SWITCH-MODE POWER SUPPLY METHOD AND APPARATUS USING SWITCH-NODE FEEDBACK
First Claim
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1. Switch-mode power supply apparatus comprising:
- an electric circuit comprising a power input, a power output, and inductor positioned in series between the power input and the power output, an active switch positioned in series with the inductor to provide a switch-node that connects the active switch and the inductor, and bypass switch means connected between the switch-node and ground in parallel to the inductor for providing a current path between the inductor and ground when the active switch is turned off; and
switch control means for turning the active switch on and off periodically, including pulse width modulation control means for imposing a duty cycle on the switch to produce a desired output voltage at the power output, and switch-node feedback means for providing feedback from the switch-node to the pulse width modulation control means to maintain the desired output voltage.
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Abstract
Example switch mode power supplies, including buck converters, with indirect, switch-mode feedback for pulse width modulation and duty cycle control are described and shown. Non-idealities are corrected with several example compensation methods and apparatus, including current sense and corresponding voltage adjustment.
67 Citations
18 Claims
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1. Switch-mode power supply apparatus comprising:
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an electric circuit comprising a power input, a power output, and inductor positioned in series between the power input and the power output, an active switch positioned in series with the inductor to provide a switch-node that connects the active switch and the inductor, and bypass switch means connected between the switch-node and ground in parallel to the inductor for providing a current path between the inductor and ground when the active switch is turned off; and switch control means for turning the active switch on and off periodically, including pulse width modulation control means for imposing a duty cycle on the switch to produce a desired output voltage at the power output, and switch-node feedback means for providing feedback from the switch-node to the pulse width modulation control means to maintain the desired output voltage. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A method of pulse width modulation for controlling output voltage in a switch-mode power supply circuit that includes an inductor between a power input and a power output and an active switch connected via a switch-node to the inductor for imposing a duty cycle to control the output voltage, comprising:
generating a switch control signal that includes pulse width modulation for imposing an on-off duty cycle on the active switch to produce a desired output voltage; and
obtaining feedback of voltage at the switch-node as indicative of the output voltage, and adjusting the pulse width modulation of the control signal to maintain the voltage at the switch node at a desired level to produce the desired output voltage.- View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18)
Specification