CN101673516B - Liquid crystal screen contrast adjustment circuit for monitoring equipment - Google Patents

Abstract

Translated fromChinese

一种用于监控设备的液晶屏对比度调节电路，涉及液晶显示技术领域，所解决的是现有监控设备的液晶屏对比度调节不便的技术问题。该电路包括显示驱动模块，其特征在于，还包括：按键扫描回路，用于输入对比度调节值；按键驱动模块，其输入端连接按键扫描回路；数据锁存模块，用于产生可调基准电压，其使能端一直有效，控制端接系统控制信号，输入端连接按键驱动模块的数据输出端，输出端连接一排阻，排阻的公共端串接电阻后接地；三极管，其基极连接排阻的公共端，发射极串联一上拉电阻，集电极接显示驱动模块的显示屏对比度调节端，并通过电阻连接显示驱动模块的显示屏电压输出端。本发明提供的电路，调节时不会影响设备正常运行。

A liquid crystal screen contrast adjustment circuit for monitoring equipment relates to the technical field of liquid crystal display and solves the technical problem that the contrast adjustment of the liquid crystal screen of the existing monitoring equipment is inconvenient. The circuit includes a display driver module, which is characterized in that it also includes: a key scanning circuit for inputting a contrast adjustment value; a key driving module, whose input terminal is connected to the key scanning circuit; a data latch module, which is used for generating an adjustable reference voltage, Its enable terminal is always effective, the control terminal is connected to the system control signal, the input terminal is connected to the data output terminal of the key driver module, the output terminal is connected to a resistor, and the common terminal of the resistor is connected in series with a resistor and grounded; the base of the triode is connected to the row The emitter is connected in series with a pull-up resistor, the collector is connected to the display screen contrast adjustment terminal of the display driver module, and connected to the display screen voltage output terminal of the display driver module through a resistor. The circuit provided by the invention will not affect the normal operation of the equipment during adjustment.

Description

A kind of liquid crystal display contrast adjustment circuit that is used for watch-dog

Technical field

The present invention relates to lcd technology, particularly relate to a kind of technology that is used for the liquid crystal display contrast adjustment circuit of watch-dog.

Background technology

In electric system; The human-computer interface system of various watch-dogs provides easy close friend's inquiry service function to the user; The user only need can get into menu through keyboard operation and inquire about various semaphores or control its operation, and through liquid crystal display its operating process and operating result is fed back to the user.Traditional watch-dog all adopts the manual adjustment potentiometer to regulate the contrast of liquid crystal display when producing, and makes it reach the best image state, regulates efficient and quality and under the situation of equipment volume production, be difficult to improve it; And various use occasion environment are different; Equipment is difficult to the contrast of its liquid crystal display of assurance and can drift about in operational process; This moment be if will need open cabinet to its adjusting, and needs the professional to regulate, and regulates extremely inconvenience; Careless slightly meeting has a strong impact on the normal operation of equipment, and production brings serious hidden danger to enterprise security.

Summary of the invention

To the defective that exists in the above-mentioned prior art; Technical matters to be solved by this invention provides a kind of contrast that can use the button on the watch-dog to regulate liquid crystal display; And also can not influence equipment when regulating and normally move, regulate liquid crystal display contrast adjustment circuit very easily.

In order to solve the problems of the technologies described above, a kind of liquid crystal display contrast adjustment circuit that is used for watch-dog provided by the present invention comprises driver module, it is characterized in that, also comprises:

The key scan loop is used to import the contrast adjustment value;

The button driver module, its input end connects the key scan loop;

The data latching module is used to produce adjustable reference voltage, its Enable Pin continuously effective, and control end welding system control signal, input end connects the data output end of button driver module, and output terminal connects an exclusion, ground connection behind the common port series resistor of exclusion;

Triode, its base stage connects the common port of exclusion, the emitter pull-up resistor of connecting, collector connects the display screen contrast adjustment end of driver module, and connects the screen voltage output terminal of driver module through resistance.

Further, said data latching module is for producing the data latching module of 9 grades of adjustable reference voltages.

Further, the display screen contrast adjustment end of said driver module parallel connection one decoupling capacitance carries out filtering.

