Circuit for regulating startup and operation voltage of an electronic device
AssigneeSTMicroelectronics International N.V.
InventorsHemant Shukla, Saurabh Kumar Singh, Nitin Bansal
Life of this patent
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Abstract
An electronic device includes a power supply, a ground, and an intermediate ground having a voltage less than a voltage of the power supply and greater than a voltage of the ground. The electronic device also includes an error amplifier having an input stage coupled between the power supply and the ground, and an output stage coupled between the power supply and the intermediate ground. A ballast transistor is coupled to receive an output from the error amplifier. A feedback circuit is coupled to an output of the ballast transistor to generate feedback signals, and the error amplifier operates in response to the feedback signals.
Claims27
An electronic device, comprising:
- a power supply node;
- a ground node;
- an intermediate ground node configured at a voltage between a voltage of the power supply node and a voltage at the ground node;
- and
- an error amplifier having an input stage coupled between the power supply node and the ground node, and an output stage coupled between the power supply node and the intermediate ground node.
A circuit, comprising:
- a power supply node;
- a ground node;
- an intermediate ground node having a voltage less than a voltage of the power supply node and greater than a voltage of the ground node;
- a first differential input stage having differential inputs coupled to receive a reference voltage and a second feedback voltage, and having a first tail;
- a second differential input stage having differential inputs coupled to receive an intermediate reference voltage and a first feedback voltage, and having a second tail;
- a first switch configured to couple the first tail of the first differential input stage to the ground node when in a normal operation mode and to decouple the first tail of the first differential input stage from the ground node when in a startup mode;
- a second switch configured to selectively couple the second tail of the second differential input stage to the ground node when in the startup mode and to decouple the second tail of the second differential input stage from the ground node when in the normal operation mode;
- and
- an output stage coupled between the power supply node and the intermediate ground node, and coupled to outputs of the first and second differential input stages.
A method of operating an electronic device, comprising:
- operating an error amplifier in a startup mode with inputs receiving an intermediate reference voltage and a first feedback voltage to generate an output signal;
- operating an error amplifier in a normal operation mode with inputs receiving a reference voltage and a second feedback voltage to generate the output signal;
- and
- driving a transistor of a low dropout amplifier with the output signal to generate an output voltage.
Dependencies are inferred from the claim text.