International Business Machines Corporation

James O Groves, Jr

Stephen F Newton

Randhir Singh Malik

Bruce M Cassidy

Jonathan James Hurd

William S Blocher

A circuit for providing an output current proportional to a first voltage raised to a fractional exponential power divided by a second voltage raised to a fractional exponential power, is supplied. The circuit has four strings of series connected pn junctions. The first and second voltages are connected to the first and fourth string, respectively. A reference current is provided to the second string, while the third string provides the output current. The number of pn junctions are chosen to give the desired fractional exponents of the two voltages while the number of pn junctions in the third string is selected to adjust for the number of pn junctions in the other strings.

Voltage ratio to current circuit

In critically continuous boost converters used to achieve high power factor and low input current harmonic distortion, a power FET is driven by a pulse generator whose on time is essentially constant over a single line cycle. Off time is terminated when current in the inductor falls to zero and the voltage on the side of the inductor not connected to the input voltage is less that the input voltage. A delay causes turn on to occur at the minimum of the voltage ring to minimize turn on switching losses. At voltages when the input voltage is less than one half of the output voltage part of the on time, turn on occurs with negative current flowing through the FET power switch and the inductor. Part of the turn on time is used to charge the inductor current back to zero before energy can begin to flow back into the output of the converter. A correction circuit is provided which extends the on time as a function of the input and output voltage to avoid dead time around the zero voltage crossover of the sinusoidal input voltage which when rectified provides the input voltage to the converter.

Growing community of inventors

Endicott, NY, United States of America

James O Groves, Jr