| 摘要 |
PURPOSE:To control directly turn on and turn-off of a light emitting diode by emitter-coupled logic (ECL) outputs, by employing a circuit structure in which output emitter-follower transistors of the ECL are used in common and caused to perform switching operation to turn on or turn off the light emitting diode utilizing both the in-phase and negative-phase outputs thereof. CONSTITUTION:The in-phase and negative-phase outputs of a conventional ECL are respectively connected to terminals OT and OC. And, the OT and OC outputs are connected to the inputs of a light emitting diode and a conventional rectifier diode, respectively, respective of which cathodes are connected in common and the interconnection therebetween is connected to a power source VEE through a resistor R3. Now, when an input VI is of high level, an output VOH of high level is developed across the output OT and the earth so that the light emitting diode LED is turned on. Next, when the input VI is of low level, a bias current, which is corresponding to the current during the light emitting diode LED being turned on, is caused to flow through the rectifier diode D. On the other hand, only current of the order of leakage current is caused to flow through the light emitting diode LED so that the diode LED is turned off and is not lighted. |
