BIAS CURRENT SETTING CIRCUIT OF POWER AMPLIFIER CIRCUIT USING STATIC INDUCTION TRANSISTOR

PROBLEM TO BE SOLVED: To provide a bias circuit suppressing the supply voltage variation dependence of current (idling current) in the absence of signals that flows to the transistor of the final stage of a power amplifier for audio especially using a static induction transistor for the final stage. SOLUTION: In the bias current setting circuit of the power amplifier circuit using the static induction transistor, there are provided: a circuit obtaining a voltage proportional to a supply voltage itself; and a circuit partially taking out a proportional voltage by a variable resistor to decide a current flowing to a bias resistor connected between the gate and source of an output transistor by the voltage, thus giving an idling current in which the influence of supply voltage fluctuations and variations are suppressed. COPYRIGHT: (C)2009,JPO&INPIT