| 摘要 |
PURPOSE:To save the accessory and to protect an electronic circuit from external noise by providing a reset circuit section acting like hysteresis to the amplitude of a power voltage into a single integrated circuit. CONSTITUTION:When a voltage rises and exceeds a diode VD after application of power supply VCC to the integrated circuit, an IIL transistor (Tr) 2 is conducted by a current from a Tr 1 to reset FFs 10, 11. When the voltage rises further to turn on a Tr 3, the Tr 2 is cut off, the reset of the FFs 10, 11 is released and the FFs 10, 11 goes to normal operating state. In this case, Trs 5, 6 are conducted, the Tr 6 enters the saturating state, the collector of the Tr 6 rises up to the power voltage and a voltage across a resistor R3 reaches a voltage being a division of the voltage VCC by resistors R2, R3. Then even when the power voltage drops abnormally due to noise and the VCC is decreased up to (1+R2/R3) times of the base-emitter voltage VBE, the circuit is operated normally.
|
