Gain limiter
AssigneeDialog Semiconductor (UK) Limited
InventorMityu Mitev
Life of this patent
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Abstract
An LDO regulator for generating an output voltage at an output node of the LDO controller based on an input voltage received at an input node of the LDO controller is described. The LDO controller comprises a first amplifier stage, a driver stage, a second amplifier stage coupled between the drive stage and the output node, a feedback stage coupled between the output node and the first amplifier stage, and a gain limiter stage coupled between the first amplifier stage and the driver stage at an intermediate node for lowering a loop gain of the LDO regulator. A corresponding method for operating an LDO regulator is further described.
Claims16
A low dropout, LDO, regulator for generating an output voltage at an output node of the LDO regulator based on an input voltage received at an input node of the LDO regulator, the LDO regulator comprising:
- a first amplifier stage;
- a driver stage;
- a second amplifier stage coupled between the driver stage and the output node;
- a feedback stage coupled between the output node and the first amplifier stage;
- and
- a gain limiter stage coupled between the first amplifier stage and the driver stage at an intermediate node for lowering a regulation loop gain of the LDO regulator,
- wherein the gain limiter stage comprises first and second current mirrors,
- wherein one branch of the first current mirror and one branch of the second current mirror are coupled to the intermediate node;
- wherein the gain limiter stage further comprises a capacitive element coupled in parallel with a diode-connected switching element of the first current mirror;
- and
- wherein a capacitance of the capacitive element is set such that a current of a diode-connected switching element of the second current mirror is partially or fully compensated at low frequency, and/or is not, or is less, compensated at 0 dB gain frequency.
A gain limiter for use in a low dropout, LDO, regulator,
- wherein the gain limiter comprises first and second current mirrors;
- wherein one branch of the first current mirror and one branch of the second current mirror are coupled to an intermediate node between a first amplifier stage and a driver stage of the LDO regulator;
- and
- wherein the gain limiter is configured for lowering a regulation loop gain of the LDO regulator;
- wherein the gain limiter stage further comprises a capacitive element coupled in parallel with a diode-connected switching element of the first current mirror;
- and
- wherein a capacitance of the capacitive element is set such that a current of a diode-connected switching element of the second current mirror is partially or fully compensated at low frequency, and/or is not, or is less, compensated at 0 dB gain frequency.
A method for operating a low dropout, LDO, regulator configured for generating an output voltage at an output node of the LDO regulator based on an input voltage received at an input node of the LDO regulator, the method comprising:
- providing a first amplifier stage;
- providing a driver stage;
- providing and coupling a second amplifier stage between the driver stage and the output node;
- providing and coupling a feedback stage between the output node and the first amplifier stage;
- and
- providing and coupling a gain limiter stage between the first amplifier stage and the driver stage at an intermediate node for lowering a regulation loop gain of the LDO regulator,
- wherein the gain limiter stage comprises first and second current mirrors,
- wherein one branch of the first current mirror and one branch of the second current mirror are coupled to the intermediate node;
- wherein the gain limiter stage further comprises a capacitive element coupled in parallel with a diode-connected switching element of the first current mirror;
- and
- wherein a capacitance of the capacitive element is set such that a current of a diode-connected switching element of the second current mirror is partially or fully compensated at low frequency, and/or is not, or is less, compensated at 0 dB gain frequency.
Dependencies are inferred from the claim text.