CN214900645U

CN214900645U - MOS pipe control circuit of low-voltage conversion rate

Info

Publication number: CN214900645U
Application number: CN202121235489.2U
Authority: CN
Inventors: 许峰
Original assignee: Qingdao Yuantong Electronic Co ltd
Current assignee: Qingdao Yuantong Electronic Co ltd
Priority date: 2021-06-03
Filing date: 2021-06-03
Publication date: 2021-11-26
Anticipated expiration: 2031-06-03

Abstract

The utility model discloses a MOS pipe control circuit of low voltage conversion rate, including pulse width modulation chip, operational amplifier, second resistance, third resistance, first electric capacity to third electric capacity, MOS pipe, transformer, the pulse width modulation chip is connected with the anodal and negative pole of power respectively, the positive phase input end of transformer is connected with the power supply anodal, the inverting input termination MOS pipe's of transformer D utmost point, the G utmost point of MOS pipe connects the one end of operational amplifier's output, first electric capacity. The utility model discloses its circuit structure is simple, and is safe, stable, low in manufacturing cost, and the commonality is also very good, uses sine wave signal to be used for driving the MOS pipe for the MOS pipe is switching on and turn-off voltage change rate in the twinkling of an eye and is reducing by a wide margin, avoids the MOS pipe to open and turn-off in the twinkling of an eye, produces higher dV/dt, influences the electromagnetic compatibility characteristic and the noise characteristic of product.

Description

MOS pipe control circuit of low-voltage conversion rate

Technical Field

The utility model relates to a MOS manages technical field, specifically is a MOS pipe control circuit of low voltage conversion rate.

Background

In the application of the switching power supply, the power MOS tube is used as a core device of the switch and is controlled by a driving signal of a control chip to realize periodic switching and chop input voltage. In the field of present switching power supplies, the operating frequency is increasingly improved, the voltage conversion rate between the drain electrode and the source electrode of the MOS transistor is increasingly faster, and a higher voltage change rate is generated, so that the electromagnetic compatibility and the output noise characteristic of the switching power supply are poorer.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to provide a MOS pipe control circuit of low voltage conversion rate, its circuit structure is simple, and is safe, stable, low in manufacturing cost, the commonality is also very good, uses sine wave signal to be used for driving the MOS pipe for the MOS pipe is opening and is turn-offed the voltage variation rate in the twinkling of an eye and reduce by a wide margin, avoids the MOS pipe opening and turn-offe in the twinkling of an eye, produces higher dV/dt, influences the electromagnetic compatibility characteristic and the noise characteristic of product.

In order to achieve the above object, the utility model provides a following technical scheme: the MOS tube control circuit with the low voltage conversion rate comprises a pulse width modulation chip, an operational amplifier, a second resistor, a third resistor, a first capacitor to a third capacitor, an MOS tube and a transformer, wherein the pulse width modulation chip is respectively connected with the anode and the cathode of a power supply, the positive phase input end of the transformer is connected with the anode of the power supply, the negative phase input end of the transformer is connected with the D electrode of the MOS tube, the G electrode of the MOS tube is connected with the output end of the operational amplifier and one end of the first capacitor, the positive phase input end of the operational amplifier is connected with one end of the third resistor, the negative phase input end of the operational amplifier is connected with the other end of the first capacitor and one end of the second resistor, the other end of the second resistor is connected with the control input end of the pulse width modulation chip, the power end of the operational amplifier is connected with the anode of the power supply, one end of the second capacitor and one end of the third capacitor, the second capacitor, The third capacitor, the third resistor and the S pole of the MOS tube are all grounded.

Preferably, the pulse width modulation chip is an ISL8841A chip.

Preferably, the pulse width modulation circuit further comprises a first resistor and a fourth capacitor, wherein one end of the first resistor is connected with a VREF pin of the pulse width modulation chip, one end of the fourth capacitor is connected with the other end of the first resistor and an RTCT pin of the pulse width modulation chip, and the other end of the fourth capacitor is connected with a negative electrode of the power supply.

Preferably, the pulse width modulation circuit further comprises a fifth capacitor, the fifth capacitor is connected with a COMP pin of the pulse width modulation chip, and the other end of the fifth capacitor is connected with a negative electrode of the power supply.

Preferably, the second capacitor, the third capacitor, the fourth capacitor and the fifth capacitor are decoupling capacitors.