The liquid crystal display contrast adjustment circuit that is used for watch-dog provided by the invention; Can regulate the contrast of liquid crystal display through button,, also need not the professional and regulate so when regulating, need not to open cabinet; And also can not influence equipment when regulating and normally move, it is very convenient to regulate.

Description of drawings

Fig. 1 is driver module and the circuit diagram of data latching module of the liquid crystal display contrast adjustment circuit that is used for watch-dog of the embodiment of the invention;

Fig. 2 is key scan loop and the circuit diagram of button driver module of the liquid crystal display contrast adjustment circuit that is used for watch-dog of the embodiment of the invention.

Embodiment

Below in conjunction with description of drawings embodiments of the invention are described in further detail, but present embodiment is not limited to the present invention, every employing analog structure of the present invention and similar variation thereof all should be listed protection scope of the present invention in.

Like Fig. 1-shown in Figure 2, a kind of liquid crystal display contrast adjustment circuit that is used for watch-dog that the embodiment of the invention provided comprises driver module P3, it is characterized in that, also comprises:

The key scan loop comprises button K1-K8, is used to import the contrast adjustment value;

Button driver module U1, its input end A0-A7 (2 pin-9 pin) connects the key scan loop through exclusion RP1;

Data latching module U7; Be used to produce adjustable reference voltage; Its Enable Pin OC continuously effective (1 pin ground connection), control end C (11 pin) welding system control signal CS7 (being used to latch control),input end 1D-8D (2 pin-9 pin) connects the data output end B0-B7 (11 pin-18 pin) of load module U1;Output terminal 1Q-8Q (12 pin-19 pin) connects an exclusion RP5, ground connection behind the common port series resistor R6 of exclusion RP5;

One triode Q1; Its base stage connects the common port of exclusion RP5; The emitter pull-up resistor R7 that connects, collector meets the display screen contrast adjustment end V0 (3 pin) of driver module P3, and connects the screen voltage output terminal VOUT (20 pin) of driver module P3 throughresistance R 8.

The adjustable reference voltage that said data latching module U7 is produced has 9 grades, shows that the voltage on the triode Q1 base stage is 9 volts of 5 * (8-x) ÷, wherein x=0,1,2...8.

The display screen contrast adjustment end V0 parallel connection one decoupling capacitance C5 of said driver module P3 carries out filtering.

When regulating lcd contrast; Constantly change the benchmark digital signal (increasing or decreasing) of input through button K1-K8; Digital signal is sent to data latching module U7 after button driver module U1 handles; Data latching module U7 produces reference voltage according to the data that sent, and through changing the emitter junction voltage of triode Q1 with its pin and the exclusion RP5 that connects and theresistance R 6 that is connected in series, it acts on triode Q1 and goes up the back and produce output current; Through afterresistance R 8 dividing potential drops, end reaction is on the display screen contrast adjustment end V0 of driver module P3 again.

When transferring to optimum contrast, the input that stops key, this moment, this group benchmark digital signal promptly was stored in the system, and when switching on next time, this reference signal is directly transferred from system, makes the contrast of adjusting can not be changed.

According to the different pieces of information that button K1-K8 is imported, the exportable 9 grades of reference voltages of data latching module U7, the liquid crystal optimum contrast should be in the position, middle of 9 grades of adjustable voltages when doing material certainly.

Claims (3)

1. a liquid crystal display contrast adjustment circuit that is used for watch-dog comprises driver module, it is characterized in that, also comprises:

The key scan loop is used to import the contrast adjustment value;

The button driver module, its input end connects the key scan loop;

The data latching module is used to produce adjustable reference voltage, its Enable Pin continuously effective, and control end welding system control signal, input end connects the data output end of button driver module, and output terminal connects an exclusion, ground connection behind the common port series resistor of exclusion;

Triode, its base stage connects the common port of exclusion, the emitter pull-up resistor of connecting, collector connects the display screen contrast adjustment end of driver module, and connects the screen voltage output terminal of driver module through resistance.

2. the liquid crystal display contrast adjustment circuit that is used for watch-dog according to claim 1 is characterized in that: said data latching module is for producing the data latching module of 9 grades of adjustable reference voltages.

3. the liquid crystal display contrast adjustment circuit that is used for watch-dog according to claim 1 is characterized in that: display screen contrast adjustment end parallel connection one decoupling capacitance of said driver module carries out filtering.

Images