| 摘要 |
PURPOSE:To obtain a switcher control circuit which uses the control line and the tally line, by providing the reverse-current protective diodes on the input side of the latch circuit, and also providing the voltage shifting elements in the output side of the tally driving circuit. CONSTITUTION:The reverse-current protective diodes D1-Di are inserted into the input side of the latch circuit 2, Zener diodes Z1-Zi are inserted as voltage shifting elements into the output side of the tally driving circuit 3, and the control line and the tally line are used in common. And the bias voltage VD is applied to the input side of the latch circuit 2, but since it is grounded through the diodes D1-Di when the control buttons B1-Bi have been pushed, the input side of the latch circuit becomes ''low'', and its input is latched. Subsequently, a tally signal is returned from the tally driving circuit 3, and the tally lamp is turned on through the diodes Z1-Zi. In this case, an input of the latch input side is made to become ''high''. |
