Patent ID: 6759906
Filing Date: 2004-07-06
Classification: H03F,H03G

Abstract:
A high frequency power amplifier circuit device having multiple output stages, each including a plurality of first semiconductor amplification elements connected in a cascade and a bias control circuit that drives each of said plurality of first semiconductor amplification elements according to an inputted control voltage,wherein said bias control circuit applies an initial bias voltage to the control terminal of each of said plurality of first semiconductor amplification elements, thereby supplying a current to said semiconductor amplification element even when said input control voltage is practically â€œ0â€ , wherein said initial bias voltage applied to each of said plurality of first semiconductor amplifier elements is controlled so as to become higher gradually from the first stage to the last stage, and wherein the change rate of said bias voltage applied to said control terminal of each of said plurality of first semiconductor amplification elements is controlled so as to become lower gradually from the first stage to the last stage until the first voltage becomes higher than the threshold voltage of said semiconductor amplification elements and higher gradually from the first stage to the last stage when said first voltage is exceeded.