Improved type low-dropout linear regulator

Abstract

The invention discloses an improved low-dropout linear regulator, which comprises: a bandgap reference voltage source circuit, a CMOS two-stage error amplifier circuit, an adjustment tube, a frequency compensation circuit and a feedback circuit. The bandgap reference source circuit provides a voltage independent of the power supply voltage and ambient temperature; the bandgap reference voltage source circuit is connected to a CMOS two-stage error amplifier circuit; the CMOS two-stage error amplifier circuit is connected to a bandgap reference voltage source circuit and a feedback circuit and an adjustment tube; the frequency compensation circuit is connected to the adjustment tube; the adjustment tube is connected to the feedback circuit. The error amplification signal is generated by the CMOS two-stage error amplifier circuit; the adjustment tube is used to help feedback errors and reduce the voltage difference; the phase margin of the circuit is compensated by the frequency compensation circuit, including Miller compensation and ESR (Equivalent Series Resistance) compensation, so that it is relatively easy to meet the requirements of the phase margin; the feedback circuit is used to adjust the output voltage.

Description

technical field [0001] The invention relates to a linear regulator, in particular to a frequency compensation circuit and a bandgap reference circuit. Background technique [0002] A voltage stabilizer is a circuit that can stabilize the output voltage. It can automatically adjust the output voltage, stabilize the power supply voltage that fluctuates greatly or does not meet the working needs of the product within its set normal operating range, and provides a constant output voltage for the load. , so that the load can work normally under the rated working voltage. The low dropout linear regulator refers to the difference between the minimum input voltage and the stable output voltage. The smaller the difference, the larger the operating voltage range and the smaller the input requirements. [0003] From the perspective of technology, it mainly includes linear voltage regulators of bipolar technology, linear voltage regulators of CMOS technology and linear voltage regulato...

AI Technical Summary

Problems solved by technology

The conduction device working in the switch state is called a DC-DC regulator, and the conduction device works in a linear state is called a linear regulator. They have their own advantages and disadvantages: the biggest advantage of the DC-DC regulator is high efficiency , can not only step up but also step down, the disadvantages are low precision, large volume, low stability and high noise

The biggest advantage of a linear regulator is high precision, good stability, low noise, and small size. The disadvantage is that it has low efficiency and can only step down but not boost.

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