Circuit for converting positive voltage into negative voltage

Abstract

The utility model discloses a circuit for converting positive voltage into negative voltage, comprising a step-down DC / DC chip module which is connected with an input end of the circuit, receives a continuous positive voltage signal input from the outside, converts the continuous positive voltage signal into a periodic on-off signal and outputs the periodic on-off signal; the rectifying circuit module is respectively connected with the step-down DC / DC chip module and the follow current circuit module, receives signals output by the step-down DC / DC chip module and the follow current circuit module, rectifies the signals and outputs continuous negative voltage signals to a circuit output end; the follow current circuit module is connected with the rectifying circuit module, and outputs a signal to the rectifying circuit module when the step-down DC / DC chip module outputs an open circuit signal; and the feedback loop module is connected with the circuit output end, receives a feedback signal of the circuit output end and outputs the feedback signal to the step-down DC / DC chip module. According to the utility model, the problems of high cost and small output current of the existing circuit for converting positive voltage into negative voltage are solved.

Description

Technical Field

[0001] The utility model belongs to the technical field of electronic circuits, and specifically relates to a positive voltage to negative voltage circuit. Background Art

[0002] The buck DC / DC chip is a highly efficient power management chip, generally used in the positive DC voltage buck circuit, that is, converting a high positive voltage to a low positive voltage. The characteristic of this circuit is that the output voltage is lower than the input voltage. Different voltage values are often used in the field of charging facilities, especially negative voltage. For example, some high-performance power amplifiers require dual power supplies of positive and negative voltages, and the CP circuit part in the charging pile equipment also requires positive and negative voltage supplies.

[0003] Currently, the common method in China is to use a dedicated negative voltage conversion chip to convert positive voltage to negative voltage. However, using a dedicated positive-to-negative voltage chip has the disadvantages of fewer selection types, higher cost, and small output current. Another method is to generate negative voltage using the secondary winding of a transformer. This method is mostly applicable to the case of using a transformer solution, and uses the redundant auxiliary winding of the transformer as the negative voltage output. The disadvantage of this method is that the transformer has a large volume, high cost, and small output current. Summary of the Utility Model

[0004] The technical problem to be solved by the utility model is: to provide a positive voltage to negative voltage circuit to solve the problems of high cost and small output current of the existing positive voltage to negative voltage circuit.

[0005] The technical solution of the utility model is: the utility model provides a positive voltage to negative voltage circuit, including:

[0006] A buck DC / DC chip module, which is connected to the circuit input end, receives the externally input continuous positive voltage signal and converts it into a periodically on-off signal for output;

[0007] A rectifier circuit module, which is respectively connected to the buck DC / DC chip module and the freewheeling circuit module, receives the signals output by the buck DC / DC chip module and the freewheeling circuit module, rectifies them, and outputs a continuous negative voltage signal to the circuit output end;

[0008] A freewheeling circuit module, which is connected to the rectifier circuit module and outputs a signal to the rectifier circuit module when the buck DC / DC chip module outputs an open-circuit signal;

[0009] A feedback loop module, which is connected to the circuit output end, receives the feedback signal from the circuit output end, and outputs the feedback signal to the buck DC / DC chip module.

[0010] Further, the positive voltage to negative voltage circuit based on the buck DC / DC chip further includes a first filtering module and a second filtering module. The first filtering module is respectively connected to the circuit input end and the buck DC / DC chip module, and the second filtering module is respectively connected to the rectification circuit module and the circuit output end. Both the first filtering module and the second filtering module are used to filter high-frequency interference clutter signals.

[0011] Further, the positive voltage to negative voltage circuit based on the buck DC / DC chip further includes an energy storage module. The energy storage module is respectively connected to the circuit output end and the circuit output end, and is used to maintain the stability of the power input.

[0012] Further, the buck DC / DC chip module includes a buck DC / DC chip, a first resistor, and a third capacitor. The first end of the first resistor is connected to the circuit input end, the second end of the first resistor is connected to the enable port of the buck DC / DC chip, one end of the third capacitor is connected to the start capacitor port of the buck DC / DC chip, and the other end is connected to the switch port of the buck DC / DC chip. The ground end of the buck DC / DC chip is connected to the circuit output end, and the input end of the buck DC / DC chip is connected to the circuit input end.

[0013] Further, the rectification circuit module includes an inductor and a fourth capacitor. The first end of the inductor is connected to the switch port of the buck DC / DC chip, the second end of the inductor is connected to the fourth capacitor, the other end of the fourth capacitor is connected to the circuit output end, and the second end of the inductor is grounded.

