| 摘要 |
PURPOSE:To improve a high frequency characteristic and stability by making a constant current source take share of the fixed current component of a load current and therefore reducing the current capacity of an output transistor, etc. CONSTITUTION:A constant voltage power supply device consists of a differential amplifier 10, a drive amplifier 30 containing MOSFET 31 and 32, an output FET 33 and a constant current source FET 34 and supplies a load current IL to a load 24. Then the fixed current component IK equal to 1/2 maximum current IL having variable level is supplied to a load 25 through the FET 34 in the form of a constant current source. While the rest amount of current component is supplied to the load 25 from the FET 33 as the variable current component IV. Thus the input electrostatic capacities 35 and 36 of the amplifier 30 and the FET 33 are reduced down to half respectively. Thus both the high frequency characteristics and stability can be improved while maintaining the same current supply capacity as conventional. |
