JP2906847B

• Main Authors: IKUTA HIDEKI, MANBO MITSUHIKO
• Format: Patent
• Language: English
• Published: 21.06.1999
• Edition: 6
• Subjects: AMPLIFIERS; BASIC ELECTRONIC CIRCUITRY; ELECTRICITY

PURPOSE:To provide a circuit suitable for circuit integration by reducing the circuit scale with respect to the high frequency amplifier circuit used for, e.g. a digital portable telephone set. CONSTITUTION:The high frequency amplifier circuit comprising a 1st bias voltage application section 3a in which a collector of a 2nd transistor(TR) whose emitter connects to a constant current source connects to an emitter and a base of a 3rd TR via a resistor and a capacitor and a DC voltage is fed to a collector of a 3rd TR and comprising a 1st bias voltage application section 3a applying a bias voltage to the 1st high frequency amplifier section is provided with a 2nd high frequency amplifier section 2b, a bias voltage application section 3b and a changeover section 4 interrupting the application of a DC voltage in the DC voltages fed to the 1st and 2nd high frequency amplifier sections, emitters of the 3rd TR are directly connected and a high frequency signal is extracted via a DC block capacitor and a reference voltage is applied in common to 1st and 2nd bias voltage application sections.