CN201113814Y - Synchronous rectification circuit with voltage stabilizing function - Google Patents

Abstract

The utility model proposes a synchronous rectification circuit with a voltage stabilization function, which comprises: a transformer, which has a primary coil and a secondary coil, and the primary coil can be applied with an external voltage; a switch, which is a three-terminal element, a first end of which is coupled to a voltage output end, and a third end is coupled to one end of the secondary coil; and a control circuit, an input end of which is coupled to the voltage output end, and an output end is coupled to the second end of the switch; so that the control circuit can control the conduction degree of the switch according to the voltage output end, so that the voltage output end remains stable.

Description

Synchronous rectification circuit with voltage stabilization function

technical field

The utility model relates to a synchronous rectification circuit, especially a synchronous rectification circuit with voltage stabilizing function, the control circuit of which can control the conduction degree of the switch according to the voltage output end, so as to keep the voltage output end stable .

Background technique

Press, the synchronous rectification element in a general power supply usually only has the nature of a switch, that is, the synchronous rectification element is operated in a fully conduction region, and only has two states of on or off, so it cannot adjust or stabilize its voltage The function of the output terminal is really a fly in the ointment.

In view of this, the utility model proposes a synchronous rectification circuit with voltage stabilizing function to improve the above shortcomings.

Utility model content

An object of the present invention is to provide a synchronous rectification circuit with voltage stabilizing function, the control circuit of which can control the conduction degree of the switch according to the voltage output end, so as to keep the voltage output end stable.

In order to achieve the above-mentioned purpose, a synchronous rectification circuit with voltage stabilizing function of the present utility model is characterized in that it has:

A transformer having a primary coil to which voltage can be applied and a secondary coil;

a switch, which is a three-terminal element, the first terminal of which is coupled to a voltage output terminal, and the third terminal is coupled to one terminal of the secondary coil; and

A control circuit, its input end is coupled to the voltage output end, and its output end is coupled to the second end of the switch.

Wherein the switch is a power switch, and the power switch is an N-channel MOSFET, an N-channel junction field effect transistor, a P-channel MOSFET or a P-channel junction field effect transistor.

Wherein the first terminal is the drain of the MOSFET, the second terminal is the gate of the MOSFET, and the third terminal is the source of the MOSFET.

Wherein the control circuit is an integrated circuit or a control circuit composed of several active or passive components.

In order to achieve the above-mentioned purpose, a synchronous rectification circuit with voltage stabilizing function of the present utility model is characterized in that it has:

A transformer having a primary coil, a first secondary coil, and a second secondary coil to which an input voltage can be applied;

A first switch is a three-terminal element, the first end of which is coupled to one end of the first secondary coil, the other end of the first secondary coil is coupled to a voltage output end, and the third end is grounded ;

A second switch is a three-terminal element, the first end of which is coupled to one end of the second secondary coil, the other end of the second secondary coil is coupled to the voltage output end, and the third end is grounded ;as well as

A control circuit, whose input terminal is coupled to the voltage output terminal, and whose output terminal is coupled to the second terminals of the first switch and the second switch.

Wherein the first switch and the second switch are a power switch, and the power switch is an N-channel metal-oxide-semiconductor field-effect transistor, an N-channel junction field-effect transistor, a P-channel metal-oxide-semiconductor field-effect transistor, or a P-channel junction field effect transistor. effect transistor.

Wherein the first terminal is the drain of the MOSFET, the second terminal is the gate of the MOSFET, and the third terminal is the source of the MOSFET.

Wherein the control circuit is an integrated circuit or a control circuit composed of several active or passive components.

The beneficial effects of the utility model are:

In the synchronous rectification circuit with voltage stabilizing function of the utility model, its control circuit can control the conduction degree of the switch according to the voltage output end, so as to keep the voltage output end stable.

Description of drawings

The "synchronous rectification circuit with voltage stabilizing function" of the utility model, its features and purpose are described in detail with the accompanying drawings and examples, wherein:

FIG. 1 is a schematic diagram showing a block diagram of a synchronous rectification circuit with a voltage stabilizing function according to a preferred embodiment of the present invention.

FIG. 2 is a schematic diagram showing a block diagram of a synchronous rectification circuit with a voltage stabilizing function according to another preferred embodiment of the present invention.

FIG. 3 is a schematic diagram showing a block diagram of a synchronous rectification circuit with a voltage stabilizing function according to another preferred embodiment of the present invention.

Detailed ways

Please refer to FIG. 1 , which shows a schematic block diagram of a synchronous rectification circuit with a voltage stabilizing function according to a preferred embodiment of the present invention. As shown in the figure, the synchronous rectification circuit with voltage stabilizing function of the present invention includes: a transformer 10 ; a switch 20 ; and a control circuit 30 .

