033] Among them, the voltage conversion chip includes an input undervoltage detection pin, an input overvoltage detection pin, a switching frequency setting pin, a power transistor drain pin, a chip power supply pin, an error amplifier output pin, and a feedback pin. As Figure 1 shown, the input undervoltage detection pin is the UV pin, the input overvoltage detection pin is the OV pin, the switching frequency setting pin is the CT pin, the power transistor drain pin is the VDRAIN pin, the chip power supply pin is the VCC pin, the error amplifier output pin is the COMP pin, and the feedback pin is the VFB pin.

[0034] The connection relationships of each component are as follows:

[0035] The input undervoltage detection pin is respectively connected to the first ends of resistor R5 and resistor R11; the input overvoltage detection pin is respectively connected to the second end of resistor R11, the first end of resistor R13, and the first end of capacitor C7; the switching frequency setting pin is connected to the first end of capacitor C8, and the error amplifier output pin is connected to the first end of capacitor C6 and the collector of the triode in the optocoupler;

[0036] The second end of resistor R13 is respectively connected to the second end of capacitor C7, the second end of capacitor C8, the feedback pin, the second end of capacitor C6, the first end of capacitor C4, the first end of the auxiliary winding of transformer T1, the emitter of the triode in the optocoupler, and the negative end of the input voltage, and the feedback pin is also grounded;

[0037] The second end of resistor R5 is respectively connected to the positive pole of energy storage capacitor EC3, the first end of the primary winding of transformer T1, and the positive end of the input voltage; the negative pole of energy storage capacitor EC3 is grounded; the second end of the primary winding of transformer T1 is connected to the power transistor drain pin;

[0038] The second end of the auxiliary winding of transformer T1 is connected to the first end of resistor R4, the second end of resistor R4 is connected to the anode of diode D3, and the cathode of diode D3 is respectively connected to the second end of capacitor C4 and the chip power supply pin;

[0039] The first end of the secondary winding of the transformer T1 is respectively connected to the first end of the resistor R6, the positive electrode of the energy storage capacitor EC1, and the first end of the inductor L1; the second end of the inductor L1 is respectively connected to the positive electrode of the energy storage capacitor EC2, the first end of the resistor R7, and the load;

[0040] The second end of the secondary winding of the transformer T1 is respectively connected to the negative electrode of the energy storage capacitor EC1, the negative electrode of the energy storage capacitor EC2, the first end of the resistor R12, and the anode of the voltage reference chip U3; the second end of the secondary winding of the transformer T1 is also grounded;

[0041] The second end of the resistor R7 is connected to the first end of the resistor R9, and the second end of the resistor R9 is respectively connected to the second end of the resistor R12, the reference terminal of the voltage reference chip U3, and the first end of the resistor R10; the second end of the resistor R10 is connected to the first end of the capacitor C5; the second end of the capacitor C5 is respectively connected to the cathode of the voltage reference chip U3, the first end of the resistor R9, and the cathode of the diode in the optocoupler; the second end of the resistor R9 is respectively connected to the anode of the diode in the optocoupler and the second end of the resistor R6.

[0042] Preferably, the model of the voltage conversion chip is PN8081, which is a DC-DC converter and has the advantage of high breakdown voltage. The model of the optocoupler is PC817A.

[0043] Furthermore, the voltage conversion chip realizes undervoltage sampling of the input voltage through the input undervoltage detection pin, and realizes overvoltage sampling of the input voltage through the input overvoltage detection pin. The voltage conversion chip adjusts the output voltage on the secondary side of the transformer T1 by changing the duty cycle of the PWM waveform output from the drain pin of the power transistor, that is, adjusts the voltage output to the load.

[0044] Therefore, in this application, the voltage conversion chip is used as the main processing chip, combined with the construction of the transformer T1 and related circuits, so that the conversion isolation circuit can convert the input voltage into a voltage suitable for the load according to the actual situation of the load, ensuring the normal operation of the load; in addition, the optocoupler is used to realize electrical isolation between the input voltage side and the load side, improving the circuit safety. The optocoupler can also timely feedback the voltage output to the load to the voltage conversion chip, and the voltage conversion chip adjusts the duty cycle of the PWM waveform output by the chip to realize feedback regulation of the output voltage and improve the conversion accuracy of the voltage.

