CN210669563U

CN210669563U - Direct-current voltage conversion circuit

Info

Publication number: CN210669563U
Application number: CN201921621952.XU
Authority: CN
Inventors: 李明通; 李干富
Original assignee: Cheng Li Xin Electronic Technology Co ltd
Current assignee: Cheng Li Xin Electronic Technology Co ltd
Priority date: 2019-09-26
Filing date: 2019-09-26
Publication date: 2020-06-02
Anticipated expiration: 2029-09-26

Abstract

The utility model discloses a direct current voltage converting circuit, including reference voltage circuit, control circuit, feedback circuit and tank circuit. The reference voltage circuit converts input voltage into reference voltage and outputs the reference voltage to the reference end of the control circuit, the feedback circuit is connected in parallel to the two ends of the energy storage circuit, and the feedback circuit measures voltage change of the energy storage circuit and outputs the feedback voltage to the feedback end of the control circuit. The control circuit controls the opening and the closing of the charging path of the energy storage circuit according to the comparison of the feedback voltage and the reference voltage value, the energy storage circuit is charged in a time-sharing mode, and the energy storage circuit outputs electric energy to a load at the same time. Through the circulation of above-mentioned process, the utility model discloses a direct current voltage conversion circuit can provide stable voltage according to the load demand to this kind of timesharing can reduce conversion circuit's electric energy loss for the mode of energy storage circuit power transmission, improves conversion efficiency, can satisfy the application sight that has the harsh requirement to stand-by power consumption.

Description

Direct-current voltage conversion circuit

Technical Field

The utility model relates to a power technical field, in particular to direct current voltage conversion circuit.

Background

The MCU of small household appliances in daily life needs to supply 5V or 12V voltage, and the prior art generally depends on a linear voltage regulator of LM78 series to convert the high voltage of a driving circuit into the voltage needed by the MCU.

Taking a common LM7805 as an example, the highest input voltage that LM7805 can withstand is 35V, and the maximum output current is 1.5A. When the difference between the input voltage and the output voltage is large, most of the energy is released as heat, the conversion efficiency is low, and a radiator with a large enough size needs to be equipped to ensure the normal operation of the circuit. Such a voltage conversion circuit based on a linear voltage regulator cannot cope with application scenarios with strict requirements on standby power consumption.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to solve one of the technical problem that exists among the prior art at least, provide a direct current voltage conversion circuit, can effectively reduce energy loss, reduce calorific capacity.

The utility model provides a direct current voltage converting circuit, include:

reference voltage circuit, control circuit, feedback circuit and tank circuit, reference voltage circuit's input links to each other with external power source, reference voltage circuit's output is connected control circuit's reference end, control circuit's feedback end is connected feedback circuit's output, feedback circuit's input is connected tank circuit's input, tank circuit's input is connected control circuit's output, tank circuit's output is connected the load.

According to the utility model discloses a direct voltage conversion circuit, control circuit controls the timesharing of switching on the tank circuit according to the load voltage value of feedback circuit and the magnitude relation of the reference voltage value of reference voltage circuit output, cuts off the charging to the tank circuit when load voltage value is higher than or equal to the reference voltage value; when the load consumes the electric energy in the energy storage circuit, the feedback voltage value is reduced to be lower than the reference voltage value, and the control circuit is opened to charge the energy storage circuit. By the mode, electric energy can be stably transmitted to the load according to the requirement of the load, the energy loss of the voltage conversion circuit is reduced, and the conversion efficiency is improved.

Further, the control circuit includes:

PMOS pipe Q1, NMOS pipe Q2 and first operational amplifier IC1A, the drain electrode of PMOS pipe Q1 is connected external power supply, PMOS pipe Q1's source is connected the input of energy-storing circuit, PMOS pipe Q1's grid passes through first resistance R1 and connects the drain electrode of NMOS pipe Q2, NMOS pipe Q2's source ground connection, NMOS pipe Q2's grid passes through second resistance R2 and connects internal power source VCC, the reverse input of first operational amplifier IC1A connects the output of feedback circuit, the syntropy input of first operational amplifier IC1A is connected the output of reference voltage circuit, the output of first operational amplifier IC1A is connected the grid of NMOS pipe Q2.

