CN201138879Y

CN201138879Y - LED Control circuit

Info

Publication number: CN201138879Y
Application number: CNU2007201218841U
Authority: CN
Inventors: 王勇; 刘建伟; 董晓勇
Original assignee: Shenzhen H&T Intelligent Control Co Ltd
Current assignee: Shenzhen H&T Intelligent Control Co Ltd
Priority date: 2007-07-31
Filing date: 2007-07-31
Publication date: 2008-10-22
Anticipated expiration: 2017-07-31

Abstract

The utility model relates to an LED control circuit that comprises an LED1 to be controlled and an LED2 to be controlled. The anode of one bypass diode D1 is connected with the anode of the LED1; the cathode of the diode D1 is connected with the cathode of the LED2; the anode of the LED1 is connected with a VDD; the cathode of the LED2 is connected with an earthing end; the cathode of the LED1 and the anode of the LED2 are both connected with one I/O port P1 of a single chip; a resistance R1 is connected between the LED1 and the VDD; and a resistance R2 is connected between the LED2 and the earthing end. The control circuit has a simple structure, and effectively adopts the three different states of the I/O port of the single chip: high level, low level and high resistance state; thus one I/O port can be used for controlling four states of two LED diodes; and the costs of the system design are reduced.

Description

The LED control circuit

Technical field

The utility model relates to a kind of LED control technology, is meant a kind of LED control circuit especially.

Background technology

LED (light-emitting diode) light-emitting diode is a kind of display device that is in daily use in control system, as the indication of each function and beautify outward appearance.

The control regular meeting of LED utilizes microprocessors such as single-chip microcomputer, thus by single-chip microcomputer output high level, low level can control corresponding LED bright entirely, all do not work.In traditional control mode, each LED that the same I/O mouth of single-chip microcomputer is controlled is bright simultaneously or does not work simultaneously that though can make the LED flicker by the level that the output height replaces, the may command state is few, too inflexible, be difficult to the effect that realizes that part is bright, part does not work.

The utility model content

Technical problem to be solved in the utility model is: a kind of LED control circuit is provided, and its circuit is simple, and can control more state, thereby simplified system reduces the system design cost.

For solving the problems of the technologies described above, the utility model adopts following technical scheme: a kind of LED control circuit, comprise LED1 to be controlled, LED2, and the positive pole of a bypass diode D1 connects the anode of LED1, and the negative pole of diode D1 connects the negative electrode of LED2; The anode of LED1 is connected to VDD; The negative electrode of LED2 connects earth terminal, and the anode of the negative electrode of LED1 and LED2 is connected in an I/O mouth P1 of single-chip microcomputer jointly.

Preferably, be connected a resistance R 1 between described LED1 and the described VDD, be connected a resistance R 2 between described LED2 and the earth terminal.

The beneficial effects of the utility model are: this control circuit is simple in structure, and effectively utilized the I/O mouth that has in the single-chip microcomputer can be set to three kinds of different states: high level, low level and high-impedance state, thereby showed control to four kinds of states of two LED with an I/O cause for gossip, that is: LED1 is lighted, and LED2 does not work; LED2 is lighted, and LED1 does not work; LED1 and LED2 all do not work; Alternately light LED1, LED2 with certain frequency, utilize people's visual persistence effect, making human eye perceives LED1 and LED2 all is bright state.Adopt this control circuit can reduce the system design cost.

Below in conjunction with accompanying drawing the utility model is described in further detail.

Description of drawings

Fig. 1 is the utility model LED control circuit schematic diagram.

Embodiment

See also Fig. 1, the utility model provides a kind of LED control circuit, and it can utilize the existing control to two LED of an I/O cause for gossip of single-chip microcomputer/microprocessor.

Its particular circuit configurations is as follows: the LED1 that need control, LED2 connect, and the positive pole of a bypass diode D1 are connect the anode of LED1; The negative pole of diode D1 connects the negative electrode of LED2; The anode of described LED1 is connected to VDD, and also can be connected a resistance R 1 between LED1 and the VDD; The negative electrode of described LED2 connects earth terminal, and also can be connected a resistance R 2 between LED2 and the earth terminal; And the anode of the negative electrode of LED1 and LED2 is connected in an I/O mouth P1 of single-chip microcomputer jointly.Resistance R 1, R2 are as current-limiting resistance, and its concrete parameter can be selected according to circuit and actual the requirement.

When concrete control, can realize four kinds of state of a controls altogether:

1) when I/O mouth P1 was low level, LED1 was lighted, and this moment, the LED2 no current flow through, can be not bright;

2) when I/O mouth P1 was high level, LED2 was lighted, and this moment, the LED1 no current flow through, can be not bright;

3) when I/O mouth P1 is high-impedance state, this moment, LED1 and LED2 were by diode connected in parallel D1 bypass, and LED1, LED2 all can be not bright;

4) when I/O mouth P1 under a certain fixed frequency, when the duty ratio with 50% is carried out not stall of high-low level and changed, then utilize people's visual persistence effect, making human eye perceives LED1 and LED2 all is bright state.

This control circuit is simple in structure, and effectively utilized the I/O mouth that has in the single-chip microcomputer can be set to three kinds of different states: high level, low level and high-impedance state, thereby showed control with an I/O cause for gossip, and can reduce the system design cost four kinds of states of two LED.

Claims

1, a kind of LED control circuit comprises LED1 to be controlled, LED2, it is characterized in that: the positive pole of a bypass diode D1 connects the anode of LED1, and the negative pole of diode D1 connects the negative electrode of LED2; The anode of LED1 is connected to VDD, and the negative electrode of LED2 connects earth terminal, and the anode of the negative electrode of LED1 and LED2 is connected in an I/O mouth P1 of single-chip microcomputer jointly.

2, a kind of LED control circuit as claimed in claim 1 is characterized in that: be connected a resistance R 1 between described LED1 and the described VDD, be connected a resistance R 2 between described LED2 and the earth terminal.