[0045] In a possible implementation manner, as Figure 1 shown, the circuit further includes a resistor R3, a resistor R3A, a diode D2, and a capacitor C3;

[0046] The first terminal of the resistor R3A is connected to the second terminal of the resistor R5, the positive terminal of the input voltage, the positive electrode of the energy storage capacitor EC3, the first terminal of the resistor R3, the first terminal of the capacitor C3, and the first terminal of the primary winding of the transformer T1 respectively;

[0047] The second terminal of the resistor R3A is connected to the second terminal of the resistor R3, the second terminal of the capacitor C3, and the cathode of the diode D2 respectively; the anode of the diode D2 is connected to the second terminal of the primary winding of the transformer T1 and the drain pin of the power transistor respectively.

[0048] The resistors R3, R3A, diode D2 and capacitor C3 form an RCD absorption circuit for absorbing the spike voltage in the circuit and playing a good protection role.

[0049] In a possible implementation manner, as Figure 1 shown, the circuit further includes a capacitor C2 and a resistor R2;

[0050] The first terminal of the capacitor C2 is connected to the second terminal of the inductor L1, the positive electrode of the energy storage capacitor EC2, the first terminal of the resistor R7, the first terminal of the resistor R2, and the load respectively;

[0051] The second terminal of the capacitor C2 is connected to the second terminal of the secondary winding of the transformer T1, the negative electrode of the energy storage capacitor EC1, the negative electrode of the energy storage capacitor EC2, the second terminal of the resistor R2, the first terminal of the resistor R12, and the anode of the voltage reference chip U3 respectively.

[0052] The capacitor C2 and the resistor R2 form an RC filtering circuit for filtering the voltage output on the secondary winding side of the transformer T1 to improve the circuit stability.

[0053] In a possible implementation manner, as Figure 1 shown, the circuit further includes a diode D1; the diode D1 is connected between the first terminal of the secondary winding of the transformer T1 and the inductor L1;

[0054] The anode of the diode D1 is connected to the first terminal of the secondary winding of the transformer T1; the cathode of the diode D1 is connected to the first terminal of the inductor L1.

[0055] By utilizing the one-way conduction effect of the diode D1, the reverse current is avoided, and the safety during the use of the circuit and the load is improved.

[0056] In a possible implementation manner, as Figure 1 shown, the circuit further includes a resistor R1 and a capacitor C1; after the resistor R1 and the capacitor C1 are connected in series, they are connected in parallel across the two ends of the diode D1.

[0057] Specifically, the first end of the resistor R1 is connected to the anode of the diode D1, and the second end of the resistor R1 is connected to the first end of the capacitor C1; the second end of the capacitor C1 is connected to the cathode of the diode D1.

[0058] In a possible implementation manner, by adjusting the resistance value of the resistor R7, the resistance value of the resistor R9, the resistance value of the resistor R12, and the turn ratio of the transformer T1, the output voltage and current of the voltage conversion isolation circuit are adjusted.

[0059] Those skilled in the art can flexibly replace the resistor R7, the resistor R9, the resistor R12, and the transformer T1 according to actual needs to achieve the adjustment of the output voltage and current.

[0060] The embodiment of the present application provides an electronic product, and the electronic product includes the voltage conversion isolation circuit described in the above embodiment.

[0061] The above are all the preferred embodiments of the present application, and do not limit the protection scope of the present application accordingly. Therefore, all equivalent changes made according to the structure, shape, and principle of the present application shall be covered within the protection scope of the present application.

