Voltage regulator with capacitance multiplier
AssigneeDialog Semiconductor (UK) Limited
InventorChi-Chia Huang
Life of this patent
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Abstract
A voltage regulator and a method for regulating an output voltage are presented. The voltage regulator includes a frequency compensation circuit having a first capacitor coupled to a capacitance multiplier. The capacitance multiplier has a second capacitor coupled to a voltage amplifier. The voltage amplifier amplifies a first voltage that is a function of the output voltage. The advantage of this regulator and method is that it allows increasing the total capacitance of the frequency compensation circuit without unduly increasing the size of the regulator. Another advantage is the allowance of changing the amplification factor without affecting the DC gain.
Claims14
A voltage regulator for providing an output voltage at an output terminal via an output switch, the voltage regulator comprising
- an input stage coupled to a controller at an input node, the controller being adapted to control the output switch;
- a frequency compensation circuit having a first capacitor coupled to a capacitance multiplier, the first capacitor having a first terminal coupled to the input node and a second terminal coupled to the output terminal;
- wherein the capacitance multiplier comprises a second capacitor coupled to an output of a voltage amplifier configured to amplify a difference voltage that is function of the output voltage;
- wherein the voltage amplifier comprises a voltage-to-current converter coupled to a current-to-voltage converter;
- the voltage to current converter being adapted to receive a feedback voltage and a reference voltage and to provide a current to the current to voltage converter, the current being proportional to a difference between the feedback voltage and the reference voltage;
- wherein the second capacitor has a first terminal connected to the input node and a second terminal coupled to the output of the current-to-voltage converter.
A method of regulating a voltage comprising the steps of:
- providing a voltage regulator for providing an output voltage at an output terminal via an output switch;
- wherein the voltage regulator comprises an input stage coupled to a controller at an input node, the controller being adapted to control the output switch and a frequency compensation circuit having a first capacitor coupled to a capacitance multiplier, the first capacitor having a first terminal coupled to the input node and a second terminal coupled to the output terminal;
- the capacitance multiplier comprising a second capacitor coupled to an output of a voltage amplifier;
- and
- amplifying a difference voltage that is function of the output voltage
- wherein the voltage amplifier comprises a voltage-to-current converter coupled to a current-to-voltage converter;
- the voltage to current converter being adapted to receive a feedback voltage and a reference voltage and to provide a current to the current to voltage converter, the current being proportional to a difference between the feedback voltage and the reference voltage;
- wherein the second capacitor has a first terminal connected to the input node and a second terminal coupled to the output of the current to voltage converter.
Dependencies are inferred from the claim text.