CN218473030U

CN218473030U - Voltage conversion circuit

Info

Publication number: CN218473030U
Application number: CN202222771174.0U
Authority: CN
Inventors: 张慕生
Original assignee: Shencun Technology Wuxi Co ltd
Current assignee: Shencun Technology Wuxi Co ltd
Priority date: 2022-10-20
Filing date: 2022-10-20
Publication date: 2023-02-10
Anticipated expiration: 2032-10-20

Abstract

The utility model relates to the technical field of voltage conversion, and discloses a voltage conversion circuit, which comprises a DC-DC conversion module, a voltage feedback module, an adjusting resistor and an adjusting voltage generation module; the DC-DC conversion module comprises a voltage output end and a voltage feedback end, and the voltage feedback module comprises an input end and a feedback voltage output end; the voltage output end is electrically connected with the input end, and the feedback voltage output end is electrically connected with the voltage feedback end; the regulated voltage generation module comprises a regulated voltage output end which is electrically connected with the voltage feedback end through the regulating resistor, and when the regulated voltage generation module is in actual use, the output voltage of the DC-DC conversion module can be adjusted through the regulating resistor and the regulated voltage generation module without changing the resistance value of the feedback resistor, so that the regulated voltage generation module is beneficial to actual application.

Description

Voltage conversion circuit

Technical Field

The utility model relates to a voltage conversion technology field, concretely relates to voltage conversion circuit.

Background

In electronic products, a voltage conversion circuit is often required to perform voltage conversion to obtain a proper power voltage. The voltage conversion circuit can be divided into a rectification circuit, an inverter circuit and a DC-DC conversion circuit according to the difference of voltage input and voltage output, wherein the DC-DC conversion circuit can be divided into a boost DC-DC conversion circuit, a buck DC-DC conversion circuit and a buck-boost DC-DC conversion circuit according to the relation of the magnitude of the input voltage and the magnitude of the output voltage.

For the step-down DC-DC conversion circuit, most of the output voltages of the step-down DC-DC conversion circuit are fixed values, and the output voltages are input to the feedback voltage input end of the DC-DC conversion circuit through the feedback resistor, for example, as shown in fig. 1, the circuit includes a chip of model number TPS61230, and the output voltage VOUT = (1 + R1/R2) × VREF, where VOUT is the output voltage, R1 and R2 are the resistance values of the feedback resistor, and VREF is the internal reference voltage of the chip is not adjustable. If the output voltage needs to be changed, the feedback resistor on the actual circuit board needs to be manually changed, namely the feedback resistor on the circuit board is firstly removed and then is soldered again. This approach is not practical for most application scenarios.

In addition, for some PMIC chips with programmable output voltage, although the output voltage can be changed by programming, the following defects exist in practical use: firstly, the PIMC chip is expensive, and the similar chip is short in supply and demand; secondly, the voltage regulation precision is low, and the voltage regulation is mostly carried out by stepping regulation more than 50 mv; in addition, the adjustable range of the output voltage is narrow, and is usually within 3.3V; and finally, the application field is narrow, and the power supply device can be generally only applied to the power supply of chips such as an FPGA (field programmable gate array) and an SOC (system on chip).

SUMMERY OF THE UTILITY MODEL

In view of the deficiencies of the background art, the present invention provides a voltage converting circuit capable of adjusting an output voltage of a DC-DC converter circuit without replacing a feedback resistor when a PMIC chip is not used.

For solving the technical problem, the utility model provides a following technical scheme: a voltage conversion circuit comprises a DC-DC conversion module, a voltage feedback module, a regulating resistor and a regulating voltage generation module;

the DC-DC conversion module comprises a voltage output end and a voltage feedback end, and the voltage feedback module comprises an input end and a feedback voltage output end; the voltage output end is electrically connected with the input end, and the feedback voltage output end is electrically connected with the voltage feedback end; the regulated voltage generation module includes a regulated voltage output electrically connected to the voltage feedback terminal through the regulating resistor, the regulated voltage generation module configured to provide a regulated voltage to the regulating resistor.

In a certain embodiment, the voltage feedback module includes a first resistor and a second resistor, one end of the first resistor is an input end of the voltage feedback module and is electrically connected to the voltage output end, the other end of the first resistor is a feedback voltage output end of the voltage feedback module and is electrically connected to the voltage feedback end and one end of the second resistor, respectively, and the other end of the second resistor is grounded.

