| US 7,532,082 B2 | ||
| Synchronization circuit for synchronizing PWM modulators | ||
| Martin Clara, Villach (Austria); Thomas Poetscher, Villach (Austria); Sergio Walter, Villach (Austria); and Andreas Wiesbauer, Poertschach (Austria) | ||
| Assigned to Infineon Technologies AG, Munich (Germany) | ||
| Filed on Nov. 06, 2006, as Appl. No. 11/593,235. | ||
| Claims priority of application No. 10 2005 052 702 (DE), filed on Nov. 04, 2005. | ||
| Prior Publication US 2007/0104266 A1, May 10, 2007 | ||
| Int. Cl. H03K 7/08 (2006.01) | ||
| U.S. Cl. 332—109 [340/825.19; 375/238] | 10 Claims |
| 1. A synchronization circuit for synchronizing at least two self-oscillating PWM modulators, each outputting a respective
pulse-width-modulated output signal comprising signal pulses with signal pulse centers; said synchronizing circuit shifting
the timings of said signal pulses relative to one another such that said signal pulse centers are in sync; wherein each of
said self-oscillating PWM modulators comprises:
a signal input for receiving an analogue input signal;
an input signal filter producing a filtered difference signal by filtering a difference signal between said analogue input
signal and a feedback signal;
a comparator for generating a comparator output signal by comparing said filtered difference signal with a reference voltage;
a delay circuit for generating a delayed comparator output signal by delaying said comparator output signal on the basis of
a synchronization control signal;
a power stage amplifying for generating an amplified comparator output signal by amplifying said delayed comparator output
signal;
a feedback filter for generating a feedback signal for said input signal filter by filtering said amplified comparator output
signal; and
a signal output outputting said amplified comparator output signal as said respective pulse-width-modulated output signals
of the relevant of said PWM modulators.
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