WO2020062496A1

WO2020062496A1 - Driving circuit

Info

Publication number: WO2020062496A1
Application number: PCT/CN2018/116121
Authority: WO
Inventors: 李文芳
Original assignee: 深圳市华星光电技术有限公司
Priority date: 2018-09-27
Filing date: 2018-11-19
Publication date: 2020-04-02
Also published as: CN109119042A; CN109119042B

Abstract

A driving circuit comprises a linear regulator (2), an amplifier module (3), a comparator module (4), and a delay module (5). When a stable voltage received at an input terminal (51) of the delay module (5) is less than a preset voltage, a voltage comparator (44) of the comparator module (4) is turned off, and when the stable voltage received at the input terminal (51) of the delay module (5) is equal to or greater than the preset voltage, the voltage comparator (44) is turned on, thereby preventing a level shifter from having an abnormal output.

Description

Drive circuit

Technical field

The present invention relates to a driving circuit, and more particularly to a driving circuit applied to a level shifter.

Background technique

The active matrix liquid crystal display includes a thin film transistor (TFT) as a switching element in each pixel. The active matrix liquid crystal display can be made smaller than a cathode ray tube (CRT), and thus can be applied to display units of portable information equipment, office equipment, computers, and the like. In addition, the active matrix liquid crystal display can be applied to a television, and thus quickly replaces a cathode ray tube.

The liquid crystal display includes a liquid crystal display panel, a backlight unit that provides light to the liquid crystal display panel, and a data driving circuit for supplying a data voltage to a data line of the liquid crystal display panel. A gate driving circuit of a gate line (ie, a scanning line) of the panel, and a timing controller for controlling an operation timing of the data driving circuit, the gate driving circuit, and the like. The liquid crystal display further includes a power supply device for generating a data voltage of the liquid crystal display panel, an on-voltage VGH and an off-voltage VGL of the TFT, and a power supply voltage VCC of the data driving circuit and the gate driving circuit and the timing controller.

The power supply unit of the liquid crystal display is integrated into an integrated circuit (IC). Hereinafter, an IC in which a power supply device is embedded is referred to as a power 1C. When the power switch of the liquid crystal display is turned on, the input voltage Vin of the power IC rises.

LCD power ICs have under voltage lockout lock out, UVLO) module. When the input voltage Vin of the power IC reaches a previously predetermined level of the UVLO module, the power IC generates an internal logic voltage VL and starts the internal logic. When the internal logic is activated, the power IC generates an output voltage Vout.

The gate driving circuit of the liquid crystal display includes a level shifter and a shift register. With the development of the gate-in-panel (GIP) process technology, a shift register can be formed on a substrate together with a TFT array, and a TFT array of a liquid crystal display panel is formed on the substrate. The level shifter may be formed on a printed circuit board (PCB), which is electrically connected to a substrate of the liquid crystal display panel. The level shifter outputs a clock signal swinging between the gate high voltage VGH and the gate low voltage VGL under the control of the timing controller. The voltage of the gate high voltage VGH is set to be equal to or greater than a threshold voltage of a TFT included in a TFT array of a liquid crystal display panel. The voltage of the gate low voltage VGL is set to be smaller than a threshold voltage of a TFT included in a TFT array of a liquid crystal display panel. The shift register sequentially shifts clock signals received from the level shifter, and sequentially supplies gate pulses to the gate lines of the liquid crystal display panel.

However, when the rise time of the gate high voltage VGH is too fast, that is, the voltage of the gate high voltage VGH has not reached the correct voltage, so that the voltage output to the UVLO module will drop, resulting in an abnormal output of the level shifter.

technical problem

An object of the present invention is to provide a driving circuit that utilizes the design of a delay module to ensure that the voltage comparator does not start to operate until the voltage reaches a preset voltage value, so as to avoid abnormal output of the level shifter.

