JPH04288884A - Led drive semiconductor device for optical communication - Google Patents

Abstract

PURPOSE:To prevent an LED drive current from flowing and achieve a low power consumption when no data signal is input by detecting presence or absence of data signal and then turning on a constant-voltage source at the LED drive portion only when there is data signal. CONSTITUTION:When a data signal is input from a data input terminal 4, input of data is detected by a data signal detection portion 6 and an LED drive portion 2 is switched by a switch 7 so that LED drive current flows constantly. Also the data signal is input to the LED drive portion 2 and one terminal drives an LED 1 of a power supply 5 and then transmits the data signal. On the other hand, when no data signal is input from the data input terminal 4, it is detected that no data is input by the data signal detection portion 6 and the LED drive portion 2 is switched so that no LED drive current flows to the constant power supply source 3 by the switch 7.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an LED driving semiconductor device for optical communication that drives an LED of an optical transmitter.

0002

2 is a block diagram of a conventional LED driving semiconductor device for optical communication. In the figure, 1 is an LED, 2 is an LED driving section that drives the LED 1, and 3 is a constant voltage that determines the current that drives the LED 1. 4 is a data signal input terminal, and 5 is a power source.

Next, the operation will be explained. A data signal is input to the LED drive unit 2 from the data input terminal 4, and the LED
One terminal of the drive section 2 causes a current to flow through the LED 1 of the power source 5 to drive it and transmit a data signal. The current for driving the LED 1 is made constant by the time constant voltage source 3.

0004

[Problem to be solved by the invention] Conventional LED for optical communication
Since the driving semiconductor device is configured as described above, there is a problem that even when there is no data signal, a current flows through the LED driving section to drive the LED.

[0005] This invention was made to solve the above-mentioned problems, and it is an LE for optical communication in which the current for driving the LED does not flow through the LED drive section when there is no data signal.
The purpose is to obtain a D-drive semiconductor device.

[0006]

[Means for Solving the Problems] An LED driving semiconductor device for optical communication according to the present invention detects a data signal, operates a constant voltage source when data input is input, and causes a driving current to flow through the LED. It is something.

[0007]

[Operation] In the optical communication LED driving semiconductor device according to the present invention, by detecting that a data signal is input, the constant voltage source operates, and the LED driving current flows only when the data signal is input. Become.

[0008]

[Example] Example 1. An embodiment of the present invention will be described below with reference to the drawings. Figure 1
In, 1 to 5 are the same as 1 to 5 shown in the conventional example of FIG. 2, so the explanation will be omitted. 6 is a data signal detection unit that detects the presence or absence of a data signal; 7 is a constant voltage source 3 that operates so that an LED drive current flows when a data signal is present;
This is a switch that switches the constant voltage source 3 so that no LED drive current flows when there is no data signal.

Next, the operation will be explained. When a data signal is input from the data input terminal 4, the data signal detection unit 6
detects that data has been input, and switches the constant voltage source 3 to LED so that the LED drive current flows constantly by the switch 7.
Switch the D drive section 2. Further, the data signal is input to the LED driving section 2, and one terminal drives the LED 1 of the power source 5 to transmit the data signal.

On the other hand, if no data signal is input from the data input terminal 4, the data signal detector 6 detects that no data is input, and the switch 7 switches the constant voltage source 3 to LE.
Switch the LED drive unit 2 so that the D drive current does not flow.

[0011]

As described above, according to the present invention, the presence or absence of a data signal is detected and the constant voltage source is switched, so that when there is no data signal, the L
This has the effect of not consuming ED driving current.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an LED driving semiconductor device for optical communication according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a conventional LED driving semiconductor device for optical communication.

[Explanation of symbols]

1 LED 2 LED drive section 3 Constant voltage source 4 Data signal input terminal 5 Power supply 6 Data signal detection section 7 Switch

Claims (1)

[Claims] 1. An LED driving semiconductor for optical communication, comprising an LED driving section, a constant voltage source that applies voltage to the driving section, and a data signal detection section that turns on the constant voltage source when a data signal is input. Device.