Claims

1. A voltage conversion isolation circuit, characterized in that: It includes a voltage conversion chip, a resistor R4, a resistor R5, a resistor R6, a resistor R7, a resistor R8, a resistor R9, a resistor R10, a resistor R11, a resistor R12, a resistor R13, a capacitor C4, a capacitor C5, a capacitor C6, a capacitor C7, a capacitor C8, an energy storage capacitor EC1, an energy storage capacitor EC2, an energy storage capacitor EC3, a diode D3, a transformer T1, an optocoupler, an inductor L1, and a voltage reference chip U3; the voltage conversion chip includes an input undervoltage detection pin, an input overvoltage detection pin, a switching frequency setting pin, a power tube drain pin, a chip power supply pin, an error amplifier output pin, and a feedback pin; The input undervoltage detection pin is respectively connected to the first end of the resistor R5 and the first end of the resistor R11; the input overvoltage detection pin is respectively connected to the second end of the resistor R11, the first end of the resistor R13, and the first end of the capacitor C7; the switching frequency setting pin is connected to the first end of the capacitor C8, and the error amplifier output pin is connected to the first end of the capacitor C6 and the collector of the transistor in the optocoupler; the second end of the resistor R13 is respectively connected to the second end of the capacitor C7, the second end of the capacitor C8, the feedback pin, the second end of the capacitor C6, the first end of the capacitor C4, the first end of the auxiliary winding of the transformer T1, the emitter of the transistor in the optocoupler and the negative end of the input voltage, and the feedback pin is also grounded; The second end of the resistor R5 is respectively connected to the positive electrode of the energy storage capacitor EC3, the first end of the primary winding of the transformer T1 and the positive end of the input voltage; the negative electrode of the energy storage capacitor EC3 is grounded; the second end of the primary winding of the transformer T1 is connected to the drain pin of the power tube; the second end of the auxiliary winding of the transformer T1 is connected to the first end of the resistor R4, the second end of the resistor R4 is connected to the anode of the diode D3, and the cathode of the diode D3 is respectively connected to the second end of the capacitor C4 and the chip power supply pin; The first end of the secondary winding of the transformer T1 is respectively connected to the first end of the resistor R6, the positive electrode of the energy storage capacitor EC1 and the first end of the inductor L1; the second end of the inductor L1 is respectively connected to the positive electrode of the energy storage capacitor EC2, the first end of the resistor R7 and the load; the second end of the secondary winding of the transformer T1 is respectively connected to the negative electrode of the energy storage capacitor EC1, the negative electrode of the energy storage capacitor EC2, the first end of the resistor R12 and the anode of the voltage reference chip U3; the second end of the secondary winding of the transformer T1 is also grounded; The second end of the resistor R7 is connected to the first end of the resistor R9; the second end of the resistor R9 is respectively connected to the second end of the resistor R12, the reference end of the voltage reference chip U3, and the first end of the resistor R10; the second end of the resistor R10 is connected to the first end of the capacitor C5; the second end of the capacitor C5 is respectively connected to the cathode of the voltage reference chip U3, the first end of the resistor R9, and the cathode of the diode in the optocoupler; the second end of the resistor R9 is respectively connected to the anode of the diode in the optocoupler and the second end of the resistor R6.

2. The voltage conversion isolation circuit according to claim 1, characterized in that: Also includes a resistor R3, a resistor R3A, a diode D2 and a capacitor C3; The first end of the resistor R3A is respectively connected to the second end of the resistor R5, the positive end of the input voltage, the positive electrode of the energy storage capacitor EC3, the first end of the resistor R3, the first end of the capacitor C3 and the first end of the primary winding of the transformer T1; The second end of the resistor R3A is respectively connected to the second end of the resistor R3, the second end of the capacitor C3 and the cathode of the diode D2; the anode of the diode D2 is respectively connected to the second end of the primary winding of the transformer T1 and the drain pin of the power tube.

3. The voltage conversion isolation circuit according to claim 1, characterized in that: It also includes capacitor C2 and resistor R2; The first end of the capacitor C2 is respectively connected to the second end of the inductor L1, the positive electrode of the energy storage capacitor EC2, the first end of the resistor R7, the first end of the resistor R2 and the load; The second end of the capacitor C2 is respectively connected to the second end of the secondary winding of the transformer T1, the negative electrode of the energy storage capacitor EC1, the negative electrode of the energy storage capacitor EC2, the second end of the resistor R2, the first end of the resistor R12 and the anode of the voltage reference chip U3.

4. The voltage conversion isolation circuit according to claim 1, characterized in that: It also includes a diode D1; the diode D1 is connected between the first end of the secondary winding of the transformer T1 and the inductor L1; The anode of the diode D1 is connected to the first end of the secondary winding of the transformer T1 ; the cathode of the diode D1 is connected to the first end of the inductor L1 .

5. The voltage conversion isolation circuit according to claim 4, characterized in that: It also includes a resistor R1 and a capacitor C1; the resistor R1 and the capacitor C1 are connected in series and then connected in parallel to both ends of the diode D1.

6. The voltage conversion isolation circuit according to claim 1, characterized in that: The input voltage is a direct current voltage of 30V-100V, and the output voltage and current of the voltage conversion isolation circuit are +12V, 0.83A or +5V, 2A.

7. The voltage conversion isolation circuit according to claim 1, characterized in that: The output voltage and current of the voltage conversion isolation circuit are adjusted by adjusting the resistance value of the resistor R7, the resistance value of the resistor R9, the resistance value of the resistor R12, and the turns ratio of the transformer T1.

8. An electronic product, characterized in that: The invention comprises the voltage conversion isolation circuit as described in any one of claims 1 to 7.

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