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US 9,471,074 B2Granted
USB regulator with current buffer to reduce compensation capacitor size and provide for wide range of ESR values of external capacitor
AssigneeMicrochip Technology Incorporated
InventorsHuamin Zhou, Woowai Martin, Cristian Albina, Fritz Schlunder, Minh Le
Life of this patent
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Abstract
A voltage regulator has a large gm current buffer driver added between a first stage of an operation amplifier and a last stage power transistor. This current buffer allows a significant reduction in the maximum internal and external compensation capacitances needed for regulator stability. The current buffer compensation circuit allows a wide range of external capacitor sizes that increases the flexibility in choosing the external capacitor types (with low to high ESR ratings).
Claims18
A voltage regulator, comprising:
- an operational amplifier;
- a gm enhanced current buffer driver;
- a biasing circuit coupled to the current buffer driver to set a biasing ratio for gm-boost of the current buffer driver;
- an enable/disable function to enable/disable the biasing circuit for reducing standby current:
- an output power driver, wherein the current buffer driver is coupled between the operational amplifier and the output power driver;
- a current feedback circuit coupled between the output power driver and the current buffer driver;
- and
- a feedback loop coupled between the output power driver and the operational amplifier.
5 more elements
Dependencies are inferred from the claim text.