Hysteresis constant voltage power supply circuit

Abstract

The present invention relates to a hysteresis constant-voltage power supply circuit. By providing a start switch unit, a first current-limiting resistor, a hysteresis voltage control unit, a second current-limiting resistor, and an output switch unit, the first end of the start switch unit is used to externally connect an input power supply voltage and is connected to the first end of the output switch unit. The second end of the start switch unit is connected to the first end of the hysteresis voltage control unit through the first current-limiting resistor. The third end of the start switch unit is connected to one end of the second current-limiting resistor. The other end of the second current-limiting resistor is respectively connected to the second end of the hysteresis voltage control unit and the second end of the output switch unit. The third end of the hysteresis voltage control unit is grounded. The third end of the output switch unit is used to output a constant target voltage. The above-mentioned hysteresis constant-voltage power supply circuit simplifies the structure of the hysteresis constant-voltage power supply circuit and improves the power quality of the power-consuming circuit.

Description

Technical Field

[0001] The present invention relates to the field of power supply circuits, and particularly to a hysteresis constant voltage power supply circuit. Background Art

[0002] Currently, traditional hysteresis control usually sets a comparison circuit, a logic circuit and a control circuit, and the control circuit and the logic circuit often need to be powered, and the overall circuit structure is often complex and cumbersome. Summary of the Invention

[0003] In view of this, the present invention provides a hysteresis constant voltage power supply circuit. Through the mutual cooperation of a start switch unit, a first current limiting resistor, a hysteresis voltage control unit, a second current limiting resistor and an output switch unit, when the power input voltage climbs to a first preset voltage threshold, the constant voltage power supply circuit immediately starts to output a constant target voltage; when the power input voltage drops below a second preset voltage threshold during the decline process, the constant voltage power supply circuit immediately cuts off the output. It does not require the use of a comparison circuit and a logic circuit, and does not require separate power supply for the control circuit, simplifies the structure of the hysteresis constant voltage power supply circuit, and outputs a constant target voltage to improve the power quality of the power consumption circuit.

[0004] A hysteresis constant voltage power supply circuit, the hysteresis constant voltage power supply circuit includes: a start switch unit, a first current limiting resistor, a hysteresis voltage control unit, a second current limiting resistor and an output switch unit;

[0005] The first end of the start switch unit is used for externally connecting an input power supply voltage and is connected to the first end of the output switch unit. The second end of the start switch unit is connected to the first end of the hysteresis voltage control unit through the first current limiting resistor. The third end of the start switch unit is connected to one end of the second current limiting resistor;

[0006] The other end of the second current limiting resistor is respectively connected to the second end of the hysteresis voltage control unit and the second end of the output switch unit. The third end of the hysteresis voltage control unit is grounded. The third end of the output switch unit is used for outputting a constant target voltage;

[0007] The hysteresis voltage control unit is used to control the start switch unit and the output switch unit to conduct when the input power supply voltage rises to the first preset voltage threshold, so that the output switch unit outputs a constant target voltage;

[0008] The hysteresis voltage control unit is further used to control the start switch unit and the output switch unit to turn off when the input power supply voltage drops to the second preset voltage threshold, and the second preset voltage threshold is less than the first preset voltage threshold.

[0009] In one embodiment, the hysteresis voltage control unit includes a first voltage stabilizing unit, a second voltage stabilizing unit and a hysteresis control switch;

[0010] One end of the first voltage stabilizing unit is respectively connected to one end of the first current limiting resistor and the first end of the hysteresis control switch, the other end of the first voltage stabilizing unit is grounded, the second end of the hysteresis control switch is respectively connected to one end of the second current limiting resistor and the second end of the output switch unit, one end of the second voltage stabilizing unit is connected to the third end of the hysteresis control switch, and the other end of the second voltage stabilizing unit is grounded;

[0011] Wherein, the first voltage stabilizing value corresponding to the first voltage stabilizing unit is greater than the second voltage stabilizing value corresponding to the second voltage stabilizing unit, the first voltage stabilizing value is less than the first preset voltage threshold, and the second voltage stabilizing value is less than the second preset voltage threshold.

[0012] In one embodiment, the first voltage stabilizing unit uses a first voltage stabilizing diode. The cathode of the first voltage stabilizing diode is connected to one end of the first current limiting resistor and the first end of the hysteresis control switch, and the anode of the first voltage stabilizing diode is grounded.

[0013] In one embodiment, the second voltage stabilizing unit uses a second voltage stabilizing diode. The cathode of the second voltage stabilizing diode is connected to the third end of the hysteresis control switch, and the anode of the second voltage stabilizing diode is grounded.

