| 摘要 |
PROBLEM TO BE SOLVED: To provide a feedback circuit whose circuit stability is not impaired even during low-voltage output, and a series regulator using it. SOLUTION: The series regulator is provided with an error amplifier 11 in which a non-inverting input terminal 11b is connected to a reference voltage generation circuit; a voltage dividing circuit 13 for dividing an output voltage Vo of the error amplifier 11; and a phase compensation circuit 14 having a non-inverting amplifier 15 in which an input terminal 15a is connected to a voltage dividing point of the voltage dividing circuit 13, a first impedance generation means 16 connected between an output terminal 15c of the non-inverting amplifier 15 and an inverting input terminal 11a of the error amplifier 11, and a second impedance generation means 17 connected between the voltage dividing point of the voltage dividing circuit 13 and the inverting input terminal 11a of the error amplifier 11. Even if voltage amplification degree Av1 of the non-inverting amplifier 15 is larger than one, and a feedback amount is one, a zero frequency fz of the phase compensation circuit 14 is smaller than a pole frequency fp. COPYRIGHT: (C)2009,JPO&INPIT
|
