An output polarity reversing circuit and switching power supply

Abstract

The application discloses an output polarity reversing circuit, which comprises a first reverse control unit, a second reverse control unit and a reverse action unit; when the input voltage signal is a high level, the first reverse control unit and the second reverse control unit make the first output end of the reverse control unit output a reverse output voltage and the second output end output a forward output voltage; when the input voltage signal is a low level, the first reverse control unit and the second reverse control unit make the first output end of the reverse control unit output a forward output voltage and the second output end output a reverse output voltage. The application controls the positive and negative polarities of the output voltage according to the high and low levels of the input voltage signal through the first reverse control unit, the second reverse control unit and the reverse action unit, so that the effect of reversing the polarity of the output voltage of the power terminal is realized.

Description

Technical Field

[0001] This invention relates to the field of switching power supply electronics, and in particular to an output polarity reversal circuit and a switching power supply. Background Technology

[0002] With the development of electronic technology, switching power supplies have become increasingly widely used in daily life. Currently, very few switching power supplies on the market have an output voltage polarity reversal function; they are generally labeled with output voltages such as "12V" or "24V," indicating a single or multiple outputs. Such voltage outputs cannot meet the diverse application needs of customers. When switching power supplies are used in situations where manual operation is inconvenient, customers require that the terminal output voltage of the power supply reverse its polarity after operating for a period of time, without damaging the switching power supply and allowing it to continue operating normally. This requires adding a polarity reversal circuit at the output. However, current technology has not yet provided a circuit that effectively addresses output voltage polarity reversal. Summary of the Invention:

[0003] To address the aforementioned problems, this invention provides an output polarity reversal circuit and a switching power supply, thereby solving the technical problem that a single switching power supply cannot achieve output voltage polarity reversal.

[0004] To achieve the above objectives, the present invention adopts the following basic technical solution:

[0005] In a first aspect, embodiments of this application provide an output polarity reversal circuit, which includes a first reversal control unit, a second reversal control unit, and a reversal action unit;

[0006] The input terminal of the first reverse control unit is connected to an input voltage signal, the input terminal of the second reverse control unit is connected to an input voltage signal, the first output terminal of the first reverse control unit is connected to the first input terminal of the reverse action unit, the second output terminal of the first reverse control unit is connected to the third input terminal of the reverse action unit, the first output terminal of the second reverse control unit is connected to the fourth input terminal of the reverse action unit, and the second output terminal of the second reverse control unit is connected to the second input terminal of the reverse action unit.

[0007] When the input voltage signal is high, the first reverse control unit and the second reverse control unit cause the first output terminal of the reverse control unit to output a reverse output voltage and the second output terminal to output a positive output voltage.

[0008] When the input voltage signal is low, the first reverse control unit and the second reverse control unit cause the first output terminal of the reverse control unit to output a positive output voltage and the second output terminal to output a reverse output voltage.

[0009] In an exemplary embodiment of this application, the reverse action unit includes a first resistor, a second resistor, a third resistor, a fourth resistor, a first switch, a second switch, a third switch, and a fourth switch.

[0010] The gate of the first switching transistor is connected to the first output terminal of the first inverting control unit through the first resistor. The gate of the second switching transistor is connected to the second output terminal of the second inverting control unit through the second resistor. The gate of the third switching transistor is connected to the second output terminal of the first inverting control unit through the third resistor. The gate of the fourth switching transistor is connected to the first output terminal of the second inverting control unit through the fourth resistor. The drains of the first and fourth switching transistors are both connected to the power supply terminal. The source of the first switching transistor is connected to the drain of the second switching transistor. The source of the fourth switching transistor is connected to the drain of the third switching transistor. The sources of the second and third switching transistors are both connected to the ground terminal. The source of the fourth switching transistor serves as the first terminal output terminal of the first inverting control unit, and the source of the first switching transistor serves as the second terminal output terminal of the first inverting control unit.

[0011] In an exemplary embodiment of this application, the first reverse control unit includes a sixth resistor, a seventh resistor, an eighth resistor, a ninth resistor, a fifth switch, a sixth switch, and a first Zener diode. The first terminal of the eighth resistor is connected to the input voltage signal. The gate of the fifth switch is connected to the second terminal of the eighth resistor. The drain of the fifth switch is connected to the power supply terminal through the seventh resistor. The drain of the fifth switch is connected to the gate of the sixth switch. The drain of the fifth switch is connected to ground through the ninth resistor. The drain of the sixth switch is connected to the cathode of the first Zener diode. The cathode of the first Zener diode is connected to the power supply terminal through the sixth resistor. The sources of the fifth and sixth switches are both connected to ground. The cathode of the first Zener diode is connected to the first input terminal of the reverse operation unit, and the anode of the first Zener diode is connected to the third input terminal of the reverse operation unit.