[0014] In one embodiment, the hysteresis control switch uses a triode or a MOS transistor.

[0015] In one embodiment, the hysteresis control switch uses an NPN triode. The collector of the NPN triode is the first end of the hysteresis control switch, the base of the NPN triode is the second end of the hysteresis control switch, and the emitter of the NPN triode is the third end of the hysteresis control switch.

[0016] In one embodiment, the hysteresis constant voltage power supply circuit further includes an anti-reverse connection unit. One end of the anti-reverse connection unit is used to connect to the input power supply voltage, and the other end of the anti-reverse connection unit is respectively connected to the first end of the start switch unit and the first end of the output switch unit.

[0017] In one embodiment, the anti-reverse connection unit uses a diode.

[0018] In one embodiment, the start switch unit uses a triode or a MOS transistor, and the output switch unit uses a triode or a MOS transistor.

[0019] In one embodiment, the start switch unit uses a PNP triode. The emitter of the PNP triode is the first end of the start switch unit, the base of the PNP triode is the second end of the start switch unit, and the collector of the PNP triode is the third end of the start switch unit.

[0020] In one embodiment, a hysteresis constant voltage power supply is further provided. The hysteresis constant voltage power supply adopts the above-mentioned hysteresis constant voltage power supply circuit.

[0021] The above-mentioned hysteresis constant-voltage power supply circuit is provided with a start switch unit, a first current-limiting resistor, a hysteresis voltage control unit, a second current-limiting resistor, and an output switch unit. The first end of the start switch unit is used to externally connect the input power supply voltage and is connected to the first end of the output switch unit. The second end of the start switch unit is connected to the first end of the hysteresis voltage control unit through the first current-limiting resistor. The third end of the start switch unit is connected to one end of the second current-limiting resistor. The other end of the second current-limiting resistor is respectively connected to the second end of the hysteresis voltage control unit and the second end of the output switch unit. The third end of the hysteresis voltage control unit is grounded. The third end of the output switch unit is used to output a constant target voltage. The hysteresis voltage control unit is used to control the start switch unit and the output switch unit to conduct when the input power supply voltage rises to the first preset voltage threshold, so that the output switch unit outputs a constant target voltage. The hysteresis voltage control unit is also used to control the start switch unit and the output switch unit to turn off when the input power supply voltage drops to the second preset voltage threshold, and the second preset voltage threshold is less than the first preset voltage threshold. Further, through the mutual cooperation of the start switch unit, the first current-limiting resistor, the hysteresis voltage control unit, the second current-limiting resistor, and the output switch unit, when the power supply input voltage reaches the first preset voltage threshold during the voltage climbing process, the output of the constant target voltage is immediately started; when the power supply input voltage is less than the second preset voltage threshold during the voltage drop process, the output is immediately cut off. The above-mentioned hysteresis constant-voltage power supply circuit does not need to use a comparison circuit and a logic circuit, and does not need to supply power to the control circuit separately, which simplifies the structure of the hysteresis constant-voltage power supply circuit and improves the power quality of the power consumption circuit. Description of the Drawings

[0022] In order to more clearly illustrate the technical solutions of the present invention, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention, and therefore should not be regarded as limiting the protection scope of the present invention. In each drawing, similar components are numbered similarly.

[0023] Figure 1 It is a structural block diagram of a hysteresis constant-voltage power supply circuit in an embodiment;

[0024] Figure 2 It is a structural schematic diagram of a hysteresis constant-voltage power supply circuit in an embodiment. Detailed Embodiments

[0025] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are only some of the embodiments of the present invention, rather than all of the embodiments.

[0026] The components of the embodiments of the present invention that are generally described and illustrated in the accompanying drawings herein can be arranged and designed in a variety of different configurations. Accordingly, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but is merely representative of selected embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative efforts fall within the scope of the present invention.

[0027] Hereinafter, various embodiments of the present disclosure will be described more fully. The present disclosure can have various embodiments and adjustments and changes can be made therein. However, it should be understood that there is no intention to limit the various embodiments of the present disclosure to the specific embodiments disclosed herein, but the present disclosure should be understood to cover all adjustments, equivalents, and / or alternative options falling within the spirit and scope of the various embodiments of the present disclosure.

[0028] Hereinafter, the terms "comprising", "having" and their cognates that can be used in various embodiments of the present invention are only intended to denote specific features, numbers, steps, operations, elements, components, or combinations of the foregoing items, and should not be construed as precluding the existence or adding the possibility of one or more other features, numbers, steps, operations, elements, components, or combinations of the foregoing items first.

