Osram Sylvania Inc.

Jinsheng Wei

Nitin Kumar

Andrew Johnsen

Ranjit Jayabalan

An active damping circuit is disclosed, which includes a peak current limiter, a drain source voltage limiter, a turn-on driver, a resistor shunt circuit, and a peak current sensor. The peak current sensor detects a rising edge of an input voltage from a phase cut dimmer by detecting a higher peak current. This drives a collector voltage of a second transistor of the peak current limiter low, which lowers a gate voltage of a first transistor of the peak current sensor, and forces it into a linear operating region, so it functions as a damping resistor. When the