Low Pass Filter Low Drop-out Voltage Regulator
AssigneeFreescale Semiconductor, Inc.
InventorsDavid Schlueter, Jerome Enjalbert
Life of this patent
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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 regulator comprising:
- a first differential amplifier;
- a second differential amplifier arranged in parallel with the first differential amplifier;
- a feedback loop of the low drop-out voltage regulator, comprising a first feedback signal coupled to the first differential amplifier and a second feedback signal coupled to the second differential amplifier;
- and
- a low pass filter in the feedback loop.
A method for producing a controlled output voltage, the method comprising:
- dividing the controlled output voltage;
- low pass filtering the divided output voltage;
- comparing a reference signal, the divided output voltage, and the low pass filtered signal with a first differential amplifier and a second differential amplifier;
- producing a comparison signal;
- and
- generating the controlled output voltage based on the comparison signal.
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, comprising a voltage divider and a low pass filter and operable to generate the feedback signal.
Dependencies are inferred from the claim text.