| 摘要 |
<p>PURPOSE:To shorten off-time by releasing the state of overdrive by a method wherein the current flowing into the light emitting diode of one photo coupler is reduced by using two photo couplers. CONSTITUTION:The photo coupler 1 consists of a light emitting diode 2 and a photo receiving transistor (Tr) 3. The photo coupler 11 consists of a light emitting diode 12 and a photo receiving Tr13. The collector of the Tr3 is connected to the diode 12. When a high level is given to an input signal, a current flows into the diode 2 through resistor r1 and r2, resulting in light emission, and accordingly the Tr3 turns on. Then, the current flows into the diode 12, resulting it light emission, and accordingly the Tr13 turns on. Since the current flows through the resistors r1 and r3, the current of the diode 2 is partially shunted and then reduced.</p> |