[0029] In addition, the terms "first", "second", "third", etc. are only used for distinguishing descriptions and cannot be construed as indicating or implying relative importance.

[0030] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by those of ordinary skill in the art to which the various embodiments of the present invention belong. The terms (such as those defined in a commonly used dictionary) will be construed to have the same meaning as the contextual meaning in the relevant technical field and will not be construed to have an idealized meaning or an overly formal meaning unless clearly defined in the various embodiments of the present invention.

[0031] Figure 1 A structural block diagram of a hysteresis constant voltage power supply circuit 100 provided in an embodiment. The hysteresis constant voltage power supply circuit 100 includes: a start switch unit 110, a first current limiting resistor R1, a hysteresis voltage control unit 120, a second current limiting resistor R2, and an output switch unit 130;

[0032] The first terminal 11 of the start switch unit 110 is used to externally connect to an input power supply voltage and is connected to the first terminal 31 of the output switch unit 130. The second terminal 12 of the start switch unit 110 is connected to the first terminal 21 of the hysteresis voltage control unit 120 through a first current-limiting resistor R1. The third terminal 13 of the start switch unit 110 is connected to one end of a second current-limiting resistor R2;

[0033] The other end of the second current-limiting resistor R2 is respectively connected to the second terminal 22 of the hysteresis voltage control unit 120 and the second terminal 32 of the output switch unit 130. The third terminal 31 of the hysteresis voltage control unit 120 is grounded. The third terminal 33 of the output switch unit 130 is used to output a constant target voltage;

[0034] The hysteresis voltage control unit 120 is used to control the start switch unit 110 and the output switch unit 130 to conduct when the input power supply voltage rises to a first preset voltage threshold, so that the output switch unit 130 outputs a constant target voltage;

[0035] The hysteresis voltage control unit 120 is further used to control the start switch unit 110 and the output switch unit 130 to turn off when the input power supply voltage drops to a second preset voltage threshold, and the second preset voltage threshold is less than the first preset voltage threshold.

[0036] Through the mutual cooperation of the start switch unit 110, the first current-limiting resistor R1, the hysteresis voltage control unit 120, the second current-limiting resistor R2, and the output switch unit 130, the above-mentioned hysteresis voltage power supply circuit 100 immediately starts to output a constant target voltage when the power input voltage reaches the first preset voltage threshold during the voltage climbing process; when the power input voltage is less than the second preset voltage threshold during the voltage drop process, the output is immediately cut off. The above-mentioned hysteresis constant voltage power supply circuit 100 does not need to use a comparison circuit and a logic circuit, and does not need to supply power to the control circuit separately, simplifies the structure of the hysteresis constant voltage power supply circuit, and improves the power quality of the power consumption circuit.

[0037] In one embodiment, as Figure 2 shown, the hysteresis voltage control unit 120 includes a first voltage stabilizing unit 122, a second voltage stabilizing unit 124, and a hysteresis control switch 126;

[0038] One end of the first voltage stabilizing unit 122 is respectively connected to one end of the first current-limiting resistor R1 and the first terminal of the hysteresis control switch 126. The other end of the first voltage stabilizing unit 122 is grounded. The second terminal of the hysteresis control switch 126 is respectively connected to one end of the second current-limiting resistor R2 and the second terminal 32 of the output switch unit 130. One end of the second voltage stabilizing unit 124 is connected to the third terminal of the hysteresis control switch 126. The other end of the second voltage stabilizing unit 124 is grounded;

[0039] Among them, the first voltage regulation value corresponding to the first voltage regulation unit 122 is greater than the second voltage regulation value corresponding to the second voltage regulation unit 124, the first voltage regulation value is less than the first preset voltage threshold, and the second voltage regulation value is less than the second preset voltage threshold.

[0040] In one embodiment, as Figure 2 shown, the first voltage regulation unit 122 uses a first voltage regulation diode, the negative electrode of the first voltage regulation diode is connected to one end of the first current limiting resistor R1 and the first end of the hysteresis control switch 126, and the positive electrode of the first voltage regulation diode is grounded.

[0041] In one embodiment, as Figure 2 shown, the second voltage regulation unit 124 uses a second voltage regulation diode, the negative electrode of the second voltage regulation diode is connected to the third end of the hysteresis control switch 126, and the positive electrode of the second voltage regulation diode is grounded.

[0042] In one embodiment, the hysteresis control switch 126 uses a triode or a MOS transistor.

