CN114882818A - Controller of liquid crystal display - Google Patents

Abstract

The present invention provides a controller of a liquid crystal display capable of reducing power consumption and improving an average operating efficiency of the controller, the controller including: the device comprises a frequency divider, a booster circuit module, a voltage selector, a bias voltage generator, a buffer and a selector matrix; the frequency divider is connected to the clock source and is used for dividing the frequency of the clock source and outputting a frequency-divided clock signal; the booster circuit module outputs a boosted voltage, a phase clock generation module in the booster circuit module converts the frequency-divided clock signal into four paths of clock signals with fixed phase difference, and a voltage selector outputs a target voltage; a bias voltage generator for outputting a set of bias voltages using a target voltage; the buffer is used for buffering the group of bias voltages to obtain a group of buffer voltages; and a selector matrix for selecting a set of buffer voltages outputted from the buffer by digital control to select a target buffer voltage and outputting the target buffer voltage to the liquid crystal display.

Description

A controller for a liquid crystal display

technical field

The invention relates to the field of display driving, in particular to a controller of a liquid crystal display.

Background technique

At present, as a display of a portable electronic device, a segment code type liquid crystal panel is generally used, and a plurality of display pixels are arranged in a matrix in the segment code type liquid crystal panel. In this portable electronic device, a controller for controlling the segment type liquid crystal panel is also installed. The controller is used to drive the driver circuit of the segment code LCD panel. With the continuous improvement of the integration level of integrated circuits, the charge pump circuit is increasingly integrated in the controller of the liquid crystal display, but the average efficiency of the current controller is low, which is not enough to meet the current work requirements.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a controller of a liquid crystal display for reducing power consumption and improving the average working efficiency of the controller.

In a first aspect, the present invention provides a controller for a liquid crystal display, the controller comprising: a frequency divider, a boost circuit module, a voltage selector, a bias generator, a buffer and a selector matrix; the frequency divider The frequency divider is used to divide the frequency of the clock source and output the frequency-divided clock signal; the booster circuit module inputs the power supply voltage VIN and the frequency-divided clock signal , output the boost voltage V5, the phase clock generation module in the boost circuit module converts the frequency-divided clock signal into four clock signals with fixed phase difference, and the four clock signals with fixed phase difference are used for For the timing control of the switching elements in the boost circuit module, so as to control the charge and discharge of the four external capacitors of the boost circuit module; for the voltage selector, the input voltage is the boost voltage V5, Any one of the external power supply voltage VBAT or the internal power supply voltage VBAT, outputs the target voltage VLCD; the bias voltage generator inputs the target voltage VLCD for outputting a set of bias voltages by using the target voltage VLCD; the buffer the selector, inputting a set of bias voltages output by the bias generator, for buffering the set of bias voltages to obtain a set of buffer voltages; the selector matrix, inputting the set of buffer voltages and The target voltage VLCD is used for selecting a target buffer voltage from a group of buffer voltages output from the buffer through digital control, and outputting the target buffer voltage to the liquid crystal display screen.

The beneficial effect of the controller of the liquid crystal display provided by the present invention is that the input voltage of the voltage selector is any one of the boost voltage V5, the external power supply voltage VBAT or the internal power supply voltage VBAT, so that the external power supply voltage VBAT or The internal power supply voltage VBAT can replace the boost circuit module, which can reduce power consumption; in addition, the bias generator can provide a set of bias voltages, so it supports multiple biases, which can effectively control power consumption and improve the average working efficiency of the controller .

Optionally, the selector matrix inputting the set of buffer voltages is replaced by inputting an external supply voltage. The selector matrix can be digitally controlled to select different buffer voltages, thereby enabling LCD blinking and updating the displayed image of the LCD display.

Optionally, the output end of the voltage selector is also connected with an external capacitor, and the external capacitor is used to stabilize the target voltage VLCD, and this structure helps to improve the output voltage stability of the boost module, Improve the average working efficiency of the charge pump.

Optionally, the four-way clock signals include: a first clock signal, a second clock signal, a third clock signal, and a fourth clock signal; the first clock signal and the second clock signal have opposite phases, and the third clock signal and the The four clock signals have opposite phases, the first clock signal and the third clock signal have the same phase, and the second clock signal and the fourth clock signal have the same phase.

Optionally, the bias generator is a low power consumption resistor string, and the set of bias voltages includes a target voltage VLCD, a VLCD/2 bias voltage, a VLCD/3 bias voltage and a VLCD/4 bias voltage.

Optionally, the switching element is constructed of a high-voltage MOS transistor, and the bias generator and the buffer are both low-power consumption devices.

Optionally, the boost circuit module is a linear charge pump.

Optionally, the linear charge pump supports multiple adjustable magnifications.

In a second aspect, the present invention provides an integrated circuit chip including the controller described in any one of the first aspect above. For the beneficial effects, reference can be made to the description of the first aspect above.

In a third aspect, the present invention provides a communication device, and the communication terminal includes the integrated circuit chip described in the second aspect. For the beneficial effects, reference can be made to the description of the first aspect above.

