公开(公告)号：JPH1195847A

公开(公告)日：1999-04-09

申请号：JP19335898

申请日：1998-07-08

Applicant: ST MICROELECTRON INC

Inventor： MAIKERU JIEI KARAHAN JIYUNIA ,  UIRIAMU II EDOWAAZU

IPC: G05F1/56 ,  G05F1/565 ,  G05F1/575 ,  H02J1/00

Abstract: PROBLEM TO BE SOLVED: To increase the stability without increasing power dissipation by making a switched capacitor operate to vary the zero of the voltage regulator as a function of its output current. SOLUTION: An error amplifier 24 compares a reference voltage VREF with a regulated voltage VREG supplied to the error amplifier 24 through a feedback circuit consisting of a resistance 34 and a resistance 36. Resistances 34 and 36 are constituted as a voltage divider for scaling the regulator voltage VREG and feeds the scaled voltage to the inverted input terminal of the error amplifier 24. The integrator consisting of the amplifier 26, the switched capacitor 30, and a capacitor 32 has zero having a frequency represented as fZERO=1/2πC32 Reff (Reff =1/fVCOC30 ), so a pass transistor 28 regulates a voltage source VDD in response to the output of the error amplifier 24 and integrator, and then generates the regulated voltage VREF.