[0043] In one embodiment, as Figure 2 shown, the hysteresis control switch 126 uses an NPN triode, the collector c of the NPN triode is the first end of the hysteresis control switch 126, the base b of the NPN triode is the second end of the hysteresis control switch 126, and the emitter e of the NPN triode is the third end of the hysteresis control switch 126.

[0044] In one embodiment, as Figure 2 shown, the hysteresis constant voltage power supply circuit 200 further includes an anti-reverse connection unit 140, one end of the anti-reverse connection unit 140 is used to connect to the input power supply voltage, and the other end of the anti-reverse connection unit 140 is respectively connected to the first end 11 of the start switch unit 110 and the first end 31 of the output switch unit 130.

[0045] In one embodiment, as Figure 2 shown, the anti-reverse connection unit 140 uses a diode.

[0046] By providing the anti-reverse connection unit 140, when the input power supply voltage is connected reversely, the circuit is not conducting, the circuit components are not damaged, and the safety of the circuit is improved.

[0047] In one embodiment, the start switch unit 110 uses a triode or a MOS transistor.

[0048] In one embodiment, the output switch unit 130 uses a triode or a MOS transistor, wherein the triode or MOS transistor operates in the amplification state to output a constant target voltage.

[0049] In one embodiment, the output switch unit 130 uses an NPN triode.

[0050] In one embodiment, as Figure 2 shown, the start switch unit 110 uses a PNP triode. The emitter of the PNP triode is the first terminal 11 of the start switch unit 110, the base of the PNP triode is the second terminal 12 of the start switch unit 110, and the collector of the PNP triode is the third terminal 13 of the start switch unit 110.

[0051] In one embodiment, a hysteresis constant voltage power supply is further provided, and the hysteresis constant voltage power supply adopts the above-mentioned hysteresis constant voltage power supply circuit.

[0052] Taking Figure 2 the shown hysteresis constant voltage power supply circuit 200 as an example to illustrate the circuit working process. For the convenience of analysis, the conduction voltage drops of each switching tube are ignored. When the device starts to be powered on, the Vin voltage starts to rise from 0. When it rises to the first preset voltage threshold, the first voltage regulator ZD1 breaks down reversely, and the triode Q1 generates a drive current and conducts. The direction of the drive current is D1 - (Q1b - Q1e) - R1 - ZD1 - GND.

[0053] Further, after the triode Q1 conducts, since the second regulated voltage value of the second voltage regulator ZD2 is less than the first regulated voltage value of the first voltage regulator ZD1, the triode Q2 meets the conduction condition. The branch current flow direction is D1 - (Q1e - Q1c) - R2 - (Q2b - Q2e) - ZD2 - GND. At this time, the upper pin voltage value of the first voltage regulator ZD1 is equal to the second regulated voltage value of the second voltage regulator ZD2, and no current flows through the first voltage regulator ZD1.

[0054] Further, the base voltage of the triode Q3 is the second regulated voltage value of the second voltage regulator ZD2. The current directions are D1 - (Q3c - Q3e) - Vout (main current loop) and D1 - (Q1e - Q1c) - R2 - (Q3b - Q3e) - Vout (drive current). The emitter of the triode Q3 outputs a constant target voltage. When Q1, R1, R2, Q2, ZD2, and Q3 work, they form a constant voltage power supply to output a constant target voltage.

[0055] Among them, when the voltage drops of each switching tube are ignored, the output constant target voltage is equal to the second regulated voltage value of the second voltage regulator.

[0056] Further, when the device is powered off, the Vin voltage gradually drops. When it drops below the second preset voltage threshold, no current flows through the second voltage regulator ZD2. At this time, no current flows through the first voltage regulator ZD1 either. The triodes Q1 and Q2 do not meet the conduction conditions, and the triode Q3 no longer conducts, and the Vout output is directly cut off.

[0057] Among them, the first regulated voltage value corresponding to the first voltage regulator ZD1 is greater than the second regulated voltage value corresponding to the second voltage regulator ZD2, the first preset voltage threshold is greater than the second preset voltage threshold, and when considering the voltage drops of the respective switching tubes, the first preset voltage threshold is greater than the first regulated voltage value, and the second preset voltage threshold is greater than the second regulated voltage value.

[0058] When the power input voltage reaches the first preset voltage threshold during the climbing process of the power input voltage, the above-mentioned hysteresis constant voltage power supply circuit 200 immediately starts to output a constant target voltage; when the power input voltage is less than the second preset voltage threshold during the descending process, the output is immediately cut off. The above-mentioned hysteresis constant voltage power supply circuit 200 does not require the use of a dedicated comparison circuit and a logic circuit, and does not require separate power supply for the control circuit. The circuit is simple, easy to manufacture, and low in cost, simplifies the structure of the hysteresis constant voltage power supply circuit, and improves the power quality of the power consumption circuit.

