Picor Corporation

Andreas Gerasimos Ladas

Aiman Alhoussami

John P Clarkin

Claudio Tuozzolo

Robert M Lanoue

An apparatus and method for protecting a switch from overvoltage transients that might otherwise occur when the switch is turned off. A transient-suppression controller controls a rate-of-change of voltage across a switch by delivering control signals to the switch. Controlling the rate-of-change of voltage enables controlled absorption of stored parasitic energy that might otherwise cause overvoltage transients. In some embodiments the switch is a MOSFET and the control signals are currents delivered to the gate of the MOSFET. In some embodiments, control is open-loop; in other embodiments closed-loop control is used to maintain essentially constant voltage across the switch as it turns off.

Suppressing electrical bus transients in electronic circuitry

In some implementations, a method of dynamically maintaining a device's operation within a safe operating area (SOA) may include sensing instantaneous voltage and current of the device; determining, based on the sensed instantaneous voltage and current, a value that represents a power dissipated in the device; using the determined dissipated power and a model of thermal behavior of the device to model a junction temperature of the device; and controlling operation of the device based on the modeled junction temperature. A programmable SOA circuit including sensing, scaling, filtering, and controlling functions may be packaged on a single die or in a package with a power transistor.

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Kingston, RI, United States of America

Andreas Gerasimos Ladas