Low-dropout voltage regulator with a voltage slew rate efficient transient response boost circuit
First Claim
1. A voltage regulator comprising:
- an amplifier having an amplifier output;
a pass device having a first node coupled to the amplifier output for generating an output voltage via a second node of the pass device; and
a voltage control circuit for applying a voltage to the first node to accelerate a response time of the amplifier in enabling the output voltage to reach its final regulated output voltage, the voltage control circuit comprising a comparator having a negative input coupled to a positive input of the amplifier, and a switch device having a first switch node coupled to an output of the comparator, a second switch node coupled to an additional voltage, and a third switch node coupled to the amplifier output and the first node of the pass device to apply the additional voltage to the first node of the pass device.
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Abstract
A low-dropout (LDO) voltage regulator for generating an output voltage is disclosed. The voltage regulator includes a startup circuit, a curvature corrected bandgap circuit, an error amplifier, a metal oxide semiconductor (MOS) pass device and a voltage slew rate efficient transient response boost circuit. The MOS pass device has a gate node which is coupled to the output of the error amplifier, and a drain node for generating the output voltage. The voltage slew rate efficient transient response boost circuit applies a voltage to the gate node of the MOS pass device to accelerate the response time of the error amplifier in enabling the LDO voltage regulator to reach its final regulated output voltage when an output voltage drop occurs in the LDO voltage regulator.
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Citations
23 Claims
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1. A voltage regulator comprising:
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an amplifier having an amplifier output; a pass device having a first node coupled to the amplifier output for generating an output voltage via a second node of the pass device; and a voltage control circuit for applying a voltage to the first node to accelerate a response time of the amplifier in enabling the output voltage to reach its final regulated output voltage, the voltage control circuit comprising a comparator having a negative input coupled to a positive input of the amplifier, and a switch device having a first switch node coupled to an output of the comparator, a second switch node coupled to an additional voltage, and a third switch node coupled to the amplifier output and the first node of the pass device to apply the additional voltage to the first node of the pass device. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A voltage regulator comprising:
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a pass device having an output node for generating an output voltage; an amplifier having an amplifier output coupled to an input node of the pass device; and a voltage control circuit coupled to the amplifier output and the input node of the pass device, wherein the voltage control circuit is configured to apply a voltage to the input node of the pass device to accelerate a response time of the amplifier in enabling the output voltage to reach its final regulated output voltage, and the voltage control circuit comprises a comparator having a negative input that is coupled to a positive input of the amplifier, and a switch device having a first switch node coupled to an output of the comparator, a second switch node coupled to an additional voltage, and a third switch device node coupled to the amplifier output and the first node of the pass device to apply the additional voltage to the first node of the pass device. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16)
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17. A method comprising:
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generating a first control signal to control a gate of a transistor to adjust an output voltage to a full load regulated value; generating a transient response boost voltage, wherein the first control signal controls a pass device to deliver a maximum output current associated with the output voltage; and selectively applying the transient response boost voltage to the gate of the transistor to accelerate the rate at which the output voltage is adjusted to the full load regulated value. - View Dependent Claims (18, 22, 23)
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19. A voltage regulator comprising:
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an amplifier having an amplifier output; a first transistor having a gate coupled to the amplifier output for generating an output voltage via a node the first transistor; a comparator having an input coupled to an input of the amplifier, and an a comparator output; and a second transistor having a gate responsive to the comparator output to couple the gate of the first transistor to a voltage. - View Dependent Claims (20, 21)
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Specification