| 摘要 |
PURPOSE:To reduce the power consumption at the operation time of the control Tr for the driving circuit of capacitive load charge such as the PDP element by inserting the variable resistor of the voltage dependance type into the base circuit of charging transistor Tr. CONSTITUTION:In case capacitive load CL is charged, the high-voltage pulse is applied to terminal Vin and then the zero or negative input signal is applied to the base of control Tr TR1. As a result, TR1 is turned off, the collector potential of TR1 rises up, the voltage across variable resistor Z is reduced, and the value of resistor Z is increased. Accordingly, charging Tr TR2 is turned on the secure effective flow of charging current TE. In the steady state under which the high voltage is applied to terminal Vin, TR1 is turned on to clamp the application voltage. In this case, the voltage applied across resistance Z becomes nearly identical to the high voltage to be applied to Vin, and the value of Z increases greatly. As a result, the current flowing to TR1 is reduced to reduce the power consumption as well as to prevent the breakdown of TR1. |