The first operational amplifier IC1A functions as a voltage comparator, wherein the inverting input terminal thereof serves as a reference terminal, the inverting input terminal thereof serves as a comparison terminal, and the output terminal thereof outputs a high level or a low level to the gate of the NMOS transistor Q2 according to the comparison result, thereby controlling the conduction and the cut-off of the PMOS transistor Q1 and the NMOS transistor Q2, and further controlling the time-sharing conduction and the cut-off of the charging of the energy storage circuit. Because the MOS tube has small on-resistance, the heat productivity is small, an external radiator is not needed, and the conversion efficiency of the conversion circuit is further improved.

In a further improvement of the above solution, the control circuit further includes:

the voltage-stabilizing diode comprises a voltage-stabilizing tube ZD1 and a third resistor R3, wherein the anode of the voltage-stabilizing tube ZD1 is connected with the drain electrode of the PMOS tube Q1, the cathode of the voltage-stabilizing tube ZD1 is connected with the grid electrode of the PMOS tube Q1, and the third resistor R3 is connected at two ends of the voltage-stabilizing tube ZD1 in parallel.

The voltage regulator tube ZD1 can clamp the grid voltage of the PMOS tube Q1, the resistor R3 is used for releasing grid charges, the resistance value grid charges are accumulated, the PMOS tube is prevented from being broken down by overvoltage, the stability of the direct current voltage conversion circuit is enhanced, and the service life of the direct current voltage conversion circuit is prolonged.

Further, the reference voltage circuit includes:

and an inverting input terminal of the second operational amplifier IC1B of the second operational amplifier IC1B is connected to an output terminal of the second operational amplifier IC1B, and a non-inverting input terminal of the second operational amplifier IC1B is connected to the external power supply through a fourth resistor R4.

Here, the second operational amplifier IC1B functions as a voltage follower, and has the functions of a buffer and an isolator, so that the input resistance of the circuit can be increased, the input capacitance can be reduced, and the noise of the input voltage can be isolated.

Further, the reference voltage circuit further includes:

and the anode and the gate of the thyristor Q3 are connected with the same-direction input end of the second operational amplifier IC1B, and the cathode of the thyristor Q3 is grounded.

The thyristor has the function of clamping voltage, and the thyristor Q3 is used for overvoltage protection to protect the operational amplifier from being broken down, so that the stability and the performance of the circuit are further improved.

Further, the reference voltage circuit further includes:

and a first capacitor C1, one end of the first capacitor C1 being connected to the external power supply, and the other end of the first capacitor C1 being grounded.

The first capacitor C1 acts as a filter to further reduce input voltage noise interference.

Further, the feedback circuit includes:

the feedback circuit comprises a fifth resistor R5 and a sixth resistor R6 which are connected in series, wherein one end, back to the sixth resistor R6, of the fifth resistor R5 is connected with the input end of the energy storage circuit, one end, back to the fifth resistor R5, of the sixth resistor R6 is grounded, and a series connection node of the fifth resistor R5 and the sixth resistor R6 is connected with the feedback end of the control circuit.

Preferably, the sixth resistor R6 is a piezo-resistor. The voltage dependent resistor can clamp voltage during overvoltage to protect the device from being damaged by overvoltage.

Further, the tank circuit includes:

the circuit comprises a second capacitor C2, a third capacitor C3 and an inductor L1, wherein one end of the second capacitor C2 is connected with the output end of the control circuit, the other end of the second capacitor C2 is grounded, one end of the third capacitor C3 is connected with a load, the other end of the third capacitor C3 is grounded, one end of the inductor L1 is connected with the output end of the control circuit, and the other end of the inductor L1 is connected with the load.

The inductor L1 can filter high frequency interference, further improve the quality of the power supply of the DC voltage conversion circuit to the load.

Drawings

The present invention will be further described with reference to the accompanying drawings and examples;

fig. 1 is a circuit block diagram of an embodiment of the present invention;

fig. 2 is a schematic circuit diagram according to an embodiment of the present invention.

Detailed Description

This section will describe in detail the embodiments of the present invention, preferred embodiments of the present invention are shown in the attached drawings, which are used to supplement the description of the text part of the specification with figures, so that one can intuitively and vividly understand each technical feature and the whole technical solution of the present invention, but they cannot be understood as the limitation of the protection scope of the present invention.

In the description of the present invention, it should be understood that the orientation or positional relationship indicated with respect to the orientation description, such as up, down, front, rear, left, right, etc., is based on the orientation or positional relationship shown in the drawings, and is only for convenience of description and simplification of description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present invention.