[0014] Further, the freewheeling circuit module includes a fifth resistor and a diode. The output end of the diode is connected to the first end of the inductor, the input end of the diode is connected to the circuit output end, one end of the fifth resistor is connected to the circuit output end, and the other end of the fifth resistor is connected to the second end of the inductor.

[0015] Further, the feedback loop module includes a second resistor, a third resistor, and a fourth resistor. The first end of the second resistor is connected to the feedback end of the buck DC / DC chip, the second end of the second resistor is respectively connected to the ground end of the buck DC / DC chip and the input end of the diode. The third resistor and the fourth resistor are connected in series. The third resistor is connected to the feedback end of the buck DC / DC chip, and the fourth resistor is grounded.

[0016] Further, the first filtering module includes a second capacitor. One end of the second capacitor is connected to the circuit input terminal, and the other end of the second capacitor is grounded.

[0017] Further, the second filtering module includes a fifth capacitor. One end of the fifth capacitor is connected to the circuit output terminal, and the other end of the fifth capacitor is grounded.

[0018] Further, the energy storage module includes a first capacitor. The first capacitor is respectively connected to the input terminal and the output terminal of the circuit

[0019] The beneficial effects of the present utility model are as follows: The present utility model uses a buck DC / DC chip and capacitors, inductors, diodes, and resistors to form a positive voltage to negative voltage circuit. There is a rich variety of buck DC / DC chips to choose from, and the selection is easy. The circuit has a simple structure, low cost, and small occupied area. The output current capacity of the negative voltage depends on the rated output current of the buck DC / DC chip, and the rated output current of this chip is greater than the rated output current of the negative voltage conversion chip. Therefore, the positive voltage to negative voltage circuit composed of this chip has a larger output current. Description of the Drawings

[0020] In order to make the objectives, technical solutions, and advantages of the present utility model clearer, the present utility model will be further described in detail below with reference to the drawings and specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present utility model and are not used to limit the present utility model.

[0021] In order to make the description of the present disclosure more detailed and complete, the following provides an illustrative description of the embodiments and specific examples of the present utility model; however, this is not the only form for implementing or using the specific examples of the present utility model. The embodiments cover the features of multiple specific examples and the method steps and their sequences for constructing and operating these specific examples. However, other specific examples can also be used to achieve the same or equivalent functions and step sequences. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of this application.

[0022] It should be noted that the terms "first", "second", etc. in the specification and claims of the present utility model and the above drawings are used to distinguish similar objects and do not necessarily need to describe a specific order or sequence. It should be understood that such data can be interchanged under appropriate circumstances so that the embodiments of the present utility model described here can be implemented in an order other than those illustrated or described here.

[0023] Figure 1 Schematic diagram of the positive voltage to negative voltage circuit module provided by the embodiment of this application;

[0024] Figure 2 This is the circuit structure diagram of the positive voltage to negative voltage circuit provided by the embodiment of the present application.

[0025] Description of the reference numerals:

[0026] 1 - Buck DC / DC chip module, 2 - Rectifier circuit module, 3 - Freewheeling circuit module, 4 - Feedback loop module, 5 - First filtering module, 6 - Second filtering module, 7 - Energy storage module;

[0027] 11 - Buck DC / DC chip, 12 - First resistor, 13 - Third capacitor, 21 - Inductor, 22 - Fourth capacitor, 31 - Diode, 32 - Fifth resistor, 41 - Second resistor, 42 - Third resistor, 43 - Fourth resistor, 51 - Second capacitor, 61 - Fifth capacitor, 71 - First capacitor. Detailed implementation manners

[0028] In order to enable those skilled in the art to better understand the solution of the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative efforts belong to the scope of protection of the present application.

[0029] In the embodiments of the present application, it should be noted that in this text, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations.

[0030] It should be pointed out that the "connection" in the embodiments of the present application can be understood as an electrical connection, and the connection of two electrical components can be a direct or indirect connection between two electrical components. For example, when A is connected to B, it can be either a direct connection between A and B or an indirect connection between A and B through one or more other electrical components.

[0031] The embodiments of the present application provide a positive voltage to negative voltage circuit. Figure 1 This is the schematic diagram of the positive voltage to negative voltage circuit module provided by the embodiment of the present application. As Figure 1 shown, the circuit includes a buck DC / DC chip module 1, a rectifier circuit module 2, a freewheeling circuit module 3, a feedback loop module 4, a first filtering module 5, a second filtering module 6, and an energy storage module 7.

