| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a power module for a high frequency where an amplification factor of a high frequency signal and an output power (transmission power) are stably controlled without being susceptible to the effect of a high frequency ground pattern on a mount board. SOLUTION: An input stage of the power module is provided with a differential amplifier 11 that receives a balanced high frequency signal and amplifies the signal and also provided with a bias current setting circuit 15 that sets a bias current of the differential amplifier depending on an external gain control signal to set variably a gain of the differential amplifier. Then the amplifier system connects with a virtual ground so that the power module is hardly susceptible to the effect of the high frequency ground pattern and the amplification gain can simply be adjusted stably only with adjustment of the bias current.</p> |