In the description of the present invention, a plurality of means are one or more, a plurality of means are two or more, and the terms greater than, less than, exceeding, etc. are understood as not including the number, and the terms greater than, less than, within, etc. are understood as including the number. If the first and second are described for the purpose of distinguishing technical features, they are not to be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated or implicitly indicating the precedence of the technical features indicated.

In the description of the present invention, unless there is an explicit limitation, the words such as setting, installation, connection, etc. should be understood in a broad sense, and those skilled in the art can reasonably determine the specific meanings of the above words in combination with the specific contents of the technical solution.

Referring to fig. 1, the dc voltage conversion circuit includes a reference voltage circuit 1, a control circuit 2, a feedback circuit 3, and a tank circuit 4. The reference voltage circuit 1 outputs reference voltage to the control circuit 2 according to the input voltage, the control circuit 2 transmits electric energy to the energy storage circuit 4, the energy storage circuit 4 transmits the electric energy stored in the energy storage circuit to a load, and the feedback circuit 3 measures the voltage of the energy storage circuit 4 and feeds the voltage back to the control circuit 2. The control circuit 2 compares the feedback voltage with a reference voltage value and controls the on and off of the electric energy transmission to the energy storage circuit 4. When the feedback voltage is lower than the reference voltage, the control circuit 2 outputs voltage to the energy storage circuit 4 to charge the energy storage circuit 4, the feedback voltage measured by the feedback circuit 3 is increased along with the charging of the energy storage circuit 4, and when the feedback voltage is no longer lower than the reference voltage, the control circuit 2 turns off the electric energy transmission to the energy storage circuit 4. When the load consumes the electric energy stored in the tank circuit 4, the feedback voltage drops, and when the feedback voltage is lower than the reference voltage, the control circuit 2 turns on the electric energy delivery to the tank circuit 4 again. Through the cyclic reciprocating of the process, the direct-current voltage conversion circuit can stably convert the input voltage into the voltage required by the load according to the use requirement of the load. And the time-sharing power transmission mode can reduce the power loss during the standby of the load and improve the conversion efficiency of the conversion circuit.

Referring to fig. 2, a specific circuit schematic diagram of an embodiment of the present invention is shown.

In the present embodiment, the control circuit 2 is composed of a PMOS transistor Q1, an NMOS transistor Q2, a voltage regulator ZD1, a resistor R1, a resistor R2, a resistor R3, and an operational amplifier IC 1A. The drain of the PMOS transistor Q1 is connected to the input voltage, the source thereof is connected to the input terminal of the tank circuit 4, and the gate thereof is connected to the drain of the NMOS transistor Q2 through the resistor R1. The voltage regulator tube ZD1 and the resistor R3 are connected in parallel at two ends of the drain and the grid of the PMOS tube Q1, and protect the PMOS tube Q1 from breakdown. The gate of the NMOS transistor Q2 is connected to the internal power source VCC through a resistor R2, and the source thereof is grounded. The output end of the operational amplifier IC1A is connected with the grid of the NMOS tube Q2, the same-direction input end of the operational amplifier IC1A is connected with the output end of the reference voltage circuit 1, and the reverse-direction input end thereof is connected with the output end of the feedback circuit 3.

In the present embodiment, the reference voltage circuit 1 is composed of an operational amplifier IC1B, a resistor R4, a thyristor Q3, and a capacitor C1. The output of the operational amplifier IC1B is connected as the output of the reference voltage circuit 1 to the unidirectional input of the operational amplifier IC1A, which is connected on the one hand to the gate of the thyristor Q3 and on the other hand to the input voltage via the resistor R4, the inverting input of which is connected to the output. The anode of the thyristor Q3 is connected with the equidirectional input end of the operational amplifier IC1B, and the cathode is grounded and used as overvoltage protection of the operational amplifier IC 1B. The capacitor C1 has one end connected to the input voltage and the other end connected to ground. Preferably, in the present embodiment, the IC1 composed of the operational amplifier IC1A and the operational amplifier IC1B is a single-source dual operational amplifier circuit LM 358.

In the present embodiment, the feedback circuit 3 is composed of a resistor R5 and a resistor R6. The resistor R5 and the resistor R6 are connected in series and are connected in parallel at two ends of the energy storage circuit 4. The end of R5 not connected with R6 is connected with the source of PMOS transistor Q1, and the end of R6 not connected with R5 is grounded. The voltage across the R6 is fed back to the control circuit 2 as a feedback voltage, and one end of the R6 connected to the R5 is connected to the non-inverting input terminal of the operational amplifier IC 1A. Preferably, in this embodiment, the resistor R6 is a voltage dependent resistor, and can protect the operational amplifier IC1A from being damaged by overvoltage.

