Power supply circuit with adjustable voltage

Abstract

The utility model discloses a voltage-adjustable power supply circuit, comprising a power supply which provides a 5V voltage, a power supply management circuit which comprises a PT1502EQFN chip and a peripheral circuit of the PT1502EQFN chip; a pin 12 of the PT1502EQFN chip is electrically connected with the power supply; the voltage regulation circuit comprises a switch control circuit and a feedback circuit; the input end of the switch circuit is connected with an external control end, the output end of the switch control circuit is electrically connected with the input end of the feedback circuit, and one output end of the feedback circuit is electrically connected with the pin 6 of the PT1502EQFN chip.

Description

Technical Field

[0001] The utility model relates to the field of voltage-adjustable power supply circuits, and in particular to a voltage-adjustable power supply circuit. Background Art

[0002] Most of the current power supplies are fixed-type power supply circuits, that is, the output voltage of the power supply circuit is fixed. However, with the continuous development of the power supply industry, the output voltage of the power supply is also different, and there is also a requirement for automatic adjustment of the output voltage.

[0003] Therefore, the existing technology has defects and needs to be improved. Summary of the Invention

[0004] The technical problem to be solved by the utility model is to provide a power supply circuit with adjustable voltage, which adjusts the output voltage by changing the resistance value of a feedback resistor.

[0005] The technical solution of the utility model is as follows: a voltage-adjustable power supply circuit, comprising:

[0006] Power supply, which provides 5V voltage:

[0007] A power management circuit, comprising a PT1502EQFN chip and its peripheral circuits; pin 12 of the PT1502EQFN chip being electrically connected to a power source;

[0008] A voltage regulation circuit, comprising: a switch control circuit and a feedback circuit; an input end of the switch circuit is connected to an external control end, an output end of the switch control circuit is electrically connected to an input end of the feedback circuit, and an output end of the feedback circuit is electrically connected to pin 6 of a PT1502EQFN chip;

[0009] The voltage output terminal VDD12 is electrically connected to another output terminal of the feedback circuit and is electrically connected to pin 10 of the PT1502EQFN chip via an inductor L1.

[0010] Applied to the above technical solution, the feedback circuit includes a resistor R15 and a resistor R17; the resistor R15 and the resistor R17 are connected in series, and the common connection point of the resistor R15 and the resistor R17 is electrically connected to pin 6 of the PT1502EQFN chip and the output end of the switching circuit respectively; the other end of the resistor R15 is electrically connected to one end of the inductor L1 and the voltage output end VDD12 respectively; the other end of the resistor R17 is grounded.

[0011] Applied to each of the above technical solutions, the switching circuit includes a resistor R18 and a transistor Q1; the collector of the transistor is electrically connected to the common connection point of the resistor R15 and the resistor R17 via the resistor R18; the emitter of the transistor Q1 is grounded, and the base of the transistor Q1 is connected to the external control terminal.

[0012] Applied to each of the above technical solutions, the voltage-adjustable power supply circuit further includes a capacitor C37 , one end of the capacitor C37 is electrically connected to the voltage output terminal VDD12 , and the other end of the capacitor C37 is electrically connected to the resistor R18 .

[0013] Applied to each of the above technical solutions, the voltage-adjustable power supply circuit further includes a filter circuit, and the filter circuit is provided at the voltage output terminal VDD12.

[0014] Applied to the above-mentioned technical solutions, the filtering circuit includes a capacitor C38 and a capacitor C39; the capacitor C38 and the capacitor C39 are connected in parallel, a common connection end of the capacitor C38 and the capacitor C39 is connected to the voltage output end VDD12, and the other common connection end of the capacitor C38 and the capacitor C39 is grounded.

[0015] The beneficial effects of the present invention are as follows: when the power supply input is 5V, the PT1502EQFN chip works, and the PT1502EQFN chip outputs voltage to the output terminal VDD12. When the input of the output terminal VDD12 is adjusted, the voltage change of the feedback circuit is controlled by the switching circuit to adjust the voltage of the output terminal VDD12. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a schematic diagram of the power supply circuit of the utility model. DETAILED DESCRIPTION

[0017] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0018] like Figure 1 As shown: This embodiment provides a voltage-adjustable power supply circuit, a power supply, and the power supply provides a 5V voltage:

[0019] A power management circuit, comprising a PT1502EQFN chip and its peripheral circuits; pin 12 of the PT1502EQFN chip being electrically connected to a power source;

[0020] A voltage regulation circuit, comprising: a switch control circuit and a feedback circuit; an input end of the switch circuit is connected to an external control end, an output end of the switch control circuit is electrically connected to an input end of the feedback circuit, and an output end of the feedback circuit is electrically connected to pin 6 of a PT1502EQFN chip;

[0021] a voltage output terminal VDD12, which is electrically connected to another output terminal of the feedback circuit and electrically connected to pin 10 of the PT1502EQFN chip via an inductor L1;

[0022] Among them, when the power input is 5V, the PT1502EQFN chip works, and the PT1502EQFN chip outputs voltage to the output terminal VDD12. When the input of the output terminal VDD12 is adjusted, the voltage change of the feedback circuit is controlled by the switching circuit to adjust the voltage of the output terminal VDD12.

