| 摘要 |
<p>PURPOSE:To accurately control a source voltage supplied to a circuit, equipped with a protection diode supplying a current from an input line to a source voltage supply line, without being affected by a detour current due to the protection diode. CONSTITUTION:An emitter follower power circuit consisting of a Zener diode ZDo and an NPN type transistor TRo is provided with a diode D10, a resistor R10, and a PNP type transistor TR10; and a source voltage VDD is limited to lower than the specific voltage obtained by adding a 1st reference voltage determined by the Zener diode ZDo and diode D10 and the emitter-base voltage of the transistor TR10 when the power supply line L1 is ON or to less than the specific voltage obtained by adding a 2nd reference voltage (0V) obtained by the resistor R10 and the emitter-base voltage of the TR10 when the power supply line L1 is OFF.</p> |