Technical solutions

To solve the above problems, the technical solution provided by the present invention is as follows:

To achieve the foregoing object of the present invention, an embodiment of the present invention provides a driving circuit. The driving circuit includes a linear regulator, an amplifier module, a comparator module, and a delay module. The linear regulator has an input terminal. And an output terminal, wherein the input terminal of the linear regulator is electrically connected to a conducting voltage, the linear regulator is configured to enable the output terminal to output a stable voltage; the amplifier module has two input terminals and An output terminal, wherein one input terminal of the amplifier module is electrically connected to the output terminal of the linear regulator, the output terminal of the amplifier module is fed back to the other input terminal of the amplifier module, and the amplifier module is configured The stable voltage is received by the linear regulator. The stable voltage is reduced by the amplifier module, and an adjustment voltage is output from the output terminal of the amplifier module. The comparator module has two input terminals. And an output terminal, wherein an input terminal of the comparator module is electrically connected to the turn-on voltage, and another of the comparator module is The input terminal is configured to receive the adjustment voltage, the output terminal is electrically connected to a circuit to be driven, and the comparator module is configured to compare the on-voltage with the adjustment voltage, and then the An output terminal of the comparator module outputs a driving voltage to drive the circuit to be driven; the delay module has an input terminal and an output terminal, wherein the input terminal of the delay module is electrically connected to the linear regulator. An output terminal, the comparator module is configured to receive an activation signal output from the output terminal of the delay module; when the stable voltage received by the input terminal of the delay module is less than a set voltage, the activation signal is A low level causes the voltage comparator in the comparator module to be turned off. When the stable voltage received by the input terminal of the delay module is equal to or greater than the set voltage, the activation signal is a high voltage Level so that the voltage comparator is turned on, and the output terminal of the voltage comparator is connected to the circuit to be driven.

In an embodiment of the present invention, the comparator module has the voltage comparator, a first resistor and a second resistor, wherein two terminals of the second resistor are electrically connected to the on-voltage and A first terminal of the voltage comparator and two terminals of the first resistor are electrically connected to the first terminal of the voltage comparator and ground, respectively, wherein the first terminal of the voltage comparator is configured to receive the voltage comparator. The divided voltage of an input terminal of the comparator module, a second terminal of the voltage comparator is another input terminal of the comparator module, and an output terminal of the voltage comparator is an output of the comparator module end.

In an embodiment of the present invention, a first terminal of the voltage comparator is a non-inverting output terminal, a second terminal of the voltage comparator is an inverting input terminal, and an output terminal of the voltage comparator is connected To the under-voltage lockout module of the circuit to be driven.

In an embodiment of the present invention, a ratio of a resistance value of the first resistor to a resistance value of the second resistor is 1:29.

In an embodiment of the present invention, when a voltage at the first terminal of the voltage comparator is greater than a voltage at the second terminal of the voltage comparator, and the on-voltage is greater than 16V, the voltage of the voltage comparator The output terminal outputs a high level.

In an embodiment of the present invention, the amplifier module has an operational amplifier, a third resistor, a fourth resistor, and a fifth resistor, wherein a first end of the operational amplifier is an input of the amplifier module. Two ends of the fifth resistor are electrically connected to a second end and an output end of the operational amplifier, respectively, and two ends of the fourth resistor are electrically connected to the second end of the operational amplifier and an output end, respectively. The third resistor, and two terminals of the third resistor are electrically connected to the second terminal of the voltage comparator and ground respectively.

In an embodiment of the present invention, a ratio of a resistance value of the third resistor to a resistance value of the fourth resistor is 1: 5.

In an embodiment of the present invention, a first terminal of the operational amplifier is a non-inverting output terminal, and a second terminal of the operational amplifier is an inverting input terminal.

In an embodiment of the invention, the set voltage is 0.5V.

In an embodiment of the invention, the on-voltage is a gate high voltage output by a level shifter under the control of a timing controller.

