| 摘要 |
PURPOSE:To attain further miniaturization and economy, by replacing a bootstrap circuit including capacitors into other circuit constitution easy for circuit integration so as to obtain a power. CONSTITUTION:The constitution of a power circuit is taken as that collectors of a PNP transistor (TR) and an NPN TR are connected and an output is extracted from the connecting point. Thus, the power P is expressed in equation written at the right side, where VCEsat is a collector-emitter voltage at the saturation of the TRQ5 or Q6, and RL is a load resistor. The VCEsat depends on the construction of the TRs, and in the power transistors, this value is set so as to be sufficiently low. Thus, the bootstrap circuit including capacitors provided for obtaining power is not required, resulting that the reduction in externally mounted capacitors and terminals for circuit integration is attained. That is, an output amplifying circuit possible for further miniaturization and economy is obtained in comparison with conventional circuits in case of the circuit integration. |
