A Method of LDO Circuit Layout

Abstract

An LDO circuit layout method, by setting the RC filter circuit at the bottom, and setting the isolated ground wire around the RC filter circuit, the top of the isolated ground wire is an error amplifier, and the input terminal of the error amplifier is connected to the RC filter circuit. The filter circuits are adjacent to each other to prevent the RC filtered signal from being interfered, thereby improving the power supply rejection ratio of the LDO circuit.

Description

technical field [0001] The invention relates to LDO (low dropout regulator, low dropout linear regulator) technology, in particular to an LDO circuit layout method. Above the isolation ground wire is an error amplifier, and the input end of the error amplifier is adjacent to the RC filter circuit, so as to avoid the interference of the RC filtered signal, thereby helping to improve the power supply rejection ratio of the LDO circuit. Background technique [0002] The LDO circuit is a low dropout linear regulator circuit in an integrated circuit, which needs to have a high power supply rejection ratio (PSR) and low noise. The working principle of the LDO circuit is that the bandgap reference BGR generates a reference voltage, which is amplified by the regulator circuit to the desired voltage, and then filtered out by the RC filter circuit to generate a purer voltage. After the error amplifier EA, Buffer BUF and power tube POWER to improve its driving ability and resist exter...

AI Technical Summary

Problems solved by technology

The difficulty of such an LDO circuit layout is that the purer voltage after RC filtering has no driving ability, and is easily disturbed by the internal wiring of the circuit. The weak parasitic capacitance will deteriorate the power supply rejection ratio, resulting in the failure to achieve the desired voltage regulation. Effect

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