[0032] The buck DC / DC chip module 1 receives the continuous positive high-voltage signal input at the circuit input end and outputs a periodically on-off positive low-voltage signal to the rectification circuit module 2. The buck DC / DC chip module 1 is used to create a voltage difference between the output voltage and the input voltage, convert the input positive high-voltage signal into a low positive voltage signal, and at the same time convert the input continuous signal into a periodically on-off signal for output. The freewheeling circuit module 3 is connected to the rectification circuit module 2 and outputs a signal to the rectification circuit module 2 when the output of the buck DC / DC chip module 1 is open. The rectification circuit module 2 is connected to the freewheeling circuit module 3 and the buck DC / DC chip module 1, and is used to integrate the periodically on-off signal and the signal output by the freewheeling circuit into a continuous negative voltage signal and output the signal to the power output end. The feedback circuit module 4 is connected to the power output end, receives the feedback signal output by the circuit output end, and outputs the feedback signal to the buck DC / DC chip module 1. The feedback circuit module 4 is used to monitor the voltage of the output signal and feedback it to the buck DC / DC chip module 1. The buck DC / DC chip module 1 adjusts the voltage difference between the output signal and the input signal according to the feedback signal, so as to stably output the preset negative voltage signal.

[0033] Preferably, the positive voltage to negative voltage circuit further includes a first filtering module 5 and a second filtering module 6. The first filtering module 5 is respectively connected to the circuit input end and the buck DC / DC chip module 1, and the second filtering module 6 is respectively connected to the circuit output end and the rectification circuit module 2, providing a low-impedance loop for high-frequency interference at the circuit input end and output end, and improving the stability of the circuit.

[0034] The positive voltage to negative voltage circuit further includes an energy storage module 7. The energy storage module 7 is respectively connected to the output end and the input end of the circuit. This module is used for energy storage to improve the stability of the circuit input power supply.

[0035] Figure 2 For the circuit structure diagram of the positive voltage to negative voltage circuit provided by the embodiment of the present application, as Figure 2 shown, the buck DC / DC chip module 1 includes a buck DC / DC chip 11, a first resistor 12, and a third capacitor 13. One end of the first resistor 12 is connected to the circuit input end, and the other end is connected to the enable port of the buck DC / DC chip 11. The first resistor 12 is a current-limiting resistor, which is used to provide voltage and a small current to the buck DC / DC chip 11 to enable the chip to work normally. One end of the third capacitor 13 is connected to the switch port SW of the buck DC / DC chip 11, and the other end is connected to the boost capacitor port CB. The third capacitor 13 is a bootstrap capacitor, which is used for the conduction of the high-side MOS transistor inside the buck DC / DC chip 11, and the buck DC / DC chip 11 outputs a periodically on-off signal.

[0036] The rectifier circuit module 2 includes an inductor 21 and a fourth capacitor 22. One end of the inductor 21 is connected to the switch port of the buck DC / DC chip 11, and the other end is connected to the fourth capacitor 22. The other end of the fourth capacitor 22 is connected to the circuit output terminal to output the rectified continuous negative voltage signal. The connection end of the inductor 21 and the fourth capacitor 22 is grounded as the reference zero-potential voltage.

[0037] The freewheeling circuit module 3 includes a fifth resistor 31 and a diode 32. The output terminal of the diode 32 is connected to one end of the inductor 21, and the input terminal of the diode 32 is connected to the circuit output terminal. One end of the fifth resistor 31 is connected to the circuit output terminal, and the other end of the fifth resistor 31 is connected to the inductor 21. When the output of the buck DC / DC chip 11 is open, the inductor 21, the fifth resistor 31, and the diode 32 form a loop, and the inductor 21 forms an induced current, which passes through the fourth capacitor 22 and is output to the circuit output terminal, thereby ensuring the continuity of the output signal.

[0038] The feedback loop module 4 includes a second resistor 41, a third resistor 42, and a fourth resistor 43. One end of the second resistor 41 is connected to the feedback terminal FB of the buck DC / DC chip 11, and the other end of the second resistor 41 is respectively connected to the ground terminal GND of the buck DC / DC chip 11 and the input terminal of the diode. The third resistor 42 and the fourth resistor 43 are connected in series. The third resistor 42 is connected to the feedback terminal FB of the buck DC / DC chip 11, and the fourth resistor 43 is grounded. The second resistor 41 forms a voltage division with the third resistor 42 and the fourth resistor 43 to detect the voltage at the circuit input terminal, and the negative voltage value output at the circuit output terminal is adjusted by adjusting the resistance values of the second resistor 41, the third resistor 42, and the fourth resistor 43.

[0039] The first filtering module 5 includes a second capacitor 51, and the second filtering module includes a fifth capacitor 61. One end of the second capacitor 51 is connected to the circuit input terminal, and the other end is grounded. One end of the fifth capacitor 61 is grounded, and the other end is connected to the circuit output terminal. The second capacitor 51 and the fifth capacitor 61 are both filtering capacitors for filtering out the clutter generated by high-frequency interference.

