電力増幅回路

Power amplifier circuit

Abstract

PROBLEM TO BE SOLVED: To provide a power amplifier capable of suppressing heat production by reducing electric power loss. SOLUTION: A power amplifier circuit 30 comprises a voltage amplifying section E, a power amplifying section W including power transistors Q1, Q2 taking low power supply voltage ±V L or high power supply voltage ±V H as power supplies, high speed power switching elements Q3, Q6 for switching the voltage of the power amplifying section W to either of ±V L or ±V H , a reference voltage generator circuit 12 for generating reference voltage ±V SX , and a control circuit 13 for controlling the on/off of the Q3, Q6 based on the comparison of V OUT and V SX . There is further provided power supply switching means 15 for switching the voltage such that the low power supply voltage ±V L is supplied when V OUT is smaller than a predetermined voltage while the high power supply voltage ±V H is supplied when V OUT is larger. Particularly, the reference voltage ±V SX generated from the reference voltage generator circuit 12 is provided by outputs M1, M2 at the connection middle point of the constant voltage element Z of a constant voltage circuit connected between the low power supply voltages +V L and -V L and an operation current setting element U of the same. COPYRIGHT: (C)2005,JPO&NCIPI
【目的】電力ロスを低減して発熱を抑える電力増幅器を提供する。 【構成】電力増幅回路30は、電圧増幅部Eと、低圧電源±V L 又は高圧電源±V H を電源とするパワートランジスタQ1、Q2を備える電力増幅部Wと、電力増幅部Wの電源を±V L 又は±V H の何れかに切り替える高速電力スイッチング素子Q3、Q6と、基準電圧±V SX を生成する基準電圧生成回路12と、V OUT とV SX との比較に基づいてQ3、Q6をオン・オフ制御する制御回路13と、を有し、V OUT が所定電圧よりも小さい場合は低圧電源±V L が供給され、大きい場合は高圧電源±V H が供給されるように切り替える電源切替手段15と、を備えており、特に、基準電圧生成回路12から生成される基準電圧±V SX が、低圧電源+V L と−V L の間に接続された定電圧回路の定電圧素子Zと動作電流設定用素子Uの接続中点の出力M1、M2で与えられる構成。 【選択図】 図1

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    JP-2011061611-AMarch 24, 2011Ricoh Co Ltd, 株式会社リコーOperational amplifier