Low-dropout regulator with an improved power supply rejection ratio using feed-forward or bulk power supply ripple injection
OwnerFrancesco Spreafico, Andrea Baschirotto +2inventors
InventorsFrancesco Spreafico, Andrea Baschirotto, Richard Gaggl, Luca Sant
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Abstract
A low drop-out (LDO) voltage regulator circuit includes an LDO voltage regulator including a pass device coupled to a power supply voltage, wherein the pass device includes a bulk node; an amplifier having an input coupled to the power supply voltage; a first capacitor coupled between an output of the amplifier and the bulk node of the pass device; and a first resistor coupled between the bulk node of the pass device and the power supply voltage having a low ohmic value in a first operating mode and a high ohmic value in a second operating mode.
Claims20
A low drop-out (LDO) voltage regulator circuit comprising:
- an LDO voltage regulator comprising a pass device coupled to a power supply voltage, wherein the pass device comprises a bulk node;
- an amplifier having an input coupled to the power supply voltage;
- a first capacitor coupled between an output of the amplifier and the bulk node of the pass device;
- and
- a first resistor coupled between the bulk node of the pass device and the power supply voltage having a low ohmic value in a first operating mode and a high ohmic value in a second operating mode.
A low drop-out (LDO) voltage regulator circuit comprising:
- an LDO voltage regulator comprising a pass device coupled to a power supply voltage, wherein the pass device comprises a bulk node;
- an amplifier having an input coupled to the power supply voltage;
- a first capacitor coupled between an output of the amplifier and a current path node of the pass device;
- and
- a second capacitor coupled between the output of the amplifier and the power supply voltage.
A method for reducing a power supply rejection ratio (PSRR) of a low-dropout (LDO) voltage regulator including a flipped voltage follower (FVF) stage, the method comprising AC injecting an amplified replica of a power supply ripple signal into a node of the FVF stage.
Dependencies are inferred from the claim text.