| 摘要 |
PURPOSE:To realize the transmitting power control circuit of a high output amplifier using such an FET (transistor) as the conversion efficiency of its power source power is not deteriorated, even when output power of its high output amplifier is controlled to a smaller prescribed value than its maximum value, with regard to the transmitting power control circuit for controlling so that the output power of the high output amplifier for mulitstage-amplifying a signal to be modulated of a transmitting part of a portable telephone terminal becomes a prescribed value. CONSTITUTION:In a transmitting power control circuit for controlling so that output power of a high output amplifier 14 for multistage-amplifying a signal to be modulated of a transmitting part of a portable telephone terminal by an element FET becomes a prescribed value, this circuit is provided with a control circuit 1 for setting a drain voltage Vd of the element FET of the high output amplifier 14 to 'O'v and generating a control signal C which can vary a gate voltage Vg to the negative direction, and constituted so that a necessary FET in the mulitstage FET of the high output amplifier 14 controlled by the control signal C of an output of the control circuit 1 is operated as an attenuator having no gain and the output power of the high output amplifier becomes a prescribed value which falls by a prescribed value from the maximum value. |