[0012] In an exemplary embodiment of this application, the second reverse control unit includes a fifth resistor, a tenth resistor, a seventh switch, and a second Zener diode. The first terminal of the tenth resistor is connected to the input voltage signal, the second terminal of the tenth resistor is connected to the gate of the seventh switch, the drain of the seventh switch is connected to the power supply terminal through the fifth resistor, the source of the seventh switch is connected to the ground terminal, the drain of the seventh switch is connected to the cathode of the second Zener diode, the cathode of the second Zener diode is connected to the fourth input terminal of the reverse operation unit, and the anode of the second Zener diode is connected to the second input terminal of the reverse operation unit.

[0013] In an exemplary embodiment of this application, the first switch, the second switch, the third switch, and the fourth switch are all NMOS transistors.

[0014] In an exemplary embodiment of this application, both the fifth switch and the sixth switch are NMOS transistors.

[0015] In an exemplary embodiment of this application, the seventh switch is an NMOS transistor.

[0016] Secondly, embodiments of this application provide a switching power supply, including the output polarity reversal circuit as described in the first aspect.

[0017] Compared with the prior art, the present invention has the following advantages:

[0018] This invention uses a first reverse control unit, a second reverse control unit, and a reverse action unit to control the polarity of the output voltage according to the high and low levels of the input voltage signal, thereby achieving the effect of reversing the polarity of the power supply terminal output voltage. Moreover, the circuit of this invention is simple, the cost is low, and it greatly improves the practicality of the power supply. Attached Figure Description

[0019] Figure 1 This is a block diagram illustrating the principle of an output polarity reversal circuit according to the present invention.

[0020] Figure 2 This is a circuit diagram of the first reverse control unit in an output polarity reverse circuit of the present invention;

[0021] Figure 3 This is a circuit diagram of the second reverse control unit in an output polarity reverse circuit of the present invention;

[0022] Figure 4 This is a circuit diagram of the reverse action unit in an output polarity reverse circuit according to the present invention. Detailed implementation method:

[0023] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings and specific embodiments:

[0024] refer to Figure 1 This application provides an output polarity reversal circuit, which includes a first reversal control unit 100, a second reversal control unit 200, and a reversal action unit 300.

[0025] The input terminal of the first reverse control unit 100 is connected to the input voltage signal Vctr, the input terminal of the second reverse control unit 200 is connected to the input voltage signal Vctr, the first output terminal of the first reverse control unit 100 is connected to the first input terminal of the reverse action unit 300, the second output terminal of the first reverse control unit 100 is connected to the third input terminal of the reverse action unit 300, the first output terminal of the second reverse control unit 200 is connected to the fourth input terminal of the reverse action unit 300, and the second output terminal of the second reverse control unit 200 is connected to the second input terminal of the reverse action unit 300.

[0026] When the input voltage signal Vctr is high, the first reverse control unit 100 and the second reverse control unit 200 cause the first output terminal of the reverse control unit to output a reverse output voltage and the second output terminal to output a positive output voltage.

[0027] When the input voltage signal Vctr is low, the first reverse control unit 100 and the second reverse control unit 200 cause the first output terminal of the reverse control unit to output a positive output voltage and the second output terminal to output a reverse output voltage.

[0028] This invention is used to realize the positive and negative switching of the output voltage of a switching power supply terminal. In this embodiment, the specific operating states are as follows:

[0029] The input voltage signal Vctr is high; the second terminal output OUT2 is positive, and the first terminal output OUT1 is negative;

[0030] The input voltage signal Vctr is low; the first terminal output OUT1 is positive, and the second terminal output OUT2 is negative.

[0031] refer to Figure 2 In one embodiment, the reverse action unit 300 includes a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, a first switch Q1, a second switch Q2, a third switch Q3, and a fourth switch Q4.

[0032] The gate of the first switch Q1 is connected to the first output terminal of the first inverting control unit 100 through the first resistor R1. The gate of the second switch Q2 is connected to the second output terminal of the second inverting control unit 200 through the second resistor R2. The gate of the third switch Q3 is connected to the second output terminal of the first inverting control unit 100 through the third resistor R3. The gate of the fourth switch Q4 is connected to the first output terminal of the second inverting control unit 200 through the fourth resistor R4. The drains of the first switch Q1 and the fourth switch Q4 are both connected to the power supply terminal. The source of the first switch Q1 is connected to the drain of the second switch Q2. The source of the fourth switch Q4 is connected to the drain of the third switch Q3. The sources of the second switch Q2 and the third switch Q3 are both connected to the ground terminal. The source of the fourth switch Q4 serves as the first terminal output terminal of the first inverting control unit 100, and the source of the first switch Q1 serves as the second terminal output terminal of the first inverting control unit 100. The first switch Q1, the second switch Q2, the third switch Q3, and the fourth switch Q4 can be implemented using MOS transistors. In this embodiment, the first switch Q1, the second switch Q2, the third switch Q3, and the fourth switch Q4 are all NMOS transistors.

