Low dropout linear regulator with internally compensated effective series resistance
First Claim
1. A voltage regulator circuit having an internally compensated effective series resistance, the circuit comprising:
- a control circuit to generate an output current at a regulated output voltage based on a reference voltage, the control circuit compromising;
a first amplifier circuit,a feedback element coupled to feedback the output voltage to an input of the first amplifier circuit, anda compensation circuit coupled to the control circuit and to the feedback element to couple the internally compensated effective series resistance into the control circuit, the compensation circuit comprising;
a first device, arranged to generate a first sensed current proportional to a current through an N-type pass-device,a second device, coupled to the feedback element and to the input of the first amplifier circuit, the second device being arranged to generate a second sensed current proportional to the current through the N-type pass-device, anda bias circuit coupled to sink the first sensed current and the second sensed current to reduce a bias voltage across the feedback element below a threshold voltage.
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Accused Products
Abstract
A voltage regulator circuit having an internally compensated effective series resistance includes a control circuit to generate an out current at a regulated output voltage based on a reference voltage. The control circuit includes an amplifier, a resistive element to feedback output voltage to an input of the amplifier, and a compensation circuit to couple the internally compensated effective series resistance into the control circuit. The compensation circuit includes a first current sense device to generate a first sensed current proportional to a current through an N-type pass device, a second current sense device arranged to generate a second sensed current proportional to the current through the N-type pass device, and a bias circuit coupled to sink the first sensed current and the second sensed current to reduce a bias voltage across the resistive element below a threshold voltage.
13 Citations
24 Claims
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1. A voltage regulator circuit having an internally compensated effective series resistance, the circuit comprising:
a control circuit to generate an output current at a regulated output voltage based on a reference voltage, the control circuit compromising; a first amplifier circuit, a feedback element coupled to feedback the output voltage to an input of the first amplifier circuit, and a compensation circuit coupled to the control circuit and to the feedback element to couple the internally compensated effective series resistance into the control circuit, the compensation circuit comprising; a first device, arranged to generate a first sensed current proportional to a current through an N-type pass-device, a second device, coupled to the feedback element and to the input of the first amplifier circuit, the second device being arranged to generate a second sensed current proportional to the current through the N-type pass-device, and a bias circuit coupled to sink the first sensed current and the second sensed current to reduce a bias voltage across the feedback element below a threshold voltage. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A method of operating a voltage regulator circuit having an internally compensated effective series resistance, the method comprising:
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supplying a load current at a regulated output voltage in response to a reference voltage using an error amplifier and an N-type field effect transistor (NFET); coupling, using a resistive element, the output voltage to an input of the error amplifier to generate a control loop; and coupling an internally compensated effective series resistance into the control loop using the resistive element and a compensation circuit, the compensation circuit selectively sinking a sensed current generated based on a current through the NFET to reduce a direct current bias voltage across the resistive element below a threshold voltage. - View Dependent Claims (12, 13, 14, 15)
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16. A voltage regulator circuit having an internally compensated effective series resistance, the circuit comprising:
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an amplifier circuit; a first N-type field effect transistor (NFET), the first NFET being driven by the amplifier to generate a current at a regulated output voltage in response to a reference voltage; a second NFET coupled to the amplifier to generate a first sensed current based on a current flowing through the first NFET; a third NFET coupled to the amplifier to generate a second sensed based on the current flowing through the first NFET; a resistor coupled to feedback the output voltage to an input of the amplifier and to a source of the second NFET; and a driver circuit configured to control the first sensed current and the second sensed current to reduce a direct current bias voltage across the resistor below a threshold voltage. - View Dependent Claims (17, 18, 19)
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20. A voltage regulator circuit having an internally compensated effective series resistance, the circuit comprising:
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an amplifier circuit; a pass element comprising an N-type transistor, the pass circuit driven by the amplifier to generate a current at a regulated output voltage in response to a reference voltage; a first sensing element to generate a first sensed current based on a current flowing through the pass circuit; a second sensing element to generate a second sensed current based on the current flowing through the pass circuit; a feedback element to feedback the output voltage to an input of the amplifier and to a source of the first sensing element; and a driver circuit configured to control the first sensed current and the second sensed current to reduce a direct current bias voltage across the feedback element below a threshold voltage. - View Dependent Claims (21, 22, 23, 24)
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Specification