Wherein, the transformer 10 has a primary coil 11 and a secondary coil 12, and the input terminals of the primary coil 11 are respectively coupled to a positive voltage input terminal (V+) and a negative voltage input terminal (V-), which is generally Known technology, so it is not intended to repeat it here.

The switch 20 is a three-terminal element, its first end is coupled to a voltage output terminal (Vo), the third end is coupled to one end of the secondary coil 12, and its conduction degree can accept the control circuit 30 control. Wherein, the switch 20 can be a power switch, such as but not limited to N-channel metal oxide semiconductor field effect transistor, N-channel junction field effect transistor, P-channel metal oxide semiconductor field effect transistor or P-channel junction field effect transistor, Hereinafter referred to as metal oxide semiconductor field effect transistor 20, in this embodiment, an N-channel metal oxide semiconductor field effect transistor is used as an example for illustration, but it is not limited to this; wherein the first end is the metal oxide semiconductor field effect transistor The drain of the transistor 20 , the second terminal is the gate of the MOSFET 20 , and the third terminal is the source of the MOSFET 20 .

The input terminal of the control circuit 30 is coupled to the voltage output terminal (Vo), and the output terminal is coupled to the second terminal of the switch 20 . Wherein, the control circuit 30 is, for example but not limited to, an integrated circuit or a control circuit composed of several active or passive components.

For ease of operation, when the voltage output of the voltage output terminal (Vo) decreases, the control circuit 30 can make the switch 20 conduct more, so as to reduce the voltage drop on the switch 20, and at the same time make the voltage output of the voltage output terminal pick up; when the voltage output of the voltage output terminal is too high, the control circuit 30 can make the switch 20 turn on less, to increase the voltage drop on the switch, and at the same time reduce the voltage output of the voltage output terminal, so that the voltage output end remains stable. In this way, by the synchronous rectification circuit with voltage stabilizing function of the present utility model, the switch 20 can maintain the stability of the voltage output end in addition to the function of synchronous rectification, therefore, the synchronous rectification element in the known power supply can indeed be improved. shortcoming.

Please refer to FIG. 2 , which shows a schematic block diagram of a synchronous rectification circuit with a voltage stabilizing function according to another preferred embodiment of the present application. As shown in the figure, in the synchronous rectification circuit with voltage stabilizing function of the present invention, the switch 20 can be placed under the secondary coil 12 to achieve the function as shown in FIG. 1 .

Please refer to FIG. 3 , which shows a schematic block diagram of a synchronous rectification circuit with a voltage stabilizing function according to another preferred embodiment of the present application. As shown in the figure, the synchronous rectification circuit with voltage stabilizing function of the present invention includes: a transformer 40 ; a first switch 50 ; a second switch 60 ; and a control circuit 70 .

Wherein, the transformer 40 has a primary coil 41, a first secondary coil 42 and a second secondary coil 43, and the input terminals of the primary coil 41 are respectively coupled to a positive voltage input terminal (V+) and a negative voltage input terminal (V+). The voltage input terminal (V-) is a generally known technology, so it is not intended to repeat it here.

The first switch 50 is a three-terminal element, the first end of which is coupled to one end of the first secondary coil 42, and the other end of the first secondary coil 42 is coupled to a voltage output terminal (Vo). , the third end is grounded, and its conduction degree can be controlled by the control circuit 70 . Wherein, the first switch 50 can be a power switch, such as but not limited to N-channel MOSFET, N-channel junction field effect transistor, P-channel MOSFET or P-channel junction field effect transistor. Transistors, hereinafter referred to as the first metal-oxide-semiconductor field-effect transistor 50, in this embodiment, an N-channel metal-oxide-semiconductor field-effect transistor is used as an example for illustration, but it is not limited thereto; wherein the first terminal is the The drain (drain) of the first metal oxide semiconductor field effect transistor 50, the second terminal is the gate (gate) of the first metal oxide semiconductor field effect transistor 50, and the third terminal is the first metal oxide semiconductor field effect transistor. The source of the effect transistor 50 .

The second switch 60 is also a three-terminal element, its first end is coupled to one end of the second secondary coil 43, and the other end of the second secondary coil 43 is coupled to the voltage output terminal (Vo) , the third terminal is grounded, and its conduction degree can also be controlled by the control circuit 70 . Wherein, the second switch 60 can be a power switch, such as but not limited to N-channel MOSFET, N-channel junction field effect transistor, P-channel MOSFET or P-channel junction field effect transistor. Transistors, hereinafter referred to as the second metal-oxide-semiconductor field-effect transistor 60, in this embodiment, an N-channel metal-oxide-semiconductor field-effect transistor is used as an example for illustration, but it is not limited thereto; wherein the first terminal is the The drain (drain) of the second metal oxide semiconductor field effect transistor 60, the second end is the gate (gate) of the second metal oxide semiconductor field effect transistor 60, the third end is the second metal oxide semiconductor field effect transistor The source of the effect transistor 60 (source).

