Patent ID: 7211992
Filing Date: 2007-05-01
Classification: H02M

Abstract:
1. A switched-mode DC/DC converter producing at least one output voltage (Vout), comprising: At least one power stage (PS) for the purpose of converting an input voltage (Vin) into an output voltage (Vout), each power stage including at least one controllable switching device (CS); and A control device (CD) for the purpose of turning ON and turning OFF said controllable switching device, 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, a quantized ON time/OFF time pair from a working set of at least two quantized ON time/OFF time pairs, suitable for regulating the output voltage, and characterized in that the sum of the quantized ON time and OFF time of each pair (in said working 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 working 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.