BASE BIAS CIRCUIT AND POWER AMPLIFIER USING THE BASE BIAS CIRCUIT

PROBLEM TO BE SOLVED: To provide a base bias supply, circuit for power bipolar transistor(TR) small in chip area, small in consumed current and capable of unnecessitating a choke inductor between a base of the power TR and the bias supply circuit, and to provide an amplifier circuit using the base bias supply circuit. SOLUTION: The base bias circuit 1 acts nearly like a constant voltage source, is configured such that its generating base bias voltage is not susceptible to the effect of a power supply voltage and an ambient temperature, and has a function of controlling the base bias voltage in response to an external control signal. Properly selecting the resistance of resistors 6, 14 downsizes each bipolar TR being a component of the bias circuit 1 to reduce a current consumed by the bias circuit 1 and to eliminate the need for an RF choke inductor between the power TR 13 and the bias circuit 1. That is, the chip is downsized and number of externally mounted components is decreased to reduce the cost.