Patent ID: 11927975
Assignee: PIXART IMAGING INC.
Field: Control (Instruments)
Classification: CPC G | IPC G

Claim 13:
14. A regulator circuit, configured to generate a regulated output signal, the regulator circuit comprising:
a reference circuit, configured to generate a reference signal;
an error amplifier, configured to generate an error amplification signal according to a difference between the reference signal and a feedback signal, wherein the feedback signal is correlated to the regulated output signal; and
an output transistor, which is controlled by the error amplification signal and is configured to convert an input power to generate the regulated output signal;
wherein the reference circuit includes:
a pair of reference devices having a predetermined bandgap;
an amplification circuit, coupled to the pair of reference devices to generate a reference signal according to the bandgap of the pair of reference devices; and
a switch circuit, coupled to the amplification circuit and is configured to control a gain of a feedback network coupled to the amplification circuit, the switch circuit including:
a switch, wherein a PSRR (power supply rejection ratio) of the reference circuit is determined by the switch;
a first driver, configured to drive the switch, wherein the first driver is powered by a supply current; and
a supply transistor, configured to generate the supply current, wherein the supply transistor is biased in a subthreshold region, such that the PSRR of the reference circuit is higher than a predetermined level within a predetermined frequency range.