WO2020220449A1

WO2020220449A1 - Voltage conversion circuit

Info

Publication number: WO2020220449A1
Application number: PCT/CN2019/092725
Authority: WO
Inventors: 刘代进
Original assignee: 深圳市华星光电半导体显示技术有限公司
Priority date: 2019-04-30
Filing date: 2019-06-25
Publication date: 2020-11-05
Also published as: CN110086337A

Abstract

The present invention provides a voltage conversion circuit. The voltage conversion circuit comprises a control signal generation module and a voltage conversion module. An output end of the control signal generation module is electrically connected to a control end of the voltage conversion module. An input end of the voltage conversion module is accessed to a power supply voltage. During work, the control signal generation module transmits a control signal from the output end to the control end of the voltage conversion module, and the voltage conversion module converts the power supply voltage under the control of the control signal to generate a constant voltage low potential and outputs the constant voltage low potential from the output end. According to the present invention, the driving capacity is high, and stable constant voltage low potential can be outputted, so that a leakage current in a GOA circuit is effectively reduced.

Description

Voltage conversion circuit

Technical field

The present invention relates to the field of display technology, and in particular to a voltage conversion circuit.

Background technique

Liquid Crystal Display (LCD) has many advantages such as thin body, power saving, and no radiation, and has been widely used. Such as: LCD TV, mobile phone, personal digital assistant (PDA), digital camera, computer screen or notebook computer screen, etc., occupy a dominant position in the field of flat panel display.

GOA (Gate Driver on Array) technology is the array substrate row drive technology, which uses the thin film transistor (Thin Film Transistor, TFT) liquid crystal display array process to fabricate the gate scanning drive circuit on the thin film transistor array substrate to achieve progressive scanning. The driving method has the advantages of reducing production costs and realizing the narrow frame design of the panel, and is used by a variety of displays. The GOA circuit has two basic functions: the first is to output the gate scan driving signal, which drives the gate line in the panel, and turns on the TFT in the display area to charge the pixels; the second is the shift register function, which acts as a gate After the output of the pole scan drive signal is completed, the next gate scan drive signal is output through clock control, and is passed on in sequence. GOA technology can reduce the bonding process of external chips (IC), which has the opportunity to increase production capacity and reduce product costs, and it can make LCD panels more suitable for manufacturing display products with narrow bezels.

In the prior art, in order to pull down and maintain the key nodes in the GOA circuit and the scan signal output by the GOA circuit, and reduce the leakage current of the thin film transistor that pulls down the scan signal, it is necessary to transmit the key node low potential and scan to the GOA circuit. Signal low potential, the key node low potential is lower than the scan signal low potential (generally the difference between the two is more than 2V). Among them, the low potential of the scan signal is generated by the system low potential lower than the low potential of the scan signal in conjunction with a voltage stabilizing circuit, and the low potential of the key node is generated by the system low potential. Please refer to FIG. 1, which is a circuit diagram of an existing voltage conversion circuit for generating a low potential of a scan signal. The voltage conversion circuit includes a power management chip (PMIC) 100, a transistor T10, a first resistor R10, a diode D10, a capacitor C10, The second resistor R20 and the level conversion unit 200. The output terminal of the power management chip 100 is electrically connected to the emitter of the transistor T10 to output the system low potential VGL. The base of the transistor T10 is electrically connected to the anode of the diode D10, and the collector is electrically connected to the input end of the level conversion unit 200 to output the scan signal low potential Vssg to it. The level conversion unit 200 converts the scan signal low potential Vssg. Output to GOA circuit. The two ends of the first resistor R10 are respectively electrically connected to the base and the emitter of the transistor T10. The cathode of the diode D10 is grounded. One end of the capacitor C10 is electrically connected to the collector of the transistor T10, and the other end is grounded. Two ends of the second resistor R20 are respectively electrically connected to two ends of the capacitor C10. The driving force of this voltage conversion circuit is insufficient. In actual work, the scan signal low potential Vssg will leak to the system low potential VGL, so that the scan signal low potential Vssg is actually controlled by the constant voltage low potential VGL, resulting in the key node low potential and scan signal A sufficient voltage difference cannot be guaranteed between low potentials, and thus the leakage current of the thin film transistor in the GOA circuit cannot be effectively reduced. The above-mentioned problem is usually solved by changing the resistance of the second resistor R20, but the effect is poor.

technical problem

The purpose of the present invention is to provide a voltage conversion circuit with high driving force and capable of outputting a stable constant voltage and low potential, so as to effectively reduce the leakage current in the GOA circuit.

