Patent ID: 7109695
Filing Date: 2006-09-19
Classification: H02M

Abstract:
1. A method of converting an input voltage to an output voltage by means of a switched-mode DC/DC converter; the input voltage (Vin) being converted into an output voltage (Vout) with the aid of a power stage (PS), including at least one controllable switching device (CS), which is turned ON and turned OFF by a control device (CD) characterized in that Owing to the temporal resolution of the control device, Δt, both the turn ON and turn OFF times of the controllable switching device (CS) are constrained to be integral multiples of Δt; and A duty cycle control mechanism (DC) for controlling the duty cycle of said controllable switching device, comprising: A mechanism for estimating output voltage error, the output voltage error being the difference between the uncorrupted output voltage and the desired output voltage (Vdo); and A selector mechanism (SM) for determining, for the current output voltage error estimate, the turn OFF and turn ON times of said controllable switching device by choosing, cycle by cycle, an ON time/OFF time pair from a set of at least two quantized ON time/OFF time pairs, suitable for controlling said controllable switching device and characterized in that the sum of the quantized ON time and OFF time of each pair (in said set) is constrained to a set of discrete values {Tswi} (i=1, 2, . . . I) where I is a positive integer and Tswi is an integral multiple of Δt; choosing in such a manner that the amplitude of the output voltage error is continually minimized, and A mechanism for dynamically adjusting the set of at least two quantized ON time/OFF time pairs to compensate for variations in input voltage (Vin) as well as the load-dependent effects of parasitics.