CN209930151U

CN209930151U - Power supply circuit of temperature control liquid crystal screen controller

Info

Publication number: CN209930151U
Application number: CN201921030719.4U
Authority: CN
Inventors: 申玉柳
Original assignee: JIAXING FUQIDUO THERMOSTAT BED CO Ltd
Current assignee: JIAXING FUQIDUO THERMOSTAT BED CO Ltd
Priority date: 2019-07-03
Filing date: 2019-07-03
Publication date: 2020-01-10
Anticipated expiration: 2029-07-03

Abstract

A power supply circuit of a temperature control liquid crystal screen controller comprises an electronic switch circuit connected with a live wire, a rectifier bridge connected with the electronic switch circuit and a zero line, a filter capacitor connected with the rectifier bridge, a starting trigger circuit connected with the rectifier bridge, a half-bridge converter connected with a first output end, a second output end and the starting trigger circuit of the rectifier bridge, and a magnetic core isolation step-down transformer connected with the first output end and the second output end of the half-bridge converter. Therefore, the output direct current is completely isolated from the alternating current, the live wire of the alternating current can be remotely controlled, and the safety is improved.

Description

Power supply circuit of temperature control liquid crystal screen controller

Technical Field

The utility model relates to a temperature controller technical field, especially a power supply circuit of temperature control LCD screen controller.

Background

Products such as temperature control beds and temperature control pads are usually controlled by a temperature controller, the temperature controller is provided with a control chip and a liquid crystal display, the liquid crystal display needs to be powered by a power supply device, and the power supply device converts 220V alternating current into 24V direct current. The existing power supply devices are adapters or switch power supplies, and alternating current parts and direct current parts of the existing power supply devices are not mutually isolated, so that the existing power supply devices have the possibility of breakdown, and therefore the safety is low. In addition, the live wire switch of the existing power supply device adopts a direct physical switch, needs to be controlled in a short distance, and is close to 220V alternating current, so that the safety of an operator is low.

SUMMERY OF THE UTILITY MODEL

In view of this, the present invention provides a power circuit of a temperature-controlled lcd controller, which can completely isolate the output dc power from the ac power, remotely control the live wire of the ac power, and improve the safety, so as to solve the above-mentioned problems.

A power supply circuit of a temperature control liquid crystal screen controller comprises an electronic switch circuit connected with a live wire L, a rectifier bridge connected with the electronic switch circuit and a zero line N, a filter capacitor C1 connected between a first output end and a second output end of the rectifier bridge, a start trigger circuit connected between the first output end and the second output end of the rectifier bridge, a half-bridge converter connected with the first output end, the second output end and the start trigger circuit of the rectifier bridge, and a magnetic core isolation step-down transformer TR connected with the first output end and the second output end of the half-bridge converter, wherein the magnetic core isolation step-down transformer TR is provided with an input winding, an output winding and a magnetic core penetrating through the input winding and the output winding, two ends of the input winding are respectively connected with the first output end and the second output end of the half-bridge converter, and the first end of the output winding is used as a direct current first output end, the second end is used as a direct current second output end.

Further, the electronic switch circuit comprises a Silicon Controlled Rectifier (SCR), a resistor R1, a resistor R2, a resistor R3, a control chip, a photoelectric coupler IOS and a fuse FU; the input end of the silicon controlled rectifier SCR is connected with a live wire L, the output end of the silicon controlled rectifier SCR is connected with the first end of the fuse FU, the control end of the silicon controlled rectifier SCR is connected with the input end through a resistor R1, the control end of the silicon controlled rectifier SCR is also connected with the first output end of the photoelectric coupler IOS, and the second output end of the photoelectric coupler IOS is connected with the output end of the silicon controlled rectifier SCR through a resistor R2; the power end of the photoelectric coupler IOS is connected with a direct current power supply VCC through a resistor R3, the control end is connected with the signal output end of the control chip, and the power end of the control chip is connected with the direct current power supply VCC.

Further, the rectifier bridge includes a first diode D1, a second diode D2, a third diode D3 and a fourth diode D4, an anode of the first diode D1 is connected to the second end of the fuse FU, and a cathode thereof is used as a first output end of the rectifier bridge and is connected to a cathode of the fourth diode D4; the cathode of the second diode D2 is connected to the anode of the first diode D1, and the anode is used as the second output terminal of the rectifier bridge and is connected to the anode of the third diode D3; the cathode of the third diode D3 is connected to the anode of the fourth diode D4 and to the neutral line N.