The input terminal of the control circuit 70 is coupled to the voltage output terminal (Vo), and the output terminal is coupled to the second terminals of the first switch 50 and the second switch 60 . Wherein, the control circuit 70 is, for example but not limited to, an integrated circuit or a control circuit composed of several active or passive components.

For ease of operation, when the voltage output of the voltage output terminal (Vo) decreases, the control circuit 70 can make the first switch 50 and the second switch 60 conduct more, so as to reduce the voltage of the first switch 50 and the second switch 60. The voltage drop on the switch 60 makes the voltage output of the voltage output terminal pick up at the same time; when the voltage output of the voltage output terminal is too high, the control circuit 70 can make the first switch 50 and the second switch 60 conduction less, to increase The voltage drop on the first switch 50 and the second switch 60 simultaneously reduces the voltage output at the voltage output end, so that the voltage output end remains stable. In this way, by the synchronous rectification circuit with voltage stabilizing function of the present utility model, the first switch 50 and the second switch 60 can maintain the stability of the voltage output terminal in addition to the function of synchronous rectification, so the known power supply can indeed be improved. Disadvantages of synchronous rectification components in the supply.

Therefore, through the implementation of the synchronous rectification circuit with voltage stabilizing function of the present invention, in addition to the function of synchronous rectification, the control circuit can also control the conduction degree of the switch according to the voltage output terminal, so that the The voltage output end maintains the advantages of being stable, therefore, the shortcomings of the synchronous rectification element in the known power supply can indeed be improved.

What is disclosed in this case is a preferred embodiment, and any partial change or modification derived from the technical idea of this case and easily deduced by a person familiar with the technology does not depart from the scope of the patent right of this case.

Claims (8)

1. the circuit of synchronous rectification of a tool voltage stabilizing function is characterized in that, it has:

One transformer, but it has primary coil and a level coil of an applied voltage;

One switch is a three-terminal element, and its first end is coupled to a voltage output end, and the 3rd end is coupled to an end of this secondary coil; And

One control circuit, its input is coupled to this voltage output end, and output then is coupled to second end of this switch.

2. the circuit of synchronous rectification of tool voltage stabilizing function as claimed in claim 1, it is characterized in that, wherein this switch is a power switch, and this power switch is that n channel metal oxide semiconductor field-effect transistor, N passage connect surface field-effect transistor, p channel metal oxide semiconductor field-effect transistor or P passage and connect surface field-effect transistor.

3. the circuit of synchronous rectification of tool voltage stabilizing function as claimed in claim 2, it is characterized in that, wherein this first end is that this metal oxide semiconductor field effect is answered transistor drain, this second end is that this metal oxide semiconductor field effect is answered transistorized grid, and the 3rd end is that this metal oxide semiconductor field effect should transistorized source electrode.

4. the circuit of synchronous rectification of tool voltage stabilizing function as claimed in claim 1 is characterized in that, wherein this control circuit is an integrated circuit or the control circuit be made up of some actives or passive device.

5. the circuit of synchronous rectification of a tool voltage stabilizing function is characterized in that, it has:

One transformer, but it has primary coil and one first secondary coil and a second subprime coil of an input applied voltage;

One first switch is a three-terminal element, and its first end is coupled to an end of this first secondary coil, and the other end of this first secondary coil then is coupled to a voltage output end, and the 3rd end is ground connection then;

One second switch is a three-terminal element, and its first end is coupled to an end of this second subprime coil, and the other end of this second subprime coil then is coupled to this voltage output end, and the 3rd end is ground connection then; And

One control circuit, its input is coupled to this voltage output end, and output then is coupled to second end of this first switch and second switch.

6. the circuit of synchronous rectification of tool voltage stabilizing function as claimed in claim 5, it is characterized in that, wherein this first switch and second switch are a power switch, and this power switch is that n channel metal oxide semiconductor field-effect transistor, N passage connect surface field-effect transistor, p channel metal oxide semiconductor field-effect transistor or P passage and connect surface field-effect transistor.

7. the circuit of synchronous rectification of tool voltage stabilizing function as claimed in claim 6, it is characterized in that, wherein this first end is that this metal oxide semiconductor field effect is answered transistor drain, this second end is that this metal oxide semiconductor field effect is answered transistorized grid, and the 3rd end is that this metal oxide semiconductor field effect should transistorized source electrode.

8. the circuit of synchronous rectification of tool voltage stabilizing function as claimed in claim 7 is characterized in that, wherein this control circuit is an integrated circuit or the control circuit be made up of some actives or passive device.

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