To achieve the foregoing object of the present invention, an embodiment of the present invention provides a driving circuit. The driving circuit includes a linear regulator, an amplifier module, a comparator module, and a delay module. The linear regulator has an input terminal. And an output terminal, wherein the input terminal of the linear regulator is electrically connected to a conducting voltage, the linear regulator is configured to enable the output terminal to output a stable voltage; the amplifier module has two input terminals and An output terminal, wherein one input terminal of the amplifier module is electrically connected to the output terminal of the linear regulator, the output terminal of the amplifier module is fed back to the other input terminal of the amplifier module, and the amplifier module is configured The stable voltage is received by the linear regulator. The stable voltage is reduced by the amplifier module, and an adjustment voltage is output from the output terminal of the amplifier module. The comparator module has two input terminals. And an output terminal, wherein an input terminal of the comparator module is electrically connected to the turn-on voltage, and another of the comparator module is The input terminal is configured to receive the adjustment voltage, the output terminal is electrically connected to a circuit to be driven, and the comparator module is configured to compare the on-voltage with the adjustment voltage, and then the An output terminal of the comparator module outputs a driving voltage to drive the circuit to be driven; the delay module has an input terminal and an output terminal, wherein the input terminal of the delay module is electrically connected to the linear regulator. An output terminal, the comparator module is configured to receive an activation signal output from the output terminal of the delay module; when the stable voltage received by the input terminal of the delay module is less than a set voltage, the activation signal is A low level causes the voltage comparator in the comparator module to be turned off. When the stable voltage received by the input terminal of the delay module is equal to or greater than the set voltage, the activation signal is a high voltage Level so that the voltage comparator is turned on.

In an embodiment of the invention, the set voltage is 0.5V.

Beneficial effect

The beneficial effect of the present invention is: through the design of the delay module, it can be ensured that the voltage comparator is turned on only after the voltage of the second terminal of the voltage comparator is equal to or greater than a voltage value, thereby ensuring the voltage After the voltage at the second terminal of the comparator reaches the voltage value, the voltage comparator starts to work to avoid abnormal output of the level shifter.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to more clearly explain the embodiments or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings in the following description are merely inventions. For some embodiments, for those skilled in the art, other drawings can be obtained based on these drawings without paying creative labor.

FIG. 1 is a schematic diagram of a preferred embodiment of the driving circuit of the present invention.

Best Mode of the Invention

The liquid crystal display module provided by the embodiments of the present invention has been described in detail above. Specific examples are used herein to explain the principles and implementation of the present invention. The description of the above embodiments is only used to help understand the present invention. At the same time, for those skilled in the art, according to the idea of the present invention, there will be changes in the specific implementation and scope of application. In summary, the content of this description should not be construed as a limitation on the present invention. The following descriptions of the embodiments are made with reference to additional illustrations to illustrate specific embodiments in which the present invention can be implemented. The directional terms mentioned in the present invention, such as [up], [down], [front], [rear], [left], [right], [in], [out], [side], etc., are for reference only. The direction of the attached schema. Therefore, the directional terms used are for explaining and understanding the present invention, but not for limiting the present invention. In the figure, similarly structured units are denoted by the same reference numerals.

Please refer to FIG. 1, which is a schematic diagram of a preferred embodiment of a driving circuit of the present invention. The driving circuit includes a linear regulator 2, an amplifier module 3, a comparator module 4, and a delay module 5. The present invention will explain in detail the detailed structure, assembly relationship, and operation principle of the above components of the embodiments. .

Continuing to refer to FIG. 1, the linear regulator 2 has an input terminal 21 and an output terminal 22, wherein the input terminal 21 of the linear regulator 2 is electrically connected to a conducting voltage VGH, and the linear adjustment The device 2 is configured to enable the output terminal 22 to output a stable voltage, for example, a 3V voltage. In this embodiment, the on-voltage VGH is a gate high voltage output by a level shifter (not shown) under the control of a timing controller.

Continuing to refer to FIG. 1, the amplifier module 3 has two input terminals 31, 32 and an output terminal 33. One input terminal 31 of the amplifier module 3 is electrically connected to the output terminal 22 of the linear regulator 2. An output terminal 33 of the amplifier module 3 is fed back to another input terminal 32 of the amplifier module 3, and the amplifier module 3 is configured to receive the stable voltage output by the linear regulator 2, and the stable The voltage is reduced by the amplifier module 3, and an adjustment voltage is output from the output terminal 33 of the amplifier module 3.

