| 摘要 |
PURPOSE:To eliminate losses for synthesizing a bias voltage and a pulse voltage, by constituting a pulse voltage generating circuit and a bias voltage generating citcuit with one circuit. CONSTITUTION:When a bias voltage controlling signal PB is inputted, a power supply voltage VBH is divided at a dividing tatio controlling citcuit 73 and a bias voltage VBB is generated. At the period when the bias voltage controlling signal PB is inputted, if a pulse voltage controlling signal PH is inputted, the pulse voltage VBH is generated at a dividing ratio controlling circuit 74. In this case, since the power supply voltage is VBH, the voltage dividing ratio is set to 1. Thus, since a superimposing voltage between the bias and pulse voltages is outputted from an output terminal 77 of a pulse voltage generating circuit 70, the losses for synthesizing these two voltages can be eliminated. |
