| 摘要 |
PURPOSE:To reduce the loss of a transistor by adding the current reference of a load to the current reference of a current minor loop, and by permitting the same current, to flow, as load current, to a chopper circuit. CONSTITUTION:A voltage reference V* and the voltage V of a capacitor 5 detected by a voltage detector 7 are compared with each other to be amplified by an amplifier 9, and its output V9 is compared with current IC detected by a current detector 6 to be amplified by a current controlling amplifier 22, and by PWM-controlling a transistor 2 via a PWM circuit 12, voltage having a current minor loop is controlled. A current I* set by a load current setting device 16 is added to V9 via a leading circuit 24, and input as a load current reference IL* to an amplifier 17 via a delay circuit 23, and is compared with the output of a current detector 15 then to be amplified. Then, load current IL is controlled to coincide with the load current reference IL*. Consequently, the current IC of a chopper circuit and the load current IL coincide with each other, and the voltage drop of a transistor 14 is hardly changed. |