Description of drawings

1 is a schematic diagram of a controller of a liquid crystal display provided by an embodiment of the present invention;

FIG. 2 is a schematic diagram of a group of clock signals provided by an embodiment of the present invention.

Detailed ways

In order to make the purpose, technical solutions and advantages of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings of the present invention. Obviously, the described embodiments are a part of the present invention. examples, but not all examples. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention. Unless otherwise defined, technical or scientific terms used herein should have the ordinary meaning as understood by one of ordinary skill in the art to which this invention belongs. As used herein, "comprising" and similar words mean that the elements or things appearing before the word encompass the elements or things recited after the word and their equivalents, but do not exclude other elements or things.

In view of the problems existing in the prior art, an embodiment of the present invention provides a controller of a liquid crystal display. Voltage selector 30 , bias generator 40 , buffer 50 and selector matrix 60 .

The frequency divider 10 is connected to a clock source, and the frequency divider 10 is used for dividing the frequency of the clock source and outputting the frequency-divided clock signal. Illustratively, the clock source may be an RC oscillator clock source, such as RC32K, or the clock source may be a crystal oscillator clock source, such as XTAL32K. For example, the frequency of the clock source is 32K, and the frequency of the clock signal divided by the frequency divider is 16K, or 8K, or 4K, 2K, and so on.

The boosting circuit module 20 inputs the power supply voltage VIN and the frequency-divided clock signal, and outputs a boosting voltage V5. In this embodiment, the boost circuit module 20 may be a linear charge pump (LCP), and the linear charge pump supports multiple adjustable magnifications, such as 3 times, 4 times, or 5 times. The linear charge pump may include a plurality of switching elements and capacitors, and the switching elements are constructed of high-voltage MOS transistors.

In addition, the linear charge pump further includes a phase clock generation module, the phase clock generation module includes an inverter, and the phase clock generation module is used for converting the frequency-divided clock signal into a four-way clock signal with a fixed phase difference. The four-way clock signals with fixed phase differences are used to perform timing control on the switching elements in the boost circuit module, so as to perform charge and discharge control on the four external capacitors (C1, C2, C3 and C4) of the linear charge pump. .

For example, the four external capacitors in FIG. 1 are C1 , C2 , C3 and C4 respectively. For example, when the frequency of the clock signal is 32K, the size of the capacitors may be 100nf to 500nf. The four-way clock signals with fixed phase differences include a first clock signal CLK 1 <0>, a second clock signal CLK 2 <0>, a third clock signal CLK 1 <1>, and a fourth clock signal CLK 2 <1>, The phase difference can be 45 degrees, 60 degrees, 90 degrees, 120 degrees or 180 degrees, etc. respectively. Exemplarily, when the phase difference is 180 degrees, the four clock signals may be as shown in FIG. 2 , the first clock signal and the second clock signal have opposite phases, the third clock signal and the fourth clock signal have opposite phases, and the first clock signal and the fourth clock signal have opposite phases. The phase of the signal and the third clock signal are the same, and the phase of the second clock signal and the fourth clock signal are the same.

In the voltage selector 30, the input voltage is the boost voltage V5, and the output target voltage VLCD. That is, the booster circuit module 20 supplies the output voltage of the booster circuit module 20 to the voltage selector 30 . Alternatively, the input terminal of the voltage selector 30 can use the external power supply voltage VBAT or the internal power supply voltage VBAT to replace the boost voltage V5. In this way, in order to save power consumption, the charge pump can stop working and use the external power supply voltage VBAT. Or the internal supply voltage VBAT instead of the boost voltage V5. The output end of the voltage selector 30 is also connected to an external capacitor C5, and the external capacitor C5 is used to stabilize the target voltage VLCD.

The bias voltage generator 40 inputs the target voltage VLCD, and is used for outputting a set of bias voltages using the target voltage VLCD. The target voltage VLCD is the highest voltage output by the booster circuit module 20 corresponding to the LCD segment, and the bias voltage generator may be a low-power device or an ultra-low-power device.

As shown in FIG. 1 , the bias generator 40 may be a low-power resistor string, and the set of bias voltages includes a target voltage VLCD, a VLCD/2 bias voltage, a VLCD/3 bias voltage, and a VLCD/4 bias voltage Voltage. Illustratively, a set of bias voltages may include 0V (ground potential), +1V, +2V, and +3V. It should be noted that this embodiment does not limit the voltage quantity and voltage size of a set of bias voltages.

The buffer 50 is inputted with a set of bias voltages output by the bias voltage generator 40, and is used for buffering the set of bias voltages to obtain a set of buffer voltages. The buffer 50 may be an ultra-low power consumption buffer, which mainly buffers the voltage output by the buffer 50 . The buffer 50 can be a resistor string to form a resistive voltage divider, and the buffer 50 can be a low-power device or an ultra-low-power device.

The selector matrix 60 inputs the set of buffer voltages and the target voltage VLCD for selecting a set of buffer voltages output from the buffers through digital control to select a target buffer voltage, and outputs the target buffer voltage to the LCD screen. The LCD screen may be a segment code LCD screen, such as the LCD screen of a water meter or an electric meter.