[0033] The working circuit of the reverse action unit 300 includes: ①VO1+→first switch Q1→OUT2→user load→OUT1→third switch Q3→AGND. ②VO1+→fourth switch Q4→OUT1→user load→OUT2→second switch Q2→AGND.

[0034] refer to Figure 3 In one embodiment, the first inverting control unit 100 includes a sixth resistor R6, a seventh resistor R7, an eighth resistor R8, a ninth resistor R9, a fifth switch Q5, a sixth switch Q6, and a first Zener diode ZD1. The first terminal of the eighth resistor R8 is connected to the input voltage signal Vctr. The gate of the fifth switch Q5 is connected to the second terminal of the eighth resistor R8. The drain of the fifth switch Q5 is connected to the power supply terminal through the seventh resistor R7. The drain of the fifth switch Q5 is connected to the gate of the sixth switch Q6. The drain of the fifth switch Q5 is connected to the ground terminal through the ninth resistor R9. The drain of the sixth switch Q6 is connected to the cathode of the first Zener diode ZD1. The cathode of the first Zener diode ZD1 is connected to the power supply terminal through the sixth resistor R6. The sources of the fifth switch Q5 and the sixth switch Q6 are both connected to the ground terminal. The cathode of the first Zener diode ZD1 is connected to the first input terminal of the inverting unit 300, and the anode of the first Zener diode ZD1 is connected to the third input terminal of the inverting unit 300. The fifth switch Q5 and the sixth switch Q6 can be implemented using switching devices such as MOSFETs, transistors, and field-effect transistors. In this embodiment, both the fifth switch Q5 and the sixth switch Q6 are NMOS transistors.

[0035] refer to Figure 4 In one embodiment, the second inverting control unit 200 includes a fifth resistor R5, a tenth resistor R10, a seventh switch Q7, and a second Zener diode ZD2. The first terminal of the tenth resistor R10 is connected to the input voltage signal Vctr, and the second terminal of the tenth resistor R10 is connected to the gate of the seventh switch Q7. The drain of the seventh switch Q7 is connected to the power supply terminal through the fifth resistor R5, the source of the seventh switch Q7 is connected to ground, and the drain of the seventh switch Q7 is connected to the cathode of the second Zener diode ZD2. The cathode of the second Zener diode ZD2 is connected to the fourth input terminal of the inverting unit 300, and the anode of the second Zener diode ZD2 is connected to the second input terminal of the inverting unit 300. The seventh switch Q7 can be implemented using a MOSFET, transistor, field-effect transistor, or other switching device; in this embodiment, the seventh switch Q7 is an NMOS transistor.

[0036] After the system input is established, when the input voltage signal Vctr outputs a low level: ① The fifth switch Q5 is in the off state. The power supply signal Vcc at the power supply terminal provides a high level to the sixth switch Q6 after being divided by the seventh resistor R7 and the ninth resistor R9, so that it conducts and the connection potential point of the sixth resistor R6 / G1 signal terminal / first Zener diode ZD1 is grounded, and the first switch Q1 / third switch Q3 of the H-bridge is turned off; ② The seventh switch Q7 is in the off state. Vcc provides a high level to the gate of the fourth switch Q4 through the fifth resistor R5 → signal port G4 → fourth resistor R4. After the second Zener diode ZD2 regulates the voltage, it provides a high level to the gate of the second switch Q2 through the signal port G2 to the second resistor R2, and the second switch Q2 / fourth switch Q4 of the H-bridge are turned on; ③ The terminal output is as follows: the first terminal output terminal OUT1 = VO1+, and the second terminal output terminal OUT2 = GND.

[0037] After the system input is established, when the input voltage signal Vctr outputs a high level: ① The seventh switch Q7 is in the on state, the fifth resistor R5 / G4 signal terminal / second Zener diode ZD2 is grounded, and the second switch Q2 / fourth switch Q4 of the H-bridge is turned off; ② The fifth switch Q5 is in the on state, the seventh resistor R7 is short-circuited to GND, causing the sixth switch Q6 to lose its driving voltage and turn off, the G1 / G3 signal terminal returns to a high level, and the first switch Q1 / third switch Q3 of the H-bridge is turned on; ③ The terminal output is as follows: the first terminal output terminal OUT1 = GND, and the second terminal output terminal OUT2 = VO1+.

[0038] Under normal system input conditions, when the input voltage signal Vctr outputs a high level, the corresponding port OUT2 is + and OUT1 is -; when the input voltage signal Vctr outputs a low level, the corresponding port OUT1 is + and OUT2 is -.