As a further technical solution, the adjusting voltage generating module includes a control unit, a digital-to-analog converting unit and an amplifying unit, the control unit is electrically connected to the digital-to-analog converting unit and configured to provide a digital signal to the digital-to-analog converting unit, the digital-to-analog converting unit converts the input digital signal into an analog signal, an analog signal output end of the digital-to-analog converting unit is electrically connected to an input end of the amplifying unit, and an output end of the amplifying unit is electrically connected to the adjusting resistor.

Furthermore, the regulated voltage generating module further includes a reference voltage generating unit electrically connected to the digital-to-analog converting unit and configured to provide a reference voltage to the digital-to-analog converting unit.

Specifically, the control unit comprises a single chip microcomputer with the model number of STM32L476RGT 6; the digital-to-analog conversion unit comprises a digital-to-analog conversion chip with the model number of DAC7578 SPWR; the amplifying unit comprises an amplifying chip with the model of LM 358D; the reference voltage generating unit comprises a power supply chip with the model number of REF3030 AIDBZR.

As a further technical solution, the adjusting voltage generating module includes a second control unit and an amplifying unit, the second control unit is electrically connected to an input end of the amplifying unit and configured to provide an analog voltage to the input end of the amplifying unit, and an output end of the amplifying unit is electrically connected to the adjusting resistor.

To the working principle of the circuit of the utility model is explained: firstly, it is to be understood that, for each DC-DC conversion module, the voltage at the voltage feedback end is fixed, assuming that the current flowing from the voltage output end to the voltage feedback end is I1, the current flowing from the voltage output end to the voltage feedback end through the regulating resistor is I3, and the current flowing from the voltage feedback end to the ground end is I2, according to kirchhoff current law, I2= I1+ I3, when I2 is kept unchanged (I2 is actually the voltage at the voltage feedback end divided by the resistance value of the second resistor), the magnitude of the current I1 can be changed by changing the magnitude of the current I3, and the change of the current I3 can be realized by adjusting the magnitude of the voltage input to the regulating resistor; therefore, the output voltage of the DC-DC conversion circuit can be adjusted by changing the output voltage of the regulating voltage generating module.

Compared with the prior art, the utility model the beneficial effect who has is: firstly, the output voltage of the DC-DC conversion module can be adjusted only by adding an adjusting resistor and an adjusting voltage generating module on the basis of the existing DC-DC conversion module without changing the resistance value of a feedback resistor, thereby being beneficial to practical application; in addition, compared with the PIMC chip, the output voltage regulation of the DC-DC conversion module with higher precision can be realized only by continuously changing the regulation voltage output by the regulation voltage generation module, the output voltage regulation range of the DC-DC conversion module is based on the voltage range input to the regulation resistor, and the voltage range input to the regulation resistor is limited slightly, so that the output voltage regulation range is large, and the application field is wide.

Drawings

Fig. 1 is a circuit diagram of a conventional DC-DC converter circuit;

FIG. 2 is a schematic structural view of the present invention;

fig. 3 is a first schematic structural diagram of a regulation generation module according to the present invention;

fig. 4 is a circuit diagram of a control unit of the present invention;

fig. 5 is a circuit diagram of the digital-to-analog signal conversion unit of the present invention;

FIG. 6 is a circuit diagram of an amplifying unit according to the present invention;

fig. 7 is a first structural diagram of a conditioning generation module according to the present invention;

fig. 8 is a schematic diagram of the circuit of fig. 1 according to the present invention.

Detailed Description

The present invention will now be described in further detail with reference to the accompanying drawings. These drawings are simplified schematic drawings and illustrate the basic structure of the present invention only in a schematic manner, and thus show only the components related to the present invention.

As shown in fig. 2, a voltage conversion circuit includes a DC-DC conversion module 1, a voltage feedback module 2, a regulating resistor R5, and a regulating voltage generation module 3;

the DC-DC conversion module 1 comprises a voltage output end OT1 and a voltage feedback end IN2, and the voltage feedback module 2 comprises an input end IN1 and a feedback voltage output end OT2; the voltage output end OT1 is electrically connected with the input end IN1, and the feedback voltage output end OT2 is electrically connected with the voltage feedback end IN 1; the regulated voltage generating module 3 includes a regulated voltage output terminal OT3, the regulated voltage output terminal OT3 is electrically connected to the voltage feedback terminal IN2 through a regulating resistor R5, and the regulated voltage generating module 3 is configured to provide a regulated voltage to the regulating resistor R5.