Further, the starting trigger circuit comprises a fifth diode D5, a sixth diode D6, a seventh diode D7, a capacitor C2, a capacitor C3, a resistor R4 and a diac DB; the anode of the fifth diode D5 is connected with the second output end of the rectifier bridge, and the cathode is connected with the anode of the sixth diode D6; the cathode of the sixth diode D6 is connected to the first output terminal of the rectifier bridge; the cathode of the seventh diode D7 is connected to the cathode of the fifth diode D5, and the anode is connected to the second output terminal of the rectifier bridge through the capacitor C3 and to the first output terminal of the rectifier bridge through the resistor R4; the capacitor C2 is connected to two ends of the resistor R4; a first terminal of the diac DB is connected to an anode of the seventh diode D7.

Further, the half-bridge converter comprises a first field effect transistor VT1, a second field effect transistor VT2, a capacitor C4, a capacitor C5, a capacitor C6, a capacitor C7, a resistor R5, a resistor R6, a resistor R7, an eighth diode D8, a ninth diode D9, a first winding L1, a second winding L2 and a third winding L3; the drain electrode of the first field effect transistor VT1 is connected with the first output end of the rectifier bridge, the source electrode is connected with the drain electrode of the second field effect transistor VT2, and the grid electrode is connected with the first end of the first winding L1 through a resistor R5; the first end of the capacitor C4 is connected with the drain of the first field effect transistor VT1, and the second end is connected with the source of the first field effect transistor VT 1; a second end of the first winding L1 is connected to the source of the first fet VT1 and to the anode of the eighth diode D8, and the cathode of the eighth diode D8 is connected to the gate of the first fet VT 1; the grid electrode of the second field effect transistor VT2 is connected with the second end of the bidirectional trigger diode DB through a resistor R6, and the source electrode is connected with the second output end of the rectifier bridge 20; a first end of the capacitor C5 is connected with the drain of the second field effect transistor VT2, and a second end is connected with the source of the second field effect transistor VT 2; a first end of the third winding L3 is connected with a second output end of the rectifier bridge, and a second end is connected with the gate of the second field effect transistor VT2 through a resistor R7; the anode of the ninth diode D9 is connected to the second output terminal of the rectifier bridge, and the cathode is connected to the gate of the second field effect transistor VT 2; a first end of the second winding L2 is connected with the source electrode of the first field effect transistor VT1 and the cathode of the seventh diode D7, and a second end is used as a first output end of the half-bridge converter; a first end of the capacitor C6 is connected with the drain of the first field effect transistor VT1, and a second end is connected with a first end of the capacitor C7; the second end of the capacitor C7 is connected with the second output end of the rectifier bridge; the node between the capacitor C6 and the capacitor C7 serves as the second output terminal of the half-bridge converter.

Further, the first winding L1, the second winding L2 and the third winding L3 are all wound on the same magnetic core, forming a self-excited driving transformer.

Compared with the prior art, the power circuit of the temperature control LCD panel controller of the utility model comprises an electronic switch circuit connected with a live wire L, a rectifier bridge connected with the electronic switch circuit and a zero line N, a filter capacitor C1 connected between a first output end and a second output end of the rectifier bridge, a start trigger circuit connected between the first output end and the second output end of the rectifier bridge, a half-bridge converter connected with the first output end, the second output end and the start trigger circuit of the rectifier bridge, and a magnetic core isolation step-down transformer TR connected with the first output end and the second output end of the half-bridge converter, wherein the magnetic core isolation step-down transformer TR is provided with an input winding, an output winding and a magnetic core passing through the input winding and the output winding, two ends of the input winding are respectively connected with the first output end and the second output end of the half-bridge converter, the first end of the output winding is used as a DC first output end, the second end is used as a direct current second output end. Therefore, the output direct current is completely isolated from the alternating current, the live wire of the alternating current can be remotely controlled, and the safety is improved.

Drawings

Embodiments of the present invention are described below with reference to the accompanying drawings, in which:

fig. 1 is a schematic circuit diagram of a power circuit of the temperature-controlled liquid crystal display controller provided by the present invention.

Detailed Description

The following describes in further detail specific embodiments of the present invention based on the drawings. It should be understood that the description herein of embodiments of the invention is not intended to limit the scope of the invention.

Referring to fig. 1, the power circuit of the temperature-controlled lcd panel controller provided by the present invention includes an electronic switch circuit 10 connected to an external live wire L, a rectifier bridge 20 connected to the electronic switch circuit 10 and an external zero line N, a filter capacitor C1 connected between two outputs of the rectifier bridge 20, a start trigger circuit 30 connected between two outputs of the rectifier bridge 20, a half-bridge converter 40 connected to two outputs of the rectifier bridge 20 and the start trigger circuit 30, and a magnetic core isolation step-down transformer TR connected to two outputs of the half-bridge converter 40. Because the liquid crystal screen has higher frequency and lower power, the magnetic core isolation step-down transformer TR can output a power supply signal with high frequency and low power.