[0039] In addition, this application also provides a switching power supply, including the output polarity reversing circuit as described in the above embodiments. The specific principle of the output polarity reversing circuit will not be elaborated further.

[0040] The above are merely preferred embodiments of the present invention. It should be noted that the above preferred embodiments should not be considered as limitations of the present invention. Figures 1 to 3 Based on the principle block diagram, those skilled in the art can make other improvements and modifications without departing from the spirit and scope of the present invention. These improvements and modifications are also within the protection scope of the present invention. They will not be elaborated here with examples. The protection scope of the present invention should be determined by the scope defined in the claims.

Claims

1. An output polarity reversal circuit, characterized in that: The output polarity reversing circuit includes a first reversing control unit, a second reversing control unit, and a reversing action unit; The input terminal of the first reverse control unit is connected to an input voltage signal, the input terminal of the second reverse control unit is connected to an input voltage signal, the first output terminal of the first reverse control unit is connected to the first input terminal of the reverse action unit, the second output terminal of the first reverse control unit is connected to the third input terminal of the reverse action unit, the first output terminal of the second reverse control unit is connected to the fourth input terminal of the reverse action unit, and the second output terminal of the second reverse control unit is connected to the second input terminal of the reverse action unit. When the input voltage signal is high, the first reverse control unit and the second reverse control unit cause the first output terminal of the reverse control unit to output a reverse output voltage and the second output terminal to output a positive output voltage. When the input voltage signal is low, the first reverse control unit and the second reverse control unit cause the first output terminal of the reverse control unit to output a positive output voltage and the second output terminal to output a reverse output voltage. The first reverse control unit includes a sixth resistor, a seventh resistor, an eighth resistor, a ninth resistor, a fifth switch, a sixth switch, and a first Zener diode. The first terminal of the eighth resistor is connected to the input voltage signal. The gate of the fifth switch is connected to the second terminal of the eighth resistor. The drain of the fifth switch is connected to the power supply terminal through the seventh resistor. The drain of the fifth switch is connected to the gate of the sixth switch. The drain of the fifth switch is connected to ground through the ninth resistor. The drain of the sixth switch is connected to the cathode of the first Zener diode. The cathode of the first Zener diode is connected to the power supply terminal through the sixth resistor. The sources of the fifth and sixth switches are both connected to ground. The cathode of the first Zener diode is connected to the first input terminal of the reverse operation unit, and the anode of the first Zener diode is connected to the third input terminal of the reverse operation unit.

2. The output polarity reversal circuit according to claim 1, characterized in that, The reverse action unit includes a first resistor, a second resistor, a third resistor, a fourth resistor, a first switch, a second switch, a third switch, and a fourth switch. The gate of the first switching transistor is connected to the first output terminal of the first inverting control unit through the first resistor. The gate of the second switching transistor is connected to the second output terminal of the second inverting control unit through the second resistor. The gate of the third switching transistor is connected to the second output terminal of the first inverting control unit through the third resistor. The gate of the fourth switching transistor is connected to the first output terminal of the second inverting control unit through the fourth resistor. The drains of the first and fourth switching transistors are both connected to the power supply terminal. The source of the first switching transistor is connected to the drain of the second switching transistor. The source of the fourth switching transistor is connected to the drain of the third switching transistor. The sources of the second and third switching transistors are both connected to the ground terminal. The source of the fourth switching transistor serves as the first terminal output terminal of the first inverting control unit, and the source of the first switching transistor serves as the second terminal output terminal of the first inverting control unit.

3. The output polarity reversal circuit according to claim 1, characterized in that: The second reverse control unit includes a fifth resistor, a tenth resistor, a seventh switch, and a second Zener diode. The first end of the tenth resistor is connected to the input voltage signal, the second end of the tenth resistor is connected to the gate of the seventh switch, the drain of the seventh switch is connected to the power supply terminal through the fifth resistor, the source of the seventh switch is connected to ground, the drain of the seventh switch is connected to the cathode of the second Zener diode, the cathode of the second Zener diode is connected to the fourth input terminal of the reverse operation unit, and the anode of the second Zener diode is connected to the second input terminal of the reverse operation unit.

4. The output polarity reversal circuit according to claim 2, characterized in that, The first switch, the second switch, the third switch, and the fourth switch are all NMOS transistors.

5. The output polarity reversal circuit according to claim 1, characterized in that, Both the fifth and sixth switching transistors are NMOS transistors.

6. The output polarity reversal circuit according to claim 3, characterized in that, The seventh switch is an NMOS transistor.

7. A switching power supply, characterized in that: Includes the output polarity reversing circuit as described in any one of claims 1-6.

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