High resolution digital pulse width modulator for DC-DC voltage converter
First Claim
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1. A method of high resolution pulse width modulation, comprising the steps of:
- (a) splitting a plurality of digital code words, each into a most significant bits portion and a least significant bits portion;
(b) generating a plurality of pulse width modulation (PWM) signals having at least one prescribed pulse width parameter defined at least in part in accordance with respective ones of said most significant bits portion, wherein a first of said plurality of PWM signals has a first pulse width parameter defined by a first of said most significant bits portion; and
(c) generating a next of said plurality of PWM signals, said next PWM signal having an associated pulse width parameter based on a next of said most significant bits portion adjusted by said first least significant bits portion.
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Abstract
A digitally-implemented pulse width modulation (PWM) signal generator forms the PWM pulse width as a rational number based on full cycles of a PWM reference clock, and offers a very high effective resolution of the PWM pulse signal that is compatible with multiphase DC-DC converters. Being totally digital allows digital error accumulation and correction to occur at the point of origin of the PWM signal, well upstream of the relatively slow voltage control feedback loop. Quantization errors are corrected before they can accumulate in the converter'"'"'s DC output voltage.
40 Citations
29 Claims
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1. A method of high resolution pulse width modulation, comprising the steps of:
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(a) splitting a plurality of digital code words, each into a most significant bits portion and a least significant bits portion; (b) generating a plurality of pulse width modulation (PWM) signals having at least one prescribed pulse width parameter defined at least in part in accordance with respective ones of said most significant bits portion, wherein a first of said plurality of PWM signals has a first pulse width parameter defined by a first of said most significant bits portion; and (c) generating a next of said plurality of PWM signals, said next PWM signal having an associated pulse width parameter based on a next of said most significant bits portion adjusted by said first least significant bits portion. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22)
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23. A method of generating a regulated direct current (DC) output voltage comprising the steps of:
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(a) coupling a supply voltage to a DC-DC converter that is operative to generate a regulated output voltage derived from said supply voltage, said DC-DC converter having a pulse width modulation (PWM) generator which generates a PWM switching signal that switchably controls operation of a switching circuit containing electronic power switching devices coupled between respective power supply terminals, a common node thereof being coupled to an output voltage terminal; and (b) controlling the operation of said PWM generator by (b1) splitting a plurality of digital code words, each into a most significant bits portion and a least significant bits portion; (b2) generating a plurality of pulse width modulation (PWM) signals having at least one prescribed pulse width parameter defined at least in part in accordance with respective ones of said most significant bits portions, wherein a first of said plurality of PWM signals has a first pulse width parameter defined by a first of said most significant bits portion; and (b3) generating a next of said plurality of PWM signals, said next PWM signal having an associated pulse width parameter based on a next of said most significant bits portion adjusted by said first least significant bits portions. - View Dependent Claims (24, 25)
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26. An apparatus for generating a regulated direct current (DC) output voltage comprising:
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a DC-DC converter that is operative to generate a regulated output voltage derived from said supply voltage, said DC-DC converter including a pulse width modulation (PWM) generator which generates a PWM switching signal that switchably controls operation of a switching circuit containing electronic power switching devices coupled between respective power supply terminals, a common node thereof being coupled to an output voltage terminal; and a controller which is operative to control the operation of said PWM generator by splitting a plurality of digital code words, each into a most significant bits portion and a least significant bits portion, generating a plurality of pulse width modulation (PWM) signals having at least one prescribed pulse width parameters defined at least in part in accordance with respective ones of said most significant bits portion, wherein a first of said plurality of PWM signals has a first pulse width parameter defined by a first of said most significant bits portion; and
generating a next of said plurality of PWM signals, said next PWM signal having an associated pulse width parameter based on a next of said most significant bits portion adjusted by said first least significant bits portion. - View Dependent Claims (27, 28, 29)
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Specification