System and method for providing digital pulse width modulation
First Claim
1. In a switching power supply system having at least one switching element, a control circuit for driving said at least one switching element comprises:
- a dithering circuit configured to receive a control signal comprising a (m+n)-bit binary word, where m and n are positive integers, and to provide a modified control signal comprising a series of up to 2n m-bit binary words;
a timing circuit configured to provide 2m timing signals and to communicate at least one of said timing signals to said dithering circuit; and
a signal generator configured to receive said modified control signal and said timing signals and to provide a pulse width modulated signal to said at least one switching element, said pulse width modulated signal configured to activate said at least one switching element with an average duty cycle that is substantially equal to a quotient of a decimal equivalent of the (m+n)-bit binary word and 2(m+n).
12 Assignments
0 Petitions
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 m-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.
-
Citations
26 Claims
-
1. In a switching power supply system having at least one switching element, a control circuit for driving said at least one switching element comprises:
-
a dithering circuit configured to receive a control signal comprising a (m+n)-bit binary word, where m and n are positive integers, and to provide a modified control signal comprising a series of up to 2n m-bit binary words;
a timing circuit configured to provide 2m timing signals and to communicate at least one of said timing signals to said dithering circuit; and
a signal generator configured to receive said modified control signal and said timing signals and to provide a pulse width modulated signal to said at least one switching element, said pulse width modulated signal configured to activate said at least one switching element with an average duty cycle that is substantially equal to a quotient of a decimal equivalent of the (m+n)-bit binary word and 2(m+n). - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21)
-
-
22. A method for providing pulse width modulated signals to control power flow from an input source of a switching power supply circuit to the output source of the switching power supply circuit, comprising:
-
receiving a control signal comprising a (m+n)-bit binary word, where m and n are positive integers;
dithering said control signal to provide a modified control signal comprising a series of up to 2n m-bit binary words;
providing 2m timing signals;
generating a pulse width modulated signal with an average duty cycle that is substantially equal to a quotient of a decimal equivalent of the (m+n)-bit binary word and 2(m+n); and
controlling operation of a power switch associated with the switching power supply circuit using said pulse width modulated signal. - View Dependent Claims (23, 24, 25, 26)
-
Specification