Low pass filter low drop-out voltage regulator
AssigneeFreescale Semiconductor, Inc.
InventorsDavid Schlueter, Jerome Enjalbert
Life of this patent
Estimating the term…
Abstract
A low dropout voltage regulator is described having a pass device, differential amplifiers, and a feedback loop including a low pass filter. Two differential amplifiers arranged in parallel coupled to the low pass filter in the feedback loop provide a specified and stable DC voltage whose input-to-output voltage difference is low. Improved stability, reduced die area, improved power supply rejection ratio, increased bandwidth, decreased power consumption, and better electrostatic discharge (ESD) protection may result.
Claims20
A low drop-out voltage comprising:
- a first differential amplifier, wherein a reference signal is coupled to a non-inverting input of the first differential amplifier;
- a second differential amplifier arranged in parallel with the first differential amplifier;
- and
- a feedback loop of the low drop-out voltage regulator, comprising:
- a voltage divider operable to produce a first feedback signal, wherein the first feedback signal is coupled to an inverting input of the first differential amplifier, an inverting input of the second differential amplifier, and a low pass filter;
- and
- the low pass filter operable to produce a second feedback signal, wherein the second feedback signal is coupled to a non-inverting input of the second differential amplifier.
A low drop-out voltage regulator, comprising:
- a pass circuit operable to generate a controlled output voltage;
- a differential amplifier coupled to the pass circuit, a reference signal, and a feedback signal, the differential amplifier operable to compare the reference signal and the feedback signal;
- and
- a feedback circuit coupled to the pass circuit and the differential amplifier, the feedback circuit operable to generate the feedback signal and comprising:
- a voltage divider;
- a low pass filter;
- a first feedback loop coupled between an output of the pass circuit and the differential amplifier, the first feedback loop comprising the voltage divider;
- and
- a second feedback loop coupled between the output of the pass circuit and the differential amplifier, the second feedback loop comprising the voltage divider and the low pass filter.
A low drop-out voltage regulator comprising:
- a first differential amplifier, wherein a reference signal is coupled to a non-inverting input of the first differential amplifier;
- a second differential amplifier arranged in parallel with the first differential amplifier, wherein the reference signal is coupled to an inverting input of the second differential amplifier;
- and
- a feedback loop of the low drop-out voltage regulator, comprising:
- a voltage divider operable to produce a first feedback signal, wherein the first feedback signal is coupled to an inverting input of the first differential amplifier and a low pass filter;
- and
- the low pass filter operable to produce a second feedback signal, wherein the second feedback signal is coupled to a non-inverting input of the second differential amplifier.
Dependencies are inferred from the claim text.