Continuing to refer to FIG. 1, further, the amplifier module 3 has an operational amplifier 34, a third resistor R3, a fourth resistor R4, and a fifth resistor R5, wherein a first A terminal is an input terminal 31 of the amplifier module 3, an output terminal of the operational amplifier 34 is an output terminal 33 of the amplifier module 3, and two terminals of the fifth resistor R5 are electrically connected to the operational amplifier 34, respectively. A second terminal of the operational amplifier 34 and two terminals of the fourth resistor R4 are electrically connected to the second terminal of the operational amplifier 34 and the third resistor R3, and the third resistor Two terminals of R3 are electrically connected to the comparator module 4 and ground respectively. In this embodiment, a ratio of a resistance value of the third resistor R3 to a resistance value of the fourth resistor R4 is 1: 5, for example, the third resistor R3 is 1 ohm, and the fourth resistor The resistance R4 is 5 ohms. The adjusted voltage is output to the comparator module 4 through a divided voltage of the third resistor R3 and the fourth resistor R4. In addition, a first terminal of the operational amplifier 34 is a non-inverting output terminal, and a second terminal of the operational amplifier 34 is an inverting input terminal.

Continuing to refer to FIG. 1, the comparator module 4 has two input terminals 41, 42 and an output terminal 43. An input terminal 41 of the comparator module 4 is electrically connected to the on-voltage VGH. The other input terminal of the comparator module 42 is electrically connected to the third resistor R3 and the fourth resistor R4 of the amplifier module 3, and the output terminal 43 is electrically connected to a circuit to be driven (not shown). In this embodiment, the output terminal 43 of the voltage comparator 44 is connected to an under-voltage lockout module (not shown) of the circuit to be driven, and the comparator module 4 is configured to connect the on-voltage VGH and the adjusted voltage after dividing by the third resistor R3 and the fourth resistor R4 are compared, and then a driving voltage UVLO is output from the output terminal of the comparator module 4 to drive the under voltage Press the lock module.

Continuing to refer to FIG. 1, further, the comparator module 4 has a voltage comparator 44, a first resistor R1 and a second resistor R2, wherein two ends of the second resistor R2 are electrically connected respectively. The on-voltage VGH and a first terminal of the voltage comparator 44, and two terminals of the first resistor R1 are electrically connected to the first terminal of the voltage comparator 44 and ground, respectively, wherein the voltage comparison A first terminal of the comparator 44 is configured to receive a divided voltage from an input terminal 41 of the comparator module 4 through the first resistor R1 and the second resistor R2, and a second terminal of the voltage comparator 44 It is the other input terminal 42 of the comparator module 4, and an output terminal of the voltage comparator 44 is the output terminal 43 of the comparator module 4. In this embodiment, a first terminal of the voltage comparator 44 is a non-inverting output terminal, and a second terminal of the voltage comparator 44 is an inverting input terminal. In the implementation process, when a voltage at the first terminal of the voltage comparator 44 is greater than a voltage at the second terminal of the voltage comparator 44 and the on-voltage VGH is greater than 16V, the voltage comparator 44 The output terminal outputs a high level. In addition, a ratio of a resistance value of the first resistor R1 to a resistance value of the second resistor R2 is 1:29. For example, the first resistor R1 is 1 ohm, and the second resistor R2 is 29 ohms.

Continuing to refer to FIG. 1, the delay module 5 has an input terminal 51 and an output terminal 52. The input terminal 51 of the delay module 5 is electrically connected to the output terminal 22 of the linear regulator 2. The voltage comparator 44 of the comparator module 4 is configured to receive an activation signal output from the output terminal 52 of the delay module 5. The delay module 5 is configured to generate the activation signal according to the stable voltage of the output terminal 22 of the linear regulator 2 to enable or disable the voltage comparator 44.

According to the above structure, when the stable voltage received by the input terminal 51 of the delay module 5 is less than a set voltage, the activation signal is a low level, so that the voltage comparator 44 is turned off. The stable voltage received by the input terminal 51 of the delay module 5 is equal to or greater than the set voltage, and the activation signal is a high level, so that the voltage comparator 44 is turned on. In this embodiment, the set voltage is 0.5V. Further, when the on-voltage VGH rises too fast, the voltage of the first terminal of the voltage comparator 44 is greater than the voltage of the second terminal of the voltage comparator 44 and the voltage of the voltage comparator 44 When the voltage at the two terminals is less than 0.5V, the activation signal is at a low level, the voltage comparator 44 is turned off, and the driving voltage UVLO is at a low level, so that the level shifter has no output signal. When the voltage of the second terminal of the voltage comparator 44 is equal to or greater than 0.5V, the activation signal is at a high level, and the voltage comparator 44 is turned on. At this time, the voltage of the first terminal of the voltage comparator 44 is greater than The voltage of the second terminal of the voltage comparator 44, the voltage of the on-voltage VGH is greater than 16V, and the driving voltage UVLO is at a high level, so that the level shifter normally outputs a signal.