The electronic switch circuit 10 realizes remote switch control on a live wire L, the rectifier bridge 20 is used for realizing rectification, the filter capacitor C1 is used for filtering, the starting trigger circuit 30 is used for triggering the half-bridge converter 40, the withstand voltage of a field effect tube in the half-bridge converter 40 is low, and the withstand voltage never exceeds the peak value of the human output voltage; the saturation voltage of the field effect transistor is also reduced to the minimum; the withstand voltage of the filter capacitor C1 can be reduced. The magnitude of the voltage applied to core isolation step-down transformer TR is only half of the original input voltage.

The electronic switch circuit 10 comprises a silicon controlled rectifier SCR, a resistor R1, a resistor R2, a resistor R3, a control chip U1, a photoelectric coupler IOS and a fuse FU.

The input and the live wire L of silicon controlled rectifier SCR are connected, and the output is connected with fuse FU's first end, and the control end passes through resistance R1 and is connected with the input, and the control end still is connected with optoelectronic coupler IOS's first output, and optoelectronic coupler IOS's second output passes through resistance R2 and is connected with silicon controlled rectifier SCR's output.

The power supply end of the photoelectric coupler IOS is connected with a direct current power supply VCC through a resistor R3, the control end is connected with the signal output end of the control chip U1, and the power supply end of the control chip U1 is connected with the direct current power supply VCC.

In this embodiment, the control chip U1 is a single chip microcomputer TSSOP 20A.

The rectifier bridge 20 includes a first diode D1, a second diode D2, a third diode D3, and a fourth diode D4. The anode of the first diode D1 is connected to the second end of the fuse FU, and the cathode is used as the first output terminal of the rectifier bridge 20 and is connected to the cathode of the fourth diode D4; the cathode of the second diode D2 is connected to the anode of the first diode D1, and the anode is used as the second output terminal of the rectifier bridge 20 and is connected to the anode of the third diode D3; the cathode of the third diode D3 is connected to the anode of the fourth diode D4 and to the neutral line N.

The first end of the filter capacitor C1 is connected to the first output terminal of the rectifier bridge 20, and the second end is connected to the second output terminal of the rectifier bridge 20.

The start trigger circuit 30 includes a fifth diode D5, a sixth diode D6, a seventh diode D7, a capacitor C2, a capacitor C3, a resistor R4, and a diac DB.

An anode of the fifth diode D5 is connected to the second output terminal of the rectifier bridge 20, a cathode thereof is connected to an anode of the sixth diode D6, and a cathode of the sixth diode D6 is connected to the first output terminal of the rectifier bridge 20.

The cathode of the seventh diode D7 is connected to the cathode of the fifth diode D5, the anode is connected to the second output terminal of the rectifier bridge 20 through the capacitor C3, and is connected to the first output terminal of the rectifier bridge 20 through the resistor R4, and the capacitor C2 is connected to both ends of the resistor R4. A first terminal of the diac DB is connected to an anode of the seventh diode D7.

The half-bridge converter 40 includes a first fet VT1, a second fet VT2, a capacitor C4, a capacitor C5, a capacitor C6, a capacitor C7, a resistor R5, a resistor R6, a resistor R7, an eighth diode D8, a ninth diode D9, a first winding L1, a second winding L2, and a third winding L3.

The drain of the first fet VT1 is connected to the first output terminal of the rectifier bridge 20, the source is connected to the drain of the second fet VT2, and the gate is connected to the first end of the first winding L1 via a resistor R5. The capacitor C4 has a first terminal connected to the drain of the first fet VT1 and a second terminal connected to the source of the first fet VT 1. The second end of the first winding L1 is connected to the source of the first fet VT1 and to the anode of the eighth diode D8, and the cathode of the eighth diode D8 is connected to the gate of the first fet VT 1.

The gate of the second fet VT2 is connected to the second terminal of the diac DB through a resistor R6, and the source is connected to the second output terminal of the rectifier bridge 20. The capacitor C5 has a first terminal connected to the drain of the second fet VT2 and a second terminal connected to the source of the second fet VT 2. The first end of the third winding L3 is connected to the second output terminal of the rectifier bridge 20, the second end is connected to the gate of the second fet VT2 through the resistor R7, the anode of the ninth diode D9 is connected to the second output terminal of the rectifier bridge 20, and the cathode is connected to the gate of the second fet VT 2.