Technical solutions

In order to achieve the above objective, the present invention provides a voltage conversion circuit, including a control signal generation module and a voltage conversion module;

The output terminal of the control signal generating module is electrically connected to the control terminal of the voltage conversion module to transmit the control signal to the control terminal of the voltage conversion module;

The input terminal of the voltage conversion module is connected to the power supply voltage for converting the power supply voltage under the control of the control signal to generate a constant voltage low potential, and the output terminal of the voltage conversion module outputs a constant voltage low potential.

The voltage conversion module includes a switch unit, an inductor, a diode, and a capacitor; the control terminal of the switch unit is the control terminal of the voltage conversion module, the first terminal is the input terminal of the voltage conversion module, and the second terminal is electrically connected to one end of the inductor The switch unit is used to conduct or disconnect the first end and the second end of the switch unit under the control of the control signal; the other end of the inductor is grounded; the cathode of the diode is electrically connected to one end of the inductor, and the anode is The output terminal of the voltage conversion module; one end of the capacitor is electrically connected to the anode of the diode, and the other end is grounded.

The voltage conversion module further includes a resistor; both ends of the resistor are electrically connected to both ends of the capacitor.

The diode is a Schottky diode.

The maximum repeated peak reverse voltage of the diode is 40V, and the maximum average conversion current is 2A.

The switching unit is a field effect tube; the gate of the field effect tube is the control end of the switching unit, and the source and drain are the first end and the second end of the switching unit, respectively.

The control signal generating module is a power management chip.

The output terminal of the voltage conversion module is used to electrically connect the GOA circuit; the constant voltage low potential is the scan signal low potential.

The constant voltage low potential is -5V~-6V.

The power supply voltage is greater than zero.

Beneficial effect

The beneficial effects of the present invention: the voltage conversion circuit of the present invention includes a control signal generation module and a voltage conversion module. The output end of the control signal generation module is electrically connected to the control end of the voltage conversion module, and the input end of the voltage conversion module is connected to the power supply voltage. When working, the control signal generation module transmits control signals from its output terminal to the control terminal of the voltage conversion module. The voltage conversion module converts the power supply voltage under the control of the control signal to generate a constant voltage and low potential, which is output by its output terminal. Strong, can output a stable constant voltage low potential to effectively reduce the leakage current in the GOA circuit.

Description of the drawings

In order to further understand the features and technical content of the present invention, please refer to the following detailed description and accompanying drawings of the present invention. However, the accompanying drawings are only provided for reference and illustration and are not used to limit the present invention.

In the attached picture,

FIG. 1 is a schematic diagram of the structure of an existing voltage conversion circuit;

Figure 2 is a schematic diagram of the structure of the voltage conversion circuit of the present invention.

Embodiments of the invention

In order to further explain the technical means adopted by the present invention and its effects, the following describes in detail the preferred embodiments of the present invention and the accompanying drawings.

Please refer to FIG. 2, the present invention provides a voltage conversion circuit including a control signal generation module 10 and a voltage conversion module 20.

The output terminal of the control signal generating module 10 is electrically connected to the control terminal of the voltage conversion module 20 for transmitting control signals from the output terminal to the control terminal of the voltage conversion module 20.

The input terminal of the voltage conversion module 20 is connected to the power supply voltage VCC for converting the power supply voltage VCC under the control of the control signal to generate a constant voltage low potential VSSG, and the output terminal of the voltage conversion module 20 outputs a constant voltage low The potential VSSG.

Specifically, the voltage conversion module 20 includes a switch unit 21, an inductor L1, a diode D1, and a capacitor C1. The control terminal of the switch unit 21 is the control terminal of the voltage conversion module 20, the first terminal is the input terminal of the voltage conversion module 20, the second terminal is electrically connected to one end of the inductor L1, and the switch unit 21 is used for controlled signals The first end and the second end are turned on or off. The other end of the inductor L1 is grounded. The cathode of the diode D1 is electrically connected to one end of the inductor L1 and the anode is the output terminal of the voltage conversion module 20. One end of the capacitor C1 is electrically connected to the anode of the diode D1, and the other end is grounded.

Further, in the embodiment shown in FIG. 2, the voltage conversion module 20 further includes a resistor R1. The two ends of the resistor R1 are electrically connected to the two ends of the capacitor C1, respectively.

Preferably, the diode D1 is a Schottky diode.

More preferably, the maximum repeated peak reverse voltage of the diode D1 is 40V, and the maximum average conversion current is 2A.

Specifically, in the embodiment shown in FIG. 2, the switch unit 21 is a field effect transistor Q1. The gate of the field effect transistor Q1 is the control terminal of the switch unit 21, and the source and drain are the first terminal and the second terminal of the switch unit 21, respectively. Of course, in other embodiments of the present invention, the switch unit 21 can also be a common switch unit such as thin film transistors, which will not affect the implementation of the present invention.