In the present embodiment, the tank circuit 4 is composed of a capacitor C2, a capacitor C3, and an inductor L1. One end of the capacitor C2 is connected to the source of the POMS tube Q1, and the other end is grounded. One end of the inductor L1 is connected to the source of the PMOS transistor Q1, and the other end is connected to the load. One end of the capacitor C3 is connected to the load, and the other end is grounded.

The input voltage is controlled by the control circuit 2 to be conducted in a time-sharing way, and the electric energy is transmitted to the energy storage circuit 4, namely the capacitor C2 and the capacitor C3. The operational amplifier IC1A is used as a voltage comparator, when the feedback voltage measured by the feedback circuit 3 is lower than the reference voltage provided by the reference voltage circuit 1, the operational amplifier IC1A outputs a low level to the NMOS transistor Q2, so that the NMOS transistor Q2 is turned off, the PMOS transistor Q1 is also turned off, and the input voltage cannot transmit the electric energy to the capacitor C2 and the capacitor C3 through the PMOS transistor Q1. When the load consumes part of the electric energy stored in the capacitor C2 and the capacitor C3 during the operation, due to the characteristics of the capacitors, the voltage of the capacitors does not suddenly change at the moment of discharging, but the discharging current of the capacitors suddenly changes, the feedback voltage measured by the feedback circuit 3 changes, and after the feedback voltage is lower than the reference voltage, the operational amplifier IC1A rapidly outputs a high level to the grid electrode of the NMOS tube Q2, the NMOS tube Q2 is conducted, further the PMOS tube Q1 is conducted, the input voltage is transmitted to the capacitor C2 and the capacitor C3 through the PMOS tube Q1 to be charged, and the electric energy in the energy storage circuit 4 is recovered to a required value. The above actions are repeated circularly, and stable voltage can be transmitted to the load as required through filtering of the inductor L1, so that the consumption of electric energy is reduced, the voltage conversion efficiency is improved, and the service life is prolonged. Meanwhile, due to the low on-resistance of the MOS tube, the heat productivity of the circuit can be reduced, a fan heater does not need to be arranged on the circuit, the size of the circuit is reduced, the cost is reduced, and meanwhile, the conversion efficiency of the circuit is further improved.

Meanwhile, the operational amplifier IC1B in the reference voltage circuit 1 is used as a voltage follower, has the functions of an isolator and a buffer, can cope with sudden changes of input voltage, and further improves the stability of the circuit. The capacitor C1 may also filter the input voltage to remove noise. The voltage clamping function of the thyristor Q3, the voltage regulator tube ZD1 and the voltage dependent resistor R2 can effectively prevent the destructive influence of the sudden change of the input voltage and the load terminal voltage on main devices.

It is understood that the functions of the operational amplifier IC1A and the operational amplifier IC1B may be replaced by a multi-stage circuit composed of transistors with the same functions, and the PMOS transistor Q1 and the NMOS transistor Q2 may be replaced by other transistors such as a triode or a thyristor.

According to the utility model discloses a direct current voltage conversion circuit carries out the timesharing through control circuit for energy storage circuit and charges, and energy storage circuit provides the electric energy for the load according to the load is required again, has effectively reduced the electric energy loss among the voltage conversion process, improves electric energy conversion efficiency to reduce circuit calorific capacity.

The embodiments of the present invention have been described in detail with reference to the accompanying drawings, but the present invention is not limited to the above embodiments, and various changes can be made without departing from the spirit of the present invention within the knowledge of those skilled in the art.

Claims

1. A dc voltage conversion circuit, comprising:

2. The dc voltage conversion circuit of claim 1, wherein the control circuit comprises:

3. The dc voltage conversion circuit of claim 2, wherein the control circuit further comprises:

4. The dc voltage conversion circuit according to claim 1, wherein the reference voltage circuit comprises:

5. The dc voltage conversion circuit of claim 4, wherein the reference voltage circuit further comprises:

6. The dc voltage conversion circuit of claim 4, wherein the reference voltage circuit further comprises:

7. The dc voltage conversion circuit of claim 1, wherein the feedback circuit comprises:

8. The dc voltage converting circuit of claim 7, wherein said sixth resistor R6 is a voltage dependent resistor.

9. The dc voltage conversion circuit of claim 1, wherein the tank circuit comprises: