Realtek Semiconductor Inc.

Hsueh-Yu Kao

Yi Feng

Yi-Shao Chang

A low-dropout regulator includes an amplifier circuit, a buffer circuit, a control circuit, a power transistor, and a feedback circuit. The amplifier circuit is configured to operate based on an input voltage and generate a first voltage at a first node according to a reference voltage and a feedback voltage. The buffer circuit is configured to generate a second voltage at a second node according to the first voltage. The control circuit is configured to work with the buffer circuit to form a noise canceller. The noise canceller is coupled between the first node, the second node, and a voltage terminal. The power transistor is configured to generate an output voltage according to the input voltage and the second voltage. The feedback circuit is configured to generate the feedback voltage according to the output voltage.

Low-dropout regulator with noise cancellation and operation method thereof

A low dropout regulator includes output terminal circuit and amplifier. The output terminal circuit is configured to generate output voltage according to input voltage and is configured to generate feedback voltage according to the output voltage. The amplifier is configured to generate control voltage to the output terminal circuit according to reference voltage and the feedback voltage, so as to adjust the output voltage, wherein the amplifier includes input stage circuit, current mirror circuit and filter circuit. The input stage circuit is configured to receive the reference voltage and the feedback voltage to generate a differential output. The filter circuit is configured to filter the input voltage to generate dependent current related to noise of the input voltage on the current mirror circuit, wherein the current mirror circuit is configured to output the control voltage according to the differential output and the dependent current.

Low dropout regulator

A low dropout regulator includes an output circuit and an amplifier. The output circuit includes a signal input end configured to receive an input voltage and a signal output end configured to output an output voltage. The amplifier includes a first stage amplifier circuit, a second stage amplifier circuit, a first feedback circuit and a second feedback circuit. The first stage amplifier circuit includes a positive output end and a negative output end. The second stage amplifier circuit includes an input end and an output end, wherein the input end and the positive output end are coupled at a first node, and the output end is coupled to the output circuit. The first feedback circuit is coupled between the negative output end and the output end. The second feedback circuit is coupled between the first node and the output end.

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Hsinchu, Taiwan

Hsueh-Yu Kao