Preferably, the control signal generating module 10 is a power management chip.

Specifically, the output terminal of the voltage conversion module 20 is used to electrically connect the GOA circuit 30. The constant voltage low potential VSSG is the scan signal low potential, that is, the constant voltage low potential is connected to the pull-down module and pull-down maintenance module of each level of GOA unit in the GOA circuit 30, for pull-down and pull-down to maintain each level of GOA The scan signal of the unit.

Preferably, the constant voltage low potential VSSG is -5V to -6V.

Specifically, the power supply voltage VCC is greater than zero.

It should be noted that when the voltage conversion circuit of the present invention is working, the control signal generation module 10 transmits a control signal from its output terminal to the control terminal of the voltage conversion module 20, and the voltage conversion module 20 controls the power supply voltage VCC under the control of the control signal. Converted to generate a constant voltage low potential VSSG and output to the GOA circuit from its output end. Compared with the prior art voltage conversion circuit for generating scan signal low potential, the driving capability of the voltage conversion circuit of the present invention is improved by one Order of magnitude, strong driving capability, capable of outputting a stable constant voltage low potential VSSG, effectively avoiding the leakage between the scan signal low potential and the system low potential in the prior art, which causes the system low potential to pull down the scan signal low potential, effectively ensuring the The voltage difference between the constant voltage low potential VSSG used as the scanning signal and the low potential used to pull down and maintain the key nodes in the GOA circuit, thereby effectively reducing the leakage current in the GOA circuit and improving the reliability of the GOA circuit.

In summary, the voltage conversion circuit of the present invention includes a control signal generation module and a voltage conversion module. The output end of the control signal generation module is electrically connected to the control end of the voltage conversion module, and the input end of the voltage conversion module is connected to the power supply voltage to work When the control signal generation module transmits the control signal from its output terminal to the control terminal of the voltage conversion module, the voltage conversion module converts the power supply voltage under the control of the control signal to generate a constant voltage and low potential, which is output by its output terminal, with strong driving ability , It can output a stable constant voltage low potential to effectively reduce the leakage current in the GOA circuit.

As mentioned above, for those of ordinary skill in the art, various other corresponding changes and modifications can be made according to the technical solutions and technical ideas of the present invention, and all these changes and modifications shall fall within the protection scope of the claims of the present invention. .

Claims

A voltage conversion circuit includes a control signal generation module and a voltage conversion module;

The output terminal of the control signal generating module is electrically connected to the control terminal of the voltage conversion module to transmit the control signal to the control terminal of the voltage conversion module;

The input terminal of the voltage conversion module is connected to the power supply voltage for converting the power supply voltage under the control of the control signal to generate a constant voltage low potential, and the output terminal of the voltage conversion module outputs a constant voltage low potential.
The voltage conversion circuit of claim 1, wherein the voltage conversion module includes a switch unit, an inductor, a diode, and a capacitor; the control terminal of the switch unit is the control terminal of the voltage conversion module, and the first terminal is the voltage conversion module The second terminal is electrically connected to one end of the inductor, and the switch unit is used to conduct or disconnect the first terminal and the second terminal under the control of the control signal; the other end of the inductor is grounded; The cathode of the diode is electrically connected to one end of the inductor, and the anode is the output end of the voltage conversion module; one end of the capacitor is electrically connected to the anode of the diode, and the other end is grounded.
3. The voltage conversion circuit of claim 2, wherein the voltage conversion module further comprises a resistor; both ends of the resistor are electrically connected to both ends of the capacitor.
3. The voltage conversion circuit of claim 2, wherein the diode is a Schottky diode.
8. The voltage conversion circuit of claim 4, wherein the maximum repetitive peak reverse voltage of the diode is 40V, and the maximum average conversion current is 2A.
3. The voltage conversion circuit of claim 2, wherein the switch unit is a field effect tube; the gate of the field effect tube is the control end of the switch unit, and the source and drain are the first end and the drain of the switch unit, respectively. The second end.
8. The voltage conversion circuit of claim 1, wherein the control signal generating module is a power management chip.
3. The voltage conversion circuit of claim 1, wherein the output terminal of the voltage conversion module is used to electrically connect to the GOA circuit; the constant voltage low potential is the scan signal low potential.
8. The voltage conversion circuit of claim 8, wherein the constant voltage low potential is -5V to -6V.
3. The voltage conversion circuit of claim 1, wherein the power supply voltage is greater than zero.