US 2025/0165019 A1 · HYBRID LDO REGULATOR WITH FINE LOOP PRESET

Abstract

A low dropout regulator with fine loop preset including a coarse resolution regulator and a fine resolution regulator. The coarse resolution regulator adjusts a digital control value in response to an output transient to control a coarse output driver to regulate an output voltage with coarse resolution. The coarse resolution regulator eventually enters a limit-cycle oscillation mode with a corresponding duty cycle. The fine resolution regulator is disabled when the digital control value initially changes, is preset based on the duty cycle of the digital control value when in the limit-cycle oscillation mode, and is re-enabled after being preset to drive at least one fine output driver to regulate the output voltage with fine resolution. The preset provides a closer estimate of the supplemental current needed to meet the output load level when turned on after an output load transient to achieve less output ripple voltage.

Claims20

Dependent claims

A low dropout regulator, comprising:

a coarse resolution regulator, comprising:
a coarse output driver coupled to an output node that develops an output voltage, wherein the coarse output driver is configured to be controlled by a digital control value;
and
a digital controller that is configured to adjust the digital control value in response to an output transient to regulate the output voltage with coarse resolution, wherein the digital controller is configured to enter a limit-cycle oscillation mode by toggling the digital control value at a corresponding duty cycle;
and
a fine resolution regulator, comprising:
a fine output driver receiving an analog control value and coupled to the output node;
an analog controller that is configured to adjust the analog control value to regulate the output voltage with fine resolution;
and
a preset controller that is configured to disable the fine resolution regulator when the digital control value changes in response to an output transient, that is configured to calculate the duty cycle of the digital control value during the limit-cycle oscillation mode, and that is configured to preset the fine output current driver based on the calculated duty cycle and to re-enable the fine resolution regulator.

7 more elements

A method of operating a low dropout regulator that includes a coarse resolution regulator and a fine resolution regulator, comprising:

adjusting a digital control value in response to an output transient to control a coarse output driver to regulate an output voltage on an output node with coarse resolution;
disabling the fine resolution regulator upon detecting the digital control value being adjusted;
detecting when the digital control value indicates limit-cycle oscillation mode in which the digital control value toggles with a corresponding duty cycle;
calculating the duty cycle of the digital control value during the limit-cycle oscillation mode;
presetting the fine resolution regulator based on the calculated duty cycle;
and
re-enabling the fine resolution regulator after presetting the fine resolution regulator to drive at least one fine output driver to regulate the output voltage with fine resolution.

4 more elements

Dependencies are inferred from the claim text.

Hybrid ldo regulator with fine loop preset

Life of this patent

Hybrid ldo regulator with fine loop preset

Life of this patent

Abstract

Claims20