[0040] The energy storage module 7 includes a first capacitor 71, and the first capacitor 71 is respectively connected to the circuit input terminal and the circuit output terminal to maintain the stability of the power input.

[0041] The above content is a further detailed description of the present application in combination with specific implementation manners. It cannot be determined that the specific implementation of the present application is only limited to these descriptions. For those of ordinary skill in the technical field to which the present application belongs, without departing from the concept of the present application, several simple deductions or substitutions can still be made, which should all be regarded as the protection scope of the present application.

Claims

1. A positive voltage to negative voltage conversion circuit, characterized in that: include: A step-down DC / DC chip module, which is connected to the circuit input terminal, receives a continuous positive voltage signal from an external input and converts it into a periodic on-off signal output; A rectifier circuit module, the rectifier circuit module is connected to the step-down DC / DC chip module and the freewheeling circuit module respectively, receives the signals output by the step-down DC / DC chip module and the freewheeling circuit module, performs rectification, and outputs a continuous negative voltage signal to the circuit output end; A freewheeling circuit module, the freewheeling circuit module is connected to the rectifier circuit module, and outputs a signal to the rectifier circuit module when the step-down DC / DC chip module outputs a disconnection signal; A feedback loop module is connected to the circuit output end, receives a feedback signal from the circuit output end, and outputs the feedback signal to the step-down DC / DC chip module.

2. A positive voltage to negative voltage conversion circuit as claimed in claim 1, characterized in that: The positive voltage to negative voltage circuit based on the step-down DC / DC chip also includes a first filtering module and a second filtering module, the first filtering module is respectively connected to the circuit input end and the step-down DC / DC chip module, the second filtering module is respectively connected to the rectifier circuit module and the circuit output end, and the first filtering module and the second filtering module are both used to filter high-frequency interference clutter signals.

3. A positive voltage to negative voltage conversion circuit as claimed in claim 1, characterized in that: The positive voltage to negative voltage circuit based on the step-down DC / DC chip also includes an energy storage module, which is respectively connected to the circuit output end and the circuit output end to maintain the stability of the power input.

4. A positive voltage to negative voltage conversion circuit as claimed in claim 1, characterized in that: The step-down DC / DC chip module includes a step-down DC / DC chip, a first resistor and a third capacitor, wherein a first end of the first resistor is connected to the circuit input end, a second end of the first resistor is connected to the enable port of the step-down DC / DC chip, one end of the third capacitor is connected to the start capacitor port of the step-down DC / DC chip, and the other end is connected to the switch port of the step-down DC / DC chip, a ground end of the step-down DC / DC chip is connected to the circuit output end, and an input end of the step-down DC / DC chip is connected to the circuit input end.

5. A positive voltage to negative voltage conversion circuit as claimed in claim 4, characterized in that: The rectifier circuit module includes an inductor and a fourth capacitor, a first end of the inductor is connected to the switch port of the step-down DC / DC chip, a second end of the inductor is connected to the fourth capacitor, the other end of the fourth capacitor is connected to the circuit output end, and a second end of the inductor is grounded.

6. A positive voltage to negative voltage conversion circuit as claimed in claim 5, characterized in that: The freewheeling circuit module includes a fifth resistor and a diode, the output end of the diode is connected to the first end of the inductor, the input end of the diode is connected to the circuit output end, one end of the fifth resistor is connected to the circuit output end, and the other end of the fifth resistor is connected to the second end of the inductor.

7. A positive voltage to negative voltage conversion circuit as claimed in claim 6, characterized in that: The feedback loop module includes a second resistor, a third resistor and a fourth resistor, wherein a first end of the second resistor is connected to a feedback end of the step-down DC / DC chip, a second end of the second resistor is respectively connected to a ground end of the step-down DC / DC chip and an input end of the diode, the third resistor and the fourth resistor are connected in series, the third resistor is connected to the feedback end of the step-down DC / DC chip, and the fourth resistor is grounded.

8. A positive voltage to negative voltage conversion circuit as claimed in claim 2, characterized in that: The first filtering module includes a second capacitor, one end of the second capacitor is connected to the circuit input end, and the other end of the second capacitor is grounded.

9. A positive voltage to negative voltage conversion circuit as claimed in claim 2, characterized in that: The second filtering module includes a fifth capacitor, one end of the fifth capacitor is connected to the circuit output end, and the other end of the fifth capacitor is grounded.

10. The positive voltage to negative voltage conversion circuit as claimed in claim 3, characterized in that: The energy storage module includes a first capacitor, and the first capacitor is connected to the input end of the circuit and the output end of the circuit respectively.

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