A first end of the second winding L2 is connected to the source of the first fet VT1 and the cathode of the seventh diode D7, and a second end is used as a first output terminal of the half-bridge converter 40.

A first terminal of the capacitor C6 is connected to the drain of the first fet VT1, a second terminal is connected to a first terminal of the capacitor C7, and a second terminal of the capacitor C7 is connected to a second output terminal of the rectifier bridge 20. The node between the capacitor C6 and the capacitor C7 serves as the second output terminal of the half-bridge converter 40.

Step-down transformer TR is kept apart to magnetic core has input winding, output winding and passes input winding and output winding's magnetic core, and input winding's both ends are connected with half-bridge converter 40's first output and second output respectively, and output winding's first end is as the utility model provides a temperature control liquid crystal screen controller's power supply circuit's the first output OUT1 of direct current, the second end is as the utility model provides a temperature control liquid crystal screen controller's power supply circuit's direct current second output OUT 2.

The first winding L1, the second winding L2 and the third winding L3 are wound on the same iron core or magnetic core, and together form a self-excitation driving transformer. The self-excited driving transformer has enough exciting current flowing through it, which can ensure the normal switch action of the first field effect transistor VT1 and the second field effect transistor VT 2.

The positive half wave of the alternating current is delayed by the resistor R4 and the capacitor C3, and the second field effect transistor VT2 is conducted. The current is looped by a node between the capacitor C6 and the capacitor C7 through the input winding of the magnetic core isolation step-down transformer TR, the second winding L2 and the second field effect transistor VT 2. At this time, the second winding L2 senses the voltage with positive up, negative down, positive voltage, the first winding L1 senses the voltage with positive up, negative down, and the third winding L3 senses the voltage with positive up, negative down. This allows for the switching on of the first fet VT1 and the switching off of the second fet VT 2. When the first fet VT1 is turned on, current flows from the first fet VT1 through the second winding L2 and the input winding to the node between the capacitor C6 and the capacitor C7. The switching frequency of first field effect transistor VT1, second field effect transistor VT2 is promptly the utility model provides a control by temperature change LCD screen controller's power supply circuit's operating frequency.

Similarly, the working principle of the negative half-wave of the alternating current is similar.

Compared with the prior art, the power circuit of the temperature control LCD panel controller of the utility model comprises an electronic switch circuit 10 connected with a live wire L, a rectifier bridge 20 connected with the electronic switch circuit 10 and a zero line N, a filter capacitor C1 connected between the first output end and the second output end of the rectifier bridge 20, a start trigger circuit 30 connected between the first output end and the second output end of the rectifier bridge 20, a half-bridge converter 40 connected with the first output end, the second output end and the start trigger circuit 30, and a magnetic core isolation step-down transformer TR connected with the first output end and the second output end of the half-bridge converter 40, wherein the magnetic core isolation step-down transformer TR is provided with an input winding, an output winding and a magnetic core passing through the input winding and the output winding, the two ends of the input winding are respectively connected with the first output end and the second output end of the half-bridge converter 40, the first end of the output winding is used as a direct current first output end, and the second end of the output winding is used as a direct current second output end. Therefore, the output direct current is completely isolated from the alternating current, the live wire of the alternating current can be remotely controlled, and the safety is improved.

The above description is only for the preferred embodiment of the present invention and should not be construed as limiting the scope of the present invention, and any modification, equivalent replacement or improvement within the spirit of the present invention is encompassed by the claims of the present invention.

Claims

1. A power supply circuit of a temperature control liquid crystal screen controller is characterized in that: comprises an electronic switch circuit connected with a live wire L, a rectifier bridge connected with the electronic switch circuit and a zero line N, a filter capacitor C1 connected between the first output end and the second output end of the rectifier bridge, a starting trigger circuit connected between the first output end and the second output end of the rectifier bridge, and a half-bridge converter connected with the first output end, the second output end and the starting trigger circuit of the rectifier bridge, and a magnetic core isolation step-down transformer TR connected to both the first output end and the second output end of the half-bridge converter, the magnetic core isolation step-down transformer TR having an input winding, an output winding and a magnetic core passing through the input winding and the output winding, both ends of the input winding being connected to the first output end and the second output end of the half-bridge converter respectively, the first end of the output winding being a DC first output end, and the second end being a DC second output end.