Preferably, the operational amplifier, the first capacitor, the second resistor and the third resistor together form an integrator.

Preferably, the pulse width modulation chip outputs a rectangular wave signal.

Preferably, the operational amplifier outputs a sine wave signal.

Preferably, the first resistor and the first capacitor are detachable plug-in structures.

Compared with the prior art, the beneficial effects of the utility model are that:

1. the utility model discloses jointly use pulse width modulation chip and integrator, carry out the integral to the rectangular wave that the pulse width modulation chip produced through the integrator, finally export fixed frequency, the sine wave signal that the precision is high, then export for the MOS pipe, be used for driving the MOS pipe, make the MOS pipe reduce by a wide margin at the voltage rate of change in the moment of switching on and turn-off, avoid the MOS pipe in the moment of opening and turn-off, produce higher dV/dt, influence the electromagnetic compatibility characteristic and the noise characteristic of product.

2. The utility model discloses a first resistance, first electric capacity are removable grafting structure, detachable grafting structure promptly, are convenient for change the first electric capacity of the first resistance R1 of different resistances or different resistances to change the frequency of pulse width modulation chip output rectangular waveform.

3. The utility model discloses a second electric capacity, third electric capacity, fifth electric capacity, sixth electric capacity are decoupling capacitance for the filtering noise.

4. The utility model discloses a circuit structure is simple, and is safe, stable, and low in manufacturing cost can use widely on a large scale to the range of application is wide, and the commonality is also very good.

Additional aspects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.

Drawings

Fig. 1 is a schematic circuit diagram of the present invention.

In the figure: c1, a first capacitance; c2, a second capacitor; c3, a third capacitance; c4, a fourth capacitance; c5, a fifth capacitance; r1, a first resistor; r2, a second resistor; r3, third resistor; u1, pulse width modulation chip; u2, operational amplifier; q1 and MOS tube; t1, transformer;

Detailed Description

The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative work belong to the protection scope of the present invention.

In the present invention, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "fixed" are to be construed broadly and may, for example, be fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the present invention can be understood according to specific situations by those skilled in the art.

Referring to fig. 1, the present invention provides a technical solution: a MOS tube control circuit with low voltage conversion rate comprises a pulse width modulation chip U1, an operational amplifier U2, a second resistor R2, a third resistor R3, a first capacitor C1 to a third capacitor C3, a MOS tube Q1 and a transformer T1, wherein the pulse width modulation chip U1 is respectively connected with the positive pole and the negative pole of a power supply, the positive phase input end of the transformer T1 is connected with the positive pole of the power supply, the reverse phase input end of the transformer T1 is connected with the D pole of the MOS tube Q1, the G pole of the MOS tube Q1 is connected with the output end of an operational amplifier U2 and one end of a first capacitor C1, the positive phase input end of the operational amplifier U2 is connected with one end of the third resistor 686R 3, the reverse phase input end of the operational amplifier U2 is connected with the other end of a first capacitor C1 and one end of a second resistor R2, the other end of a second resistor R2 is connected with the pulse width control input end of the modulation chip U1, the positive pole of the operational amplifier U2 is connected with the positive pole of the power supply, one end of a second capacitor C2 and one end of a third capacitor C3, the S poles of the second capacitor C2, the third capacitor C3, the third resistor R3 and the MOS transistor Q1 are all grounded, the pulse width modulation chip U1 outputs a rectangular wave signal, and the operational amplifier U2 outputs a sine wave signal.

The pulse width modulation chip U1 selects an ISL8841A chip, and the frequency of the rectangular wave output by the pulse width modulation chip U1 can be set by presetting the values of a fixed frequency resistor and a capacitor around the pulse width modulation chip U1.

The utility model discloses still include first resistance R1, fourth electric capacity C4, fifth electric capacity C5, a termination pulse width modulation chip U1's VREF foot of first resistance R1, a termination first resistance R1's the other end of fourth electric capacity C4, pulse width modulation chip U1's RTCT foot, a termination power negative pole of fourth electric capacity C4. The fifth capacitor C5 is connected with the COMP pin of the pulse width modulation chip U1, and the other end of the fifth capacitor C5 is connected with the negative electrode of the power supply.

The first resistor R1 and the first capacitor C1 are used for setting the frequency of the rectangular waveform output by the pulse width modulation chip U1.

The second capacitor C2, the third capacitor C3, the fourth capacitor C4 and the fifth capacitor C5 are decoupling capacitors for filtering noise.

