| 摘要 |
PURPOSE:To reduce harmonic distortion of a high level and to improve the sound quality by connecting a gate of an enhancement MOSFET constituting an output stage to a power supply via a diode so as to prevent the saturation of a transistor (TR) driving the MOSFET. CONSTITUTION:A collector potential of a PNPTR12 is changed in proportion to a signal, the potential is clamped to a voltage of a power supply 22 by a diode 20 to a positive side and not higher than a value subtracting a forward voltage of the diode 20 from the voltage of the power supply 22. A voltage larger than a collector-emitter saturated voltage remains between the collector and emitter of the PNPTR12 so as to prevent the saturation of the PNPTR12. Further, the potential is clamped to a voltage of a power supply 23 by a diode 21 to the negative side, a voltage larger than the collectoremitter saturated voltage remains between the collector and emitter of an NPNTR14 so as to prevent the saturation of the NPNTR14. |
