DIGITALLY ASSISTED REGULATION FOR AN INTEGRATED CAPLESS LOW-DROPOUT (LDO) VOLTAGE REGULATOR
First Claim
1. A method for low-dropout regulation, the method comprising:
- enabling a digital to analog converter (DAC) in response to an advance notification signal supplied by a system circuit, wherein the advance notification signal indicates a change in load requiring increased current is to begin in a predetermined period; and
combining a current provided by the DAC with a current provided by a low-dropout (LDO) regulator to supply the system circuit, wherein voltage undershoot to the system circuit is reduced or removed.
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Accused Products
Abstract
Techniques are described that embed a digital assisted regulator with an LDO regulator on a chip without requiring a capacitor external to the chip and to regulate a voltage without undershoot. The digital assisted regulator responds to information regarding operation of the LDO regulator and to a signal that provides advance notification of a load change. When the advance notification signal is received, the digital assisted regulator pulls a circuit'"'"'s supply voltage up to a chip'"'"'s incoming supply voltage. When the correct operating voltage has been reached and any undershoot problem removed, the digital assisted regulator balances the current it provides with the current provided by the LDO regulator, to allow a quick response time for other load changes. Also, bandwidth of an LDO regulator may be expanded by use of an advance notice signal to increase bias current of an LDO output device to meet an upcoming load change.
59 Citations
21 Claims
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1. A method for low-dropout regulation, the method comprising:
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enabling a digital to analog converter (DAC) in response to an advance notification signal supplied by a system circuit, wherein the advance notification signal indicates a change in load requiring increased current is to begin in a predetermined period; and combining a current provided by the DAC with a current provided by a low-dropout (LDO) regulator to supply the system circuit, wherein voltage undershoot to the system circuit is reduced or removed. - View Dependent Claims (2, 3, 4, 5, 6)
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7. An apparatus for low-dropout regulation, the apparatus comprising:
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a low-dropout (LDO) regulator configured to provide linear regulation of voltage and current; a digital assisted regulator coupled to the LDO regulator and configured to provide digital assisted regulation of voltage and current; and a system circuit coupled to the digital assisted regulator and to the LDO regulator to receive supply voltage and current and having an advance notification circuit that is configured to notify the digital assisted regulator of an impending load change in time for the digital assisted regulator to supply current to the system circuit required by the load change. - View Dependent Claims (8, 9, 10, 11, 12, 13, 14, 15)
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16. An apparatus for system assisted low-dropout regulation, the apparatus comprising:
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a system circuit having an advance notification circuit configured to generate an advance notification signal that a load change is to occur in a predetermined time period; and a low-dropout (LDO) regulator for providing linear regulation of voltage and current to the system circuit, coupled to the system circuit to receive the advance notification signal and expand the bandwidth of the LDO regulator during the time of the load change in response to the advance notification signal. - View Dependent Claims (17, 18)
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19. A computer readable non-transitory medium encoded with computer readable program data and code, the program data and code when executed operable to:
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enable a digital to analog converter (DAC) in response to an advance notification signal supplied by a system circuit, wherein the advance notification signal indicates a change in load requiring increased current is to begin in a predetermined period; and combine a current provided by the enabled DAC with a current provided by a low-dropout (LDO) regulator to supply the system circuit, wherein voltage undershoot to the system circuit is reduced or removed.
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20. An apparatus for low-dropout regulation, the apparatus comprising:
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means for digital assisted regulation of a voltage and current; means for linear regulation of a voltage and current coupled to the digital regulation means and configured to operate in conjunction with the digital regulation means; and means for providing an advance notification to the digital regulation means of an impending load change in time to supply current to the system circuit required by the load change.
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21. An apparatus for system assisted low-dropout regulation, the apparatus comprising:
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means to generate an advance notification signal that a load change is to occur in a predetermined time period; and means to receive the advance notification signal and expand the bandwidth of the LDO regulator during the time of the load change in response to the advance notification signal.
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Specification