| 摘要 |
PURPOSE:To exactly obtain a necessary characteristic by means of a simple constitution, by providing outputs of an output voltage detecting circuit and an output current circuit to separate error amplifiers, respectively, and controlling them. CONSTITUTION:An external control signal provided to a terminal T4 is supplied as reference voltage through a control element 17 to an input side positive terminal of an error amplifier 16. An output of an output current detecting circuit 15 is supplied to an input side negative terminal of the amplifier 16, therefore, its output is varied in proportion to voltage of the input side positive terminal. This output signal is negative-fed back to a controlling circuit 11, and since control by this signal is executed, a stable output is supplied to a load in accordance with the external control signal. Output voltage is fed back to the input side negative terminal of an error amplifier 20 by an output voltage detecting circuit 14. To the input side positive terminal of the amplifier 20 is supplied reference voltage 21, its output is supplied to a control terminal of the element 17, and as a result, the external control signal is controlled in series. In this regard, in case when this device is constituted so as to have a constant-voltage characteristic, outputs of the circuits 14, 15 are supplied so as to be a reverse relation. |
