N-channel input pair voltage regulator with soft start and current limitation circuitry
AssigneeSTMicroelectronics (China) Investment Co., Ltd.
InventorsZhenghao CUI, Fei Wang, Ming Jiang
Life of this patent
Estimating the term…
Abstract
A voltage regulator includes two input pairs of opposite type transistors, p-type and n-type, to provide a soft-start functionality for gradually increasing the voltage regulator's output voltage from zero, or a voltage below the thresholds of the n-type transistors, to an operational voltage. The voltage regulator operates in a soft-start mode during which a variable input voltage signal is ramped up to allow the output voltage to reach the operational voltage, and a normal-operation mode during which the operational voltage is maintained.
Claims9
A method for operating a voltage regulator, comprising:
- generating a soft-start current in response to a difference between a soft-start feedback signal and a variable ramp signal;
- generating a control voltage in response to a difference between a normal operation feedback signal and a reference signal;
- using the control voltage to control a conductivity of a transistor to pass the soft-start current for output as a drive current for controlling generation of an output voltage;
- and
- controlling said variable ramp signal to:
- increase in voltage during a soft-start operating mode;
- and
- remain at a fixed voltage during a normal operating mode following said soft-start operating mode.
A method for operating a voltage regulator, comprising:
- generating an output current applied to an output node of the voltage regulator to produce an output voltage;
- generating a soft-start current in response to a difference between a soft-start feedback signal and a variable ramp signal, wherein the soft-start feedback signal is derived from the output voltage;
- passing the soft-start current through a source-drain path of a transistor;
- adjusting a magnitude of the soft-start current passing through a source-drain path of the transistor by generating a control voltage applied to the gate of the transistor, wherein the control voltage is responsive to a difference between a normal operation feedback signal and a reference signal, and where the normal operation feedback signal is derived from the output voltage;
- mirroring the soft-start current received from the source-drain path of the transistor to generate said output;
- and
- controlling said variable ramp signal to:
- increase in voltage during a soft-start operating mode;
- and
- remain at a fixed voltage during a normal operating mode following said soft-start operating mode.
A method for operating a voltage regulator to generate an output voltage signal, comprising:
- sourcing an output current to generate the output voltage signal;
- operating in a soft-start mode comprising:
- varying a variable ramp voltage signal to gradually increase from a starting voltage to an operational voltage during the soft-start mode;
- determining a first difference between a first feedback signal that is based on the output voltage signal and the variable ramp voltage signal;
- generating a soft start current in response to said first difference;
- and
- mirroring the soft start current to produce said output current;
- and
- operating in a normal-operation mode comprising:
- maintaining the operational voltage during the normal-operation mode;
- determining a second difference between a second feedback signal that is based on the output voltage signal and a reference signal;
- and
- controlling mirroring of the soft-start current in response to the second difference to produce said output current.
Dependencies are inferred from the claim text.