| 摘要 |
PROBLEM TO BE SOLVED: To provide a voltage variable regulator capable of varying a regulator output and having a high ripple removal rate by operating a feedback quantity control means stably. SOLUTION: This regulator comprises a negative feedback amplifier Amp which amplifies the difference between a reference voltage Vref and a feedback quantity Vf, an output transistor PMOS, and a feedback quantity control means FBC which controls an output Vout variably by controlling the feedback quantity Vf through a feedback resistor group (R1, 32R, 16R,... R, R2). The feedback quantity control means FBC comprises switching elements (NM1-NM6) which are connected to feedback resistors (32R, 16R... R) in parallel, gate elements Q1-Q6, a trimming circuit Trim which controls the feedback quantity Vf by feeding Hi, Low signal to the gate elements Q1-Q6, and a noise suppressing means NS which suppresses a noise signal Vtn from the gate elements Q1-Q6 to the switching elements (NM1-NM6). COPYRIGHT: (C)2004,JPO
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