Method for adaptive compensation of linear voltage regulators
AssigneepSemi Corporation
InventorGary Chunshein Wu
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Abstract
Devices and methods to design voltage regulators requiring lower power consumption, wide output current and input voltage range, low dropout, and small footprint. The disclosed methods and devices provide solutions to stabilize such regulators in the presence of widely varying loads by tracking a pole of the transfer function, the pole of the transfer function corresponding to a combination of the load capacitance and the load resistance.
Claims20
A low drop out voltage regulator (LDO) configured to receive an input voltage at an input terminal and to output an output voltage to an output terminal connectable to a load, comprising:
- (i) a feedback circuit configured to generate a load current as a function of the output voltage;
- and (ii) a tracking circuit;
- wherein:
- (a) a ratio of the output voltage to the input voltage has a transfer function comprising a load pole and a zero;
- and
- (b) the tracking circuit is configured to adjust the zero to track movements of the load pole due to variations of the load current.
A voltage tracking circuit comprising:
- a first transistor and a second transistor;
- a first electronic circuit coupled to the first transistor;
- and
- a second electronic circuit coupled to the second transistor
- wherein:
- the first electronic circuit is configured to generate a first current as a function of a gate-source voltage of the first transistor;
- and
- the second electronic circuit is configured to receive a second current being a mirror of the first current, thereby generating a voltage across a gate-source of the second transistor, the voltage being proportional to the gate-source voltage of the first transistor.
A method of stabilizing a feedback loop in a low dropout voltage regulator (LDO) comprising the steps of:
- providing an input voltage to the LDO;
- providing a load;
- generating an output voltage and a load current, wherein a ratio of the output voltage to the input voltage has a transfer function;
- varying a zero of the transfer function with the load current to track a pole of the transfer function, and
- adjusting the load current based on the output voltage, thereby regulating an output power.
Dependencies are inferred from the claim text.