[0023] In this embodiment, if Figure 1 As shown: the feedback circuit includes a resistor R15 and a resistor R17; the resistor R15 and the resistor R17 are connected in series, and the common connection point of the resistor R15 and the resistor R17 is electrically connected to pin 6 of the PT1502EQFN chip and the output end of the switch circuit respectively; the other end of the resistor R15 is electrically connected to one end of the inductor L1 and the voltage output end VDD12 respectively; the other end of the resistor R17 is grounded; the switch circuit includes a resistor R18 and a transistor Q1; the collector of the transistor is electrically connected to the common connection point of the resistor R15 and the resistor R17 via the resistor R18; the emitter of the transistor Q1 is grounded, and the base of the transistor Q1 is connected to the external control end;

[0024] Among them, when the power input is 5V and the PT1502EQFN chip is working, when the base of the transistor Q1 is at a low level, the transistor Q1 is cut off, and the 6-pin of the PT1502EQFN chip outputs 0.6V. This 0.6V is the fixed feedback voltage V of the PT1502EQFN. fb ,

[0025] Right now: Then we have:

[0026]

[0027] When the power input is 5V and the PT1502EQFN chip is working, when the base of transistor Q1 is high, transistor Q1 is turned on, and resistor R18 is connected as a feedback resistor and connected in parallel with resistor R17. The feedback voltage V fb The corresponding formula becomes:

[0028] Right now:

[0029] The voltage at the voltage output terminal VDD12 is:

[0030]

[0031] From the above, it can be seen that the voltage output terminal VDD12 is adjusted by whether the transistor Q1 is turned on or closed.

[0032] In this embodiment, if Figure 1 As shown: the voltage-adjustable power supply circuit further includes a capacitor C37, one end of the capacitor C37 is electrically connected to the voltage output terminal VDD12, and the other end of the capacitor C37 is electrically connected to the resistor R18;

[0033] Among them, capacitor 37 is a feedforward capacitor, the purpose of which is to adjust the response speed of the output voltage of the PT1502EQFN chip.

[0034] In this embodiment, if Figure 1 As shown: the voltage-adjustable power supply circuit further includes a filter circuit, which is provided at the voltage output terminal VDD12; the filter circuit includes a capacitor C38 and a capacitor C39; the capacitor C38 and the capacitor C39 are connected in parallel, a common connection terminal of the capacitor C38 and the capacitor C39 is connected to the voltage output terminal VDD12, and the other common connection terminal of the capacitor C38 and the capacitor C39 is grounded;

[0035] Among them, the capacitor C38 and the capacitor C39 are the pre-filter circuit of the voltage output terminal VDD12, which filters out interference signals from the input voltage of the voltage output terminal VDD12, that is, outputs a stable voltage.

[0036] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A voltage-adjustable power supply circuit, characterized in that: include: Power supply, which provides 5V voltage: A power management circuit, comprising a PT1502EQFN chip and its peripheral circuits; pin 12 of the PT1502EQFN chip being electrically connected to a power source; A voltage regulation circuit, comprising: a switch control circuit and a feedback circuit; an input terminal of the switch control circuit is connected to an external control terminal, an output terminal of the switch control circuit is electrically connected to an input terminal of the feedback circuit, and an output terminal of the feedback circuit is electrically connected to pin 6 of a PT1502EQFN chip; The voltage output terminal VDD12 is electrically connected to another output terminal of the feedback circuit and is electrically connected to pin 10 of the PT1502EQFN chip via an inductor L1.

2. The voltage-adjustable power supply circuit according to claim 1, wherein: The feedback circuit includes a resistor R15 and a resistor R17; the resistor R15 and the resistor R17 are connected in series, and the common connection point of the resistor R15 and the resistor R17 is electrically connected to pin 6 of the PT1502EQFN chip and the output end of the switching circuit respectively; the other end of the resistor R15 is electrically connected to one end of the inductor L1 and the voltage output end VDD12 respectively; the other end of the resistor R17 is grounded.

3. The voltage-adjustable power supply circuit according to claim 2, wherein: The switching circuit includes a resistor R18 and a transistor Q1; the collector of the transistor is electrically connected to a common connection point of the resistor R15 and the resistor R17 via the resistor R18; the emitter of the transistor Q1 is grounded, and the base of the transistor Q1 is connected to an external control terminal.

4. The voltage-adjustable power supply circuit according to claim 1, wherein: The voltage-adjustable power supply circuit further includes a capacitor C37 , one end of the capacitor C37 is electrically connected to the voltage output terminal VDD12 , and the other end of the capacitor C37 is electrically connected to the resistor R18 .

5. The voltage-adjustable power supply circuit according to claim 1, wherein: The voltage-adjustable power supply circuit further includes a filter circuit, which is provided at the voltage output terminal VDD12.

6. The voltage-adjustable power supply circuit according to claim 5, wherein: The filter circuit includes a capacitor C38 and a capacitor C39; the capacitor C38 and the capacitor C39 are connected in parallel, a common connection end of the capacitor C38 and the capacitor C39 is connected to the voltage output end VDD12, and the other common connection end of the capacitor C38 and the capacitor C39 is grounded.

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