Apparatus and method for noise sensitivity improvement to a switching system
AssigneeRichtek Technology Corporation
InventorsJian-Rong Huang, Kuo-Ping Liu, Kent Huang, Liang-Pin Tai
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Abstract
In a noise sensitivity improved switching system and method thereof, comprised sensing the output voltage of the switching system to generate a feedback signal, respectively amplifying the feedback signal by two gains to generate two signals in phase or out of phase, filtering one of the two amplified signals, and summing or comparing the filtered signal and the other one, thereby reducing the noise interference to the switching system.
Claims15
An apparatus for noise sensitivity improvement to a switching system including a comparator to generate a comparator signal to drive an output stage to generate an inductor current to derive an output voltage, and a voltage sense circuit to sense said output voltage to generate a feedback signal, said apparatus comprising:
- a first amplifier having a first gain for amplifying said feedback signal to generate a first signal;
- a second amplifier having a second gain for amplifying said feedback signal to generate a second signal;
- a filter for filtering said second signal;
- and
- a summing circuit for combining said first signal and said filtered second signal to generate a third signal to said comparator, said third signal including a level shifted version of a noise component when present in said feedback signal.
A method for noise sensitivity improvement to a switching system including a comparator to generate a comparator signal to drive an output stage to generate an inductor current to derive an output voltage, and a voltage sense circuit to sense said output voltage to generate a feedback signal, said method comprising the steps of:
- respectively amplifying said feedback signal by a first gain and a second gain for generating a first signal and a second signal;
- filtering said second signal;
- and
- combining said first signal and said filtered second signal for generating a third signal to said comparator, said third signal including a level shifted version of a noise component when present in said feedback signal.
An apparatus for noise sensitivity improvement to a switching system to generate an inductor current to derive an output voltage by driving an output stage with a comparator signal, and a voltage sense circuit to sense said output voltage to generate a feedback signal, said apparatus comprising:
- an amplifier circuit for respectively amplifying a differential of said feedback signal and a first reference by a first gain and by a second gain to generate a first signal and a second signal with a phase difference to said first signal;
- a voltage generator for providing a second reference for level shifting of said first and second signals;
- a filter for filtering said level-shifted second signal;
- and
- a comparator for comparing said level-shifted first signal with said filtered level-shifted second signal to generate said comparator signal.
A method for noise sensitivity improvement to a switching system to generate an inductor current to derive an output voltage by driving an output stage with a comparator signal, and a voltage sense circuit to sense said output voltage to generate a feedback signal, said method comprising the steps of:
- respectively amplifying a differential of said feedback signal and a first reference by a first gain and by a second gain for generating a first signal and a second signal with a phase difference to said first signal;
- providing a second reference for level shifting of said first and second signals;
- filtering said level-shifted second signal;
- and
- comparing said level-shifted first signal with said filtered level-shifted second signal to generate said comparator signal.
Dependencies are inferred from the claim text.