As described above, through the design of the delay module 5, it is possible to ensure that the voltage of the second terminal of the voltage comparator 44 is equal to or greater than a voltage value, for example, 0.5V, and the voltage comparator 44 is turned on. It can be ensured that after the voltage of the second terminal of the voltage comparator 44 reaches the voltage value, for example, 0.5V, the voltage comparator 44 starts to work, so as to avoid abnormal output of the level shifter.

The present invention has been described by the above related embodiments, but the above embodiments are merely examples for implementing the present invention. It must be noted that the disclosed embodiments do not limit the scope of the invention. On the contrary, modifications and equal arrangements included in the spirit and scope of the claims are all included in the scope of the present invention.

Claims

A driving circuit, characterized in that the driving circuit includes:

A linear regulator having an input terminal and an output terminal, wherein the input terminal of the linear regulator is electrically connected to a conducting voltage, and the linear regulator is configured to enable the output terminal to output a stable voltage;

An amplifier module has two input terminals and an output terminal, wherein one input terminal of the amplifier module is electrically connected to the output terminal of the linear regulator, and the output terminal of the amplifier module is fed back to the other of the amplifier module. An input terminal, the amplifier module is configured to receive the stable voltage output by the linear regulator, the stable voltage is reduced by the amplifier module, and an adjustment voltage is output from the output terminal of the amplifier module;

A comparator module has two input terminals and an output terminal, wherein one input terminal of the comparator module is electrically connected to the on-voltage, and the other input terminal of the comparator module is configured to receive the adjustment. Voltage, the output terminal is electrically connected to a circuit to be driven, and the comparator module is configured to compare the on-voltage and the adjustment voltage, and then an output terminal of the comparator module outputs a A driving voltage to drive the circuit to be driven; and

A delay module has an input terminal and an output terminal, wherein the input terminal of the delay module is electrically connected to the output terminal of the linear regulator, and the comparator module is configured to receive the output of the output terminal of the delay module. An activation signal;

When the stable voltage received by the input of the delay module is less than a set voltage, the activation signal is a low level, so that the voltage comparator in the comparator module is turned off. The stable voltage received at the input terminal is equal to or greater than the set voltage, and the activation signal is a high level, so that the voltage comparator is turned on;

An output terminal of the voltage comparator is connected to the circuit to be driven.
The driving circuit according to claim 1, wherein the comparator module has the voltage comparator, a first resistor, and a second resistor, and two ends of the second resistor are electrically connected to the respective terminals. The on-voltage and a first terminal of the voltage comparator, and two terminals of the first resistor are electrically connected to the first terminal of the voltage comparator and ground, respectively, wherein the first terminal of the voltage comparator Configured to receive a divided voltage from an input terminal of the comparator module, a second terminal of the voltage comparator is the other input terminal of the comparator module, and an output terminal of the voltage comparator is the Comparator output.
The driving circuit according to claim 2, wherein a first terminal of the voltage comparator is a non-inverting output terminal, a second terminal of the voltage comparator is an inverting input terminal, and the voltage comparison The output terminal of the device is connected to the under-voltage lockout module of the circuit to be driven.
The driving circuit according to claim 2, wherein a ratio of a resistance value of the first resistor to a resistance value of the second resistor is 1:29.
The driving circuit according to claim 2, wherein when a voltage at a first terminal of the voltage comparator is greater than a voltage at a second terminal of the voltage comparator, and the on-voltage is greater than 16V, so The output terminal of the voltage comparator outputs a high level.
The driving circuit according to claim 2, wherein the amplifier module has an operational amplifier, a third resistor, a fourth resistor, and a fifth resistor, wherein a first end of the operational amplifier is The input terminal of the amplifier module, two terminals of the fifth resistor are electrically connected to a second terminal and an output terminal of the operational amplifier, respectively, and two terminals of the fourth resistor are electrically connected to the operational amplifier, respectively. A second terminal and the third resistor, and two terminals of the third resistor are electrically connected to the second terminal of the voltage comparator and ground, respectively.
The driving circuit according to claim 6, wherein a ratio of a resistance value of the third resistor to a resistance value of the fourth resistor is 1: 5.
The driving circuit according to claim 6, wherein the first terminal of the operational amplifier is a non-inverting output terminal, and the second terminal of the operational amplifier is an inverting input terminal.
The driving circuit according to claim 1, wherein the set voltage is 0.5V.
The driving circuit according to claim 1, wherein the on-voltage is a gate high voltage output by a level shifter under the control of a timing controller.
A driving circuit, characterized in that the driving circuit includes:

A linear regulator having an input terminal and an output terminal, wherein the input terminal of the linear regulator is electrically connected to a conducting voltage, and the linear regulator is configured to enable the output terminal to output a stable voltage;

An amplifier module has two input terminals and an output terminal, wherein one input terminal of the amplifier module is electrically connected to the output terminal of the linear regulator, and the output terminal of the amplifier module is fed back to the other of the amplifier module. An input terminal, the amplifier module is configured to receive the stable voltage output by the linear regulator, the stable voltage is reduced by the amplifier module, and an adjustment voltage is output from the output terminal of the amplifier module;

A comparator module has two input terminals and an output terminal, wherein one input terminal of the comparator module is electrically connected to the on-voltage, and the other input terminal of the comparator module is configured to receive the adjustment. Voltage, the output terminal is electrically connected to a circuit to be driven, and the comparator module is configured to compare the on-voltage and the adjustment voltage, and then an output terminal of the comparator module outputs a A driving voltage to drive the circuit to be driven; and

A delay module has an input terminal and an output terminal, wherein the input terminal of the delay module is electrically connected to the output terminal of the linear regulator, and the comparator module is configured to receive the output of the output terminal of the delay module. An activation signal;

When the stable voltage received by the input of the delay module is less than a set voltage, the activation signal is a low level, so that the voltage comparator in the comparator module is turned off. The stable voltage received at the input terminal is equal to or greater than the set voltage, and the activation signal is at a high level, so that the voltage comparator is turned on.
The driving circuit according to claim 11, wherein the comparator module has the voltage comparator, a first resistor and a second resistor, and two ends of the second resistor are electrically connected to the respective terminals. The on-voltage and a first terminal of the voltage comparator, and two terminals of the first resistor are electrically connected to the first terminal of the voltage comparator and ground, respectively, wherein the first terminal of the voltage comparator Configured to receive a divided voltage from an input terminal of the comparator module, a second terminal of the voltage comparator is the other input terminal of the comparator module, and an output terminal of the voltage comparator is the Comparator output.
The driving circuit according to claim 12, wherein a first terminal of the voltage comparator is a non-inverting output terminal, a second terminal of the voltage comparator is an inverting input terminal, and the voltage comparison The output terminal of the device is connected to the under-voltage lockout module of the circuit to be driven.
The driving circuit according to claim 12, wherein a ratio of a resistance value of the first resistor to a resistance value of the second resistor is 1:29.
The driving circuit according to claim 12, wherein when a voltage at a first terminal of the voltage comparator is greater than a voltage at a second terminal of the voltage comparator, and the on-voltage is greater than 16V, so The output terminal of the voltage comparator outputs a high level.
The driving circuit according to claim 12, wherein the amplifier module has an operational amplifier, a third resistor, a fourth resistor, and a fifth resistor, wherein a first end of the operational amplifier is The input terminal of the amplifier module, two terminals of the fifth resistor are electrically connected to a second terminal and an output terminal of the operational amplifier, respectively, and two terminals of the fourth resistor are electrically connected to the operational amplifier, respectively. A second terminal and the third resistor, and two terminals of the third resistor are electrically connected to the second terminal of the voltage comparator and ground, respectively.
The driving circuit according to claim 16, wherein a ratio of a resistance value of the third resistor to a resistance value of the fourth resistor is 1: 5.
The driving circuit according to claim 16, wherein a first terminal of the operational amplifier is a non-inverting output terminal, and a second terminal of the operational amplifier is an inverting input terminal.
The driving circuit according to claim 11, wherein the set voltage is 0.5V.
The driving circuit of claim 11, wherein the on-voltage is a gate high voltage output by a level shifter under the control of a timing controller.