| 摘要 |
<p>PURPOSE:To diminish the number of parts by providing an external signal detection circuit for detecting an oscillation signal inputted from the outside and a synchronous circuit for stopping the output of an oscillation circuit through said detection signal from the detection circuit and for controlling a booster control signal generation circuit. CONSTITUTION:A booster circuit 2 is composed of an oscillation circuit 21 for self-free run oscillating a signal with a given frequency, an oscillation switching circuit 22, a booster control signal generation circuit 23, a booster transistor circuit 24 having booster capacitors CO, CL and is outputted from the output terminal 25. In this case, there are provided an external signal detection circuit 27 for detecting a signal inputted from an external signal input terminal 26 and a synchronous circuit 28, to switch said oscillation switching circuit 22 by a signal from said synchronous circuit 28, to stop the output to said circuit 23 of a signal from said oscillation circuit 21 and to input the inputted external signal as a synchronizing signal to said generation circuit 23. Thus, a space for taking in capacitors CO, CL is reduced.</p> |
