System and method for providing digital pulse width modulation
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Accused Products
Abstract
A pulse width modulation system for use in a switching power supply circuit provides high-resolution pulse width modulated signals. The pulse width modulation system is configured to receive a control signal comprising a (m+n)-bit binary word and to provide a pulse width modulated signal with a predetermined average duty cycle having a resolution of substantially 2−(m+n). The pulse width modulation system includes a timing circuit for providing 2m timing signals, a dithering circuit, and a signal generator. Upon receiving the control signal, the dithering circuit is configured to provide a modified control signal, which comprises a series of up to 2n-bit binary words. The signal generator is configured to receive the timing signals and the modified control signal and to provide the pulse width modulated signal having a duty cycle, which, when averaged over 2n timing cycles, is approximately equal to the predetermined average duty cycle. The pulse width modulated signal is used by a switching power supply circuit to control at least one power switching device.
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Citations
48 Claims
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1-26. -26. (canceled)
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27. A pulse width modulation circuit comprising:
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a dithering circuit configured to receive a digital control word corresponding to a desired duty cycle and provide a modified control signal comprising plural digital control words;
a timing circuit configured to provide plural timing signals, each said timing signal comprising a voltage pulse corresponding to a respective one of the plural digital control words; and
a signal generator configured to receive said modified control signal and said timing signals, and providing a pulse width modulated signal having an average duty cycle that is substantially equal to the desired duty cycle. - View Dependent Claims (28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48)
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Specification