The chip including the controller of the liquid crystal display can be applied to various communication terminals as an important part of the analog integrated circuit. The communication terminal mentioned here refers to the communication system that can be used in a mobile environment, supports long term evolution (LTE) system, worldwide interoperability for microwave access (WiMAX) communication system, 5th Generation (5th Generation, 5G) systems, such as new radio access technology (NR), and future communication systems, such as 6th generation (6th Generation, 6G) systems and other electronic equipment with various communication standards, including the Internet of Things Devices, Mobile Phones, Laptops, Tablets, Car Computers, etc.

Compared with the prior art, the controller of the liquid crystal display provided by the present invention can output a boost power supply with an adjustable rate by changing the frequency of the clock signal output by the phase clock generating module in the charge pump, and controlling the charging and discharging time of the middle capacitor. , the input voltage of the voltage selector is any one of the boost voltage V5, the external power supply voltage VBAT or the internal power supply voltage VBAT, so that the external power supply voltage VBAT or the internal power supply voltage VBAT can replace the boost circuit module, which can realize Reduce power consumption; in addition, the bias generator can provide a set of bias voltages, so it supports multiple biases, which can effectively control power consumption and improve the average working efficiency of the controller.

The LCD controller is based on a collection of traditional LCD controller functions and performances in the industry, and has the following advantages:

(1) A waveform or B waveform can be selected.

(2) Supports 8 time slices and 4 bias voltages.

(3) Automatic output of segment signals and common signals can be performed by automatically reading the display data register.

(4) The time interval between frames can be changed.

(5) LCD flashing can be performed.

(6) The display image can be updated.

(7) Can support internal VBAT, internal charge pump or external VBAT power supply

(8) Can support internal resistor divider, external resistor divider or external capacitor divider

(9) The internal charge pump can support the output VLCD of the LCD driver after multiplying the input voltage by 3 times, 4 times or 5 times

The circuit, chip and communication terminal of the controller provided by the present invention have been described in detail above. Although the embodiments of the present invention have been described in detail above, it will be apparent to those skilled in the art that various modifications and changes can be made to these embodiments. However, it should be understood that such modifications and changes are within the scope and spirit of the invention as set forth in the appended claims. Furthermore, the invention described herein is capable of other embodiments and of being practiced or carried out in various ways.

Claims (10)

1. a controller of liquid crystal display, is characterized in that, comprises: frequency divider, boost circuit module, voltage selector, bias generator, buffer and selector matrix; The frequency divider is connected to a clock source, and the frequency divider is used to divide the frequency of the clock source and output the divided clock signal; The boost circuit module inputs the power supply voltage VIN and the frequency-divided clock signal, and outputs a boost voltage V5. The phase clock generation module in the boost circuit module converts the frequency-divided clock signal into Four-way clock signals with fixed phase differences, the four-way clock signals with fixed phase differences are used to perform timing control on the switching elements in the booster circuit module, so as to perform sequential control on the four external capacitors of the booster circuit module. charge and discharge control; the voltage selector, the input voltage is any one of the boost voltage V5, the external power supply voltage VBAT or the internal power supply voltage VBAT, and the output target voltage VLCD; The bias voltage generator, inputting the target voltage VLCD, is used for outputting a set of bias voltages by using the target voltage VLCD; the buffer, inputting a set of bias voltages output by the bias generator, for buffering the set of bias voltages to obtain a set of buffer voltages; the selector matrix, inputting the set of buffer voltages and the target voltage VLCD, for selecting a set of buffer voltages output from the buffers through digital control to select a target buffer voltage, and outputting the target buffer voltage to the LCD screen. 2. The controller of claim 1, wherein the selector matrix inputting the set of buffer voltages is replaced with inputting an external supply voltage. 3 . The controller according to claim 1 , wherein the output end of the voltage selector is further connected with an external capacitor, and the external capacitor is used to stabilize the target voltage VLCD. 4 . 4. The controller according to claim 1, wherein the four-way clock signal comprises: a first clock signal, a second clock signal, a third clock signal and a fourth clock signal; The first clock signal and the second clock signal have opposite phases, the third clock signal and the fourth clock signal have opposite phases, the first clock signal and the third clock signal have the same phase, and the second clock signal and the fourth clock signal have the same phase. 5. The controller according to claim 1, wherein the bias generator is a low power consumption resistor string, and the set of bias voltages comprises target voltage VLCD, VLCD/2 bias voltage, VLCD/ 3 bias voltage and VLCD/4 bias voltage. 6 . The controller according to claim 5 , wherein the switching element is constructed of a high-voltage MOS transistor, and the bias generator and the buffer are both low-power consumption devices. 7 . 7. The controller of claim 1, wherein the boost circuit module is a linear charge pump. 8. The controller of claim 7, wherein the linear charge pump supports a plurality of adjustable magnifications. 9 . An integrated circuit chip, characterized by comprising the controller according to any one of claims 1 to 8 . 10 . 10. A communication terminal, comprising the integrated circuit chip of claim 9.

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