Right the working principle of the circuit of the utility model is explained: firstly, it is to be noted that, for each DC-DC conversion module 1, the voltage of the voltage feedback terminal IN2 is fixed, assuming that the current flowing from the voltage output terminal OT1 to the voltage feedback terminal IN2 is I1, the current flowing from the voltage output terminal OT3 to the voltage feedback terminal IN2 through the adjusting resistor R5 is I3, and the current flowing from the voltage feedback terminal IN2 to the ground terminal is I2, according to kirchhoff current law, I2= I1+ I3, when I2 is kept unchanged (I2 is actually the voltage of the voltage feedback terminal IN2 divided by the resistance of the second resistor), the size of the current I1 can be changed by changing the size of the current I3, and the change of the current I3 can be implemented by adjusting the size of the voltage input to the adjusting resistor R5; therefore, the output voltage of the DC-DC conversion circuit can be adjusted by changing the output voltage of the regulated voltage generation module 3.

IN this embodiment, the voltage feedback module 2 is an existing resistor, taking fig. 1 as an example, the voltage feedback module 2 includes a first resistor R1 and a second resistor R2, one end of the first resistor R1 is an input terminal IN1 of the voltage feedback module 2 and is electrically connected to the voltage output terminal OT1, the other end of the first resistor R1 is a feedback voltage output terminal OT2 of the voltage feedback module 2 and is electrically connected to the voltage feedback terminal IN2 and one end of the second resistor R2, respectively, and the other end of the second resistor R2 is grounded.

As shown in fig. 3, in this embodiment, the adjusting voltage generating module 3 includes a control unit 30, a digital-to-analog converting unit 31, an amplifying unit 32 and a reference voltage generating unit 33, the control unit 30 is electrically connected to the digital-to-analog converting unit 31 and configured to provide a digital signal to the digital-to-analog converting unit 31, the digital-to-analog converting unit 31 converts the input digital signal into an analog signal, an analog signal output end of the digital-to-analog converting unit 31 is electrically connected to an input end of the amplifying unit, and an output end of the amplifying unit is electrically connected to the adjusting resistor R5; the reference voltage generating unit 33 is electrically connected to the digital-to-analog converting unit 31, and is configured to provide a reference voltage to the digital-to-analog converting unit 31.

As shown in fig. 4, 5, 6, and 7, in this embodiment, the control unit 30 includes a single chip microcomputer of a model STM32L476RGT 6; the digital-to-analog conversion unit 31 comprises a digital-to-analog conversion chip with the model of DAC7578 SPWR; the amplifying unit 32 comprises an amplifying chip with the model LM 358D; the reference voltage generating unit 33 includes a power supply chip of a model REF3030 AIDBZR.

When the system is actually used, different models of single-chip microcomputers can be selected based on actual requirements such as the running speed of the single-chip microcomputers, the range of output digital voltages and the like; can select the digital-to-analog conversion chip of different models based on the conversion speed and conversion precision of the digital-to-analog conversion unit, wherein the higher the conversion precision of the digital-to-analog conversion unit 31 is, the higher the adjustment precision of the utility model is; different types of power chips may be selected according to the amplification factor of the amplification unit 32 and the driving capability of the output voltage.

In actual use, some single-chip microcomputers or other control chips can directly output analog voltages, so as shown in fig. 7, in a certain embodiment, the regulated voltage generating module 3 includes a second control unit 34 and an amplifying unit 32, the second control unit 34 is electrically connected to an input terminal of the amplifying unit 32 and configured to provide the analog voltages to the input terminal of the amplifying unit 32, an output terminal of the amplifying unit 32 is electrically connected to the regulating resistor R5, and the digital-to-analog converting unit 31 and the reference voltage generating unit 32 are not required in the regulated voltage generating module 3 shown in fig. 7.

Taking the DC-DC conversion module 1 shown in fig. 1 as an example, as shown in fig. 8, the output voltage of the DC-DC conversion circuit is VOUT, the voltage at the voltage feedback end is VREF, the voltage input to the regulating resistor R5 by the regulating voltage generation module 3 is G × VDAC, G is the amplification factor of the amplification unit 32, VDAC is the analog voltage output by the digital-to-analog conversion unit 31, and according to kirchhoff voltage law, the following can be obtained:

I1+I3＝I2；

and I1= (VOUT-VREF)/R1; i2= VREF/R2; i3= (G × VDAC — VREF)/R5; then the

(VOUT-VREF)/R1 + (G × VDAC-VREF)/R5 = VREF/R2; finally obtaining

VOUT＝((R1*R5*VREF-R1*R2*(G*VDAC-VREF))/R2*R5)+VREF；

Because R1, R2, R5, VREF, and G are all quantitative, and VDAC output is a variable, the magnitude of the output voltage of the DC-DC conversion module 1 can be adjusted by changing the magnitude of the analog voltage output by the digital-to-analog conversion unit 31.

