| 摘要 |
PURPOSE:To compensate the dropout simply, by constituting the amplifiers for main signal and compensating signal respectively with amplifiers of emitter grouding type and base grounding type and making equal the resistance value of the emitter resistors and the base voltage of the transistors (TRs) of these amplifiers. CONSTITUTION:At dropout, a voltage at a switching signal input terminal 11 is higher than a voltage at a switching signal input terminal 12, and a collector current of a TRQ2 flows to Vcc through a TRQ6 and resistor R6. Thus, a compensation signal through a 1H delay circuit 8 appears at an output terminal 6 to compensate dropout. In this case, the amplifiers for main and compensation signals are constituted with a common emitter amplifier consisting of a TRQ1 and a common base amplifier consisting of a TRQ2, the base voltage and emitter resistors R3, R4 for the TRs Q1, Q2 are made equal. Thus, the dropout compensating circuit is constitued with only 7 pieces of TRs and resistive elements. |