[0059] The above is only the specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention can easily think of changes or substitutions, which should all be covered within the protection scope of the present invention.

Claims

1. A hysteresis constant voltage power supply circuit, characterized in that, the hysteresis constant voltage power supply circuit includes: a starting switch unit, a first current-limiting resistor, a hysteresis voltage control unit, a second current-limiting resistor and an output switch unit; the first end of the starting switch unit is used for externally connecting an input power supply voltage and is connected to the first end of the output switch unit, the second end of the starting switch unit is connected to the first end of the hysteresis voltage control unit through the first current-limiting resistor, and the third end of the starting switch unit is connected to one end of the second current-limiting resistor; the other end of the second current-limiting resistor is respectively connected to the second end of the hysteresis voltage control unit and the second end of the output switch unit, the third end of the hysteresis voltage control unit is grounded, and the third end of the output switch unit is used for outputting a constant target voltage; the hysteresis voltage control unit is used for controlling the starting switch unit and the output switch unit to conduct when the input power supply voltage rises to a first preset voltage threshold, so that the output switch unit outputs a constant target voltage; the hysteresis voltage control unit is further used for controlling the starting switch unit and the output switch unit to turn off when the input power supply voltage drops to a second preset voltage threshold, and the second preset voltage threshold is less than the first preset voltage threshold; the hysteresis voltage control unit includes a first voltage stabilizing unit, a second voltage stabilizing unit and a hysteresis control switch; one end of the first voltage stabilizing unit is respectively connected to one end of the first current-limiting resistor and the first end of the hysteresis control switch, and the other end of the first voltage stabilizing unit is grounded; the second end of the hysteresis control switch is respectively connected to the other end of the second current-limiting resistor and the second end of the output switch unit, one end of the second voltage stabilizing unit is connected to the third end of the hysteresis control switch, and the other end of the second voltage stabilizing unit is grounded; wherein, the first voltage stabilizing value corresponding to the first voltage stabilizing unit is greater than the second voltage stabilizing value corresponding to the second voltage stabilizing unit, the first voltage stabilizing value is less than the first preset voltage threshold, and the second voltage stabilizing value is less than the second preset voltage threshold.

2. The hysteresis constant voltage power supply circuit according to claim 1, characterized in that, the first voltage stabilizing unit adopts a first voltage stabilizing diode, the negative electrode of the first voltage stabilizing diode is connected to one end of the first current-limiting resistor and the first end of the hysteresis control switch, and the positive electrode of the first voltage stabilizing diode is grounded.

3. The hysteresis constant voltage power supply circuit according to claim 2, characterized in that, the second voltage stabilizing unit adopts a second voltage stabilizing diode, the negative electrode of the second voltage stabilizing diode is connected to the third end of the hysteresis control switch, and the positive electrode of the second voltage stabilizing diode is grounded.

4. The hysteresis constant voltage power supply circuit according to claim 1, characterized in that, the hysteresis control switch adopts a triode or a MOS transistor.

5. The hysteresis constant voltage power supply circuit according to claim 4, characterized in that, The hysteresis control switch uses an NPN transistor. The collector of the NPN transistor is the first end of the hysteresis control switch, the base of the NPN transistor is the second end of the hysteresis control switch, and the emitter of the NPN transistor is the third end of the hysteresis control switch.

6. The hysteresis constant voltage power supply circuit according to claim 1, wherein, the hysteresis constant voltage power supply circuit further includes an anti-reverse connection unit. One end of the anti-reverse connection unit is used to connect to the input power supply voltage, and the other end of the anti-reverse connection unit is respectively connected to the first end of the start switch unit and the first end of the output switch unit.

7. The hysteresis constant voltage power supply circuit according to claim 6, wherein, the anti-reverse connection unit uses a diode.

8. The hysteresis constant voltage power supply circuit according to claim 1, wherein, the start switch unit uses a transistor or a MOS transistor, and the output switch unit uses a transistor or a MOS transistor.

9. The hysteresis constant voltage power supply circuit according to claim 8, wherein, the start switch unit uses a PNP transistor. The emitter of the PNP transistor is the first end of the start switch unit, the base of the PNP transistor is the second end of the start switch unit, and the collector of the PNP transistor is the third end of the start switch unit.

10. A hysteresis constant voltage power supply, wherein, it uses the hysteresis constant voltage power supply circuit according to any one of claims 1 to 9.

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