Assuming that the resistance of the first resistor R1 is 107K, the resistance of the second resistor R2 is 10K, the resistance of the adjusting resistor R5 is 92K, and the feedback voltage of the chip U1 in fig. 1 is 0.8V, i.e., VREF =0.8V; when the gain shown in fig. 5 is 3, i.e., G =3, the value of the above parameter is substituted into the calculation formula of VOUT, and VOUT =10.29-3.489 × vdac can be obtained.

VOUT =10V when VDAC = 0.083V; when VDAC =2.663V, VOUT =1V. Therefore, the utility model discloses can realize the regulation of output voltage VOUT at 1V to 10V scope arbitrary value. In addition, the adjustment accuracy depends on the conversion accuracy of the digital-to-analog conversion unit 31, when the digital-to-analog conversion chip adopted by the digital-to-analog conversion unit 31 is 12 bits, the theoretical accuracy of the digital-to-analog conversion chip is 0.74mv at this time, and the adjustment accuracy of the corresponding output voltage is 2.2mv.

In summary, the utility model can adjust the output voltage of the DC-DC conversion module only by adding the adjusting resistor R5 and the adjusting voltage generating module 3 on the basis of the existing DC-DC conversion module, without changing the resistance of the feedback resistor, thus being beneficial to practical application; in addition for the PIMC chip, the utility model discloses only need let the regulation voltage continuous variation that regulation voltage produced the output of module 3 just can realize the output voltage regulation of DC-DC conversion module of higher accuracy, the output voltage control range of DC-DC conversion module is based on the voltage range who inputs regulating resistance R5 moreover, and the voltage range restriction of inputting regulating resistance R5 is little, therefore the output voltage control range of this application is big, and the application is wide.

In light of the above, the present invention is to be construed as being applicable to various changes and modifications within the scope of the present invention as defined by the appended claims. The technical scope of the present invention is not limited to the content of the specification, and must be determined according to the scope of the claims.

Claims

1. A voltage conversion circuit comprises a DC-DC conversion module and a voltage feedback module; the DC-DC conversion module comprises a voltage output end and a voltage feedback end, and the voltage feedback module comprises an input end and a feedback voltage output end; the voltage output end is electrically connected with the input end, and the feedback voltage output end is electrically connected with the voltage feedback end; the voltage regulator is characterized by further comprising a regulating resistor and a regulating voltage generating module, wherein the regulating voltage generating module comprises a regulating voltage output end, the regulating voltage output end is electrically connected with the voltage feedback end through the regulating resistor, and the regulating voltage generating module is configured to provide regulating voltage for the regulating resistor.

2. The voltage conversion circuit according to claim 1, wherein the voltage feedback module comprises a first resistor and a second resistor, one end of the first resistor is an input end of the voltage feedback module and is electrically connected to the voltage output end, the other end of the first resistor is a feedback voltage output end of the voltage feedback module and is electrically connected to the voltage feedback end and one end of the second resistor, respectively, and the other end of the second resistor is grounded.

3. The voltage conversion circuit according to claim 2, wherein the regulated voltage generating module includes a control unit, a digital-to-analog conversion unit and an amplifying unit, the control unit is electrically connected to the digital-to-analog conversion unit and configured to provide a digital signal to the digital-to-analog conversion unit, the digital-to-analog conversion unit converts the input digital signal into an analog signal, an analog signal output end of the digital-to-analog conversion unit is electrically connected to an input end of the amplifying unit, and an output end of the amplifying unit is electrically connected to the regulating resistor.

4. The voltage conversion circuit according to claim 3, wherein the regulated voltage generating module further comprises a reference voltage generating unit, and the reference voltage generating unit is electrically connected to the digital-to-analog converting unit and configured to provide a reference voltage to the digital-to-analog converting unit.

5. A voltage conversion circuit according to claim 4, characterized in that the control unit comprises a single chip microcomputer of type STM32L476RGT 6; the digital-to-analog conversion unit comprises a digital-to-analog conversion chip with the model of DAC7578 SPWR; the amplifying unit comprises an amplifying chip with the model of LM 358D; the reference voltage generating unit comprises a power supply chip with the model number of REF3030 AIDBZR.

6. The voltage conversion circuit of claim 2, wherein the regulated voltage generating module comprises a second control unit and an amplifying unit, the second control unit is electrically connected to the input terminal of the amplifying unit and configured to provide an analog voltage to the input terminal of the amplifying unit, and the output terminal of the amplifying unit is electrically connected to the regulating resistor.