2. The power supply circuit of the temperature-controlled liquid crystal panel controller according to claim 1, characterized in that: the electronic switch circuit comprises a Silicon Controlled Rectifier (SCR), a resistor R1, a resistor R2, a resistor R3, a control chip, a photoelectric coupler IOS and a fuse FU; the input end of the silicon controlled rectifier SCR is connected with a live wire L, the output end of the silicon controlled rectifier SCR is connected with the first end of the fuse FU, the control end of the silicon controlled rectifier SCR is connected with the input end through a resistor R1, the control end of the silicon controlled rectifier SCR is also connected with the first output end of the photoelectric coupler IOS, and the second output end of the photoelectric coupler IOS is connected with the output end of the silicon controlled rectifier SCR through a resistor R2; the power end of the photoelectric coupler IOS is connected with a direct-current power supply VCC through a resistor R3, the control end is connected with the signal output end of the control chip, and the power end of the control chip is connected with the direct-current power supply VCC.

3. The power supply circuit of the temperature-controlled liquid crystal panel controller according to claim 1, characterized in that: the rectifier bridge comprises a first diode D1, a second diode D2, a third diode D3 and a fourth diode D4, wherein the anode of the first diode D1 is connected with the second end of the fuse FU, and the cathode of the first diode D1 is used as the first output end of the rectifier bridge and is connected with the cathode of the fourth diode D4; the cathode of the second diode D2 is connected to the anode of the first diode D1, and the anode is used as the second output terminal of the rectifier bridge and is connected to the anode of the third diode D3; the cathode of the third diode D3 is connected to the anode of the fourth diode D4 and to the neutral line N.

4. The power supply circuit of the temperature-controlled liquid crystal panel controller according to claim 1, characterized in that: the starting trigger circuit comprises a fifth diode D5, a sixth diode D6, a seventh diode D7, a capacitor C2, a capacitor C3, a resistor R4 and a bidirectional trigger diode DB; the anode of the fifth diode D5 is connected with the second output end of the rectifier bridge, and the cathode is connected with the anode of the sixth diode D6; the cathode of the sixth diode D6 is connected to the first output terminal of the rectifier bridge; the cathode of the seventh diode D7 is connected to the cathode of the fifth diode D5, and the anode is connected to the second output terminal of the rectifier bridge through the capacitor C3 and to the first output terminal of the rectifier bridge through the resistor R4; the capacitor C2 is connected to two ends of the resistor R4; a first terminal of the diac DB is connected to an anode of the seventh diode D7.

5. The power supply circuit of the temperature-controlled liquid crystal panel controller according to claim 4, wherein: the half-bridge converter comprises a first field effect transistor VT1, a second field effect transistor VT2, a capacitor C4, a capacitor C5, a capacitor C6, a capacitor C7, a resistor R5, a resistor R6, a resistor R7, an eighth diode D8, a ninth diode D9, a first winding L1, a second winding L2 and a third winding L3; the drain electrode of the first field effect transistor VT1 is connected with the first output end of the rectifier bridge, the source electrode is connected with the drain electrode of the second field effect transistor VT2, and the grid electrode is connected with the first end of the first winding L1 through a resistor R5; the first end of the capacitor C4 is connected with the drain of the first field effect transistor VT1, and the second end is connected with the source of the first field effect transistor VT 1; a second end of the first winding L1 is connected to the source of the first fet VT1 and to the anode of the eighth diode D8, and the cathode of the eighth diode D8 is connected to the gate of the first fet VT 1; the grid electrode of the second field effect transistor VT2 is connected with the second end of the bidirectional trigger diode DB through a resistor R6, and the source electrode is connected with the second output end of the rectifier bridge 20; a first end of the capacitor C5 is connected with the drain of the second field effect transistor VT2, and a second end is connected with the source of the second field effect transistor VT 2; a first end of the third winding L3 is connected with a second output end of the rectifier bridge, and a second end is connected with the gate of the second field effect transistor VT2 through a resistor R7; the anode of the ninth diode D9 is connected to the second output terminal of the rectifier bridge, and the cathode is connected to the gate of the second field effect transistor VT 2; a first end of the second winding L2 is connected with the source electrode of the first field effect transistor VT1 and the cathode of the seventh diode D7, and a second end is used as a first output end of the half-bridge converter; a first end of the capacitor C6 is connected with the drain of the first field effect transistor VT1, and a second end is connected with a first end of the capacitor C7; the second end of the capacitor C7 is connected with the second output end of the rectifier bridge; the node between the capacitor C6 and the capacitor C7 serves as the second output terminal of the half-bridge converter.

6. The power supply circuit of the temperature-controlled liquid crystal panel controller according to claim 5, characterized in that: the first winding L1, the second winding L2 and the third winding L3 are wound on the same magnetic core to form a self-excitation driving transformer.