The operational amplifier U2, the first capacitor C1, the second resistor R2 and the third resistor R3 jointly form an integrator, and the integrator performs integration operation on the rectangular wave generated by the pulse width modulation chip U1 and outputs a required sinusoidal signal.

The MOS transistor Q1 chops the input voltage, and the T1 transformer is used for power transmission of the switching power supply.

The first resistor R1 and the first capacitor C1 are detachable plug structures, namely detachable plug structures, so that the first resistor R1 with different resistance values or the first capacitor C1 with different resistance values can be replaced conveniently, and the frequency of the rectangular waveform output by the pulse width modulation chip U1 is changed.

The working principle is as follows: the power supply supplies power to a pulse width modulation chip U1 and an operational amplifier U2, the pulse width modulation chip U1 outputs a rectangular waveform according to the frequency set by a first resistor R1 and a first capacitor C1, and after an integrator is formed by the operational amplifier U2, the first capacitor C1, a second resistor R2 and a third resistor R3, the rectangular waveform generated by the pulse width modulation chip U1 is integrated by the integrator, a sine wave signal with fixed frequency and high precision is finally output, and then the sine wave signal is output to an MOS tube Q1 to drive the MOS tube Q1, so that the voltage change rate of the MOS tube Q1 at the moment of switching on and off is greatly reduced, and the phenomenon that the MOS tube generates higher dV/dt at the moment of switching on and off is avoided, and the electromagnetic compatibility characteristic and the noise characteristic of a product are influenced is avoided.

In the description of the present invention, it should be understood that the indicated orientation or positional relationship 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 indicated device or element must have a particular orientation, be constructed and operated in a particular orientation, and thus should not be construed as limiting the present invention.

In the description herein, references to the description of the term "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.

Claims

1. The utility model provides a MOS pipe control circuit of low voltage conversion rate which characterized in that: comprises a pulse width modulation chip, an operational amplifier, a second resistor, a third resistor, a first capacitor to a third capacitor, an MOS tube and a transformer, the pulse width modulation chip is respectively connected with the anode and the cathode of a power supply, the positive phase input end of the transformer is connected with the anode of the power supply, the inverting input end of the transformer is connected with the D pole of the MOS tube, the G pole of the MOS tube is connected with the output end of the operational amplifier and one end of the first capacitor, the non-inverting input end of the operational amplifier is connected with one end of the third resistor, the inverting input end of the operational amplifier is connected with the other end of the first capacitor and one end of the second resistor, the other end of the second resistor is connected with the control input end of the pulse width modulation chip, the power supply end of the operational amplifier is connected with the anode of the power supply, one end of the second capacitor and one end of the third capacitor, and the second capacitor, the third resistor and the S electrode of the MOS tube are all grounded.

2. The low voltage conversion rate MOS transistor control circuit of claim 1, wherein: the pulse width modulation chip is an ISL8841A chip.

3. The low voltage conversion rate MOS transistor control circuit of claim 2, wherein: the pulse width modulation circuit further comprises a first resistor and a fourth capacitor, one end of the first resistor is connected with a VREF pin of the pulse width modulation chip, one end of the fourth capacitor is connected with the other end of the first resistor and an RTCT pin of the pulse width modulation chip, and the other end of the fourth capacitor is connected with a negative electrode of a power supply.

4. The MOS tube control circuit with low voltage conversion rate of claim 3, wherein: the pulse width modulation circuit further comprises a fifth capacitor, wherein the fifth capacitor is connected with a COMP pin of the pulse width modulation chip, and the other end of the fifth capacitor is connected with a negative electrode of a power supply.

5. The MOS tube control circuit with low voltage conversion rate of claim 4, wherein: the second capacitor, the third capacitor, the fourth capacitor and the fifth capacitor are decoupling capacitors.

6. The low voltage conversion rate MOS transistor control circuit of claim 1, wherein: the operational amplifier, the first capacitor, the second resistor and the third resistor jointly form an integrator.

7. The low voltage conversion rate MOS transistor control circuit of claim 1, wherein: the pulse width modulation chip outputs a rectangular wave signal.

8. The low voltage conversion rate MOS transistor control circuit of claim 1, wherein: the operational amplifier outputs a sine wave signal.

9. The MOS tube control circuit with low voltage conversion rate of claim 3, wherein: the first resistor and the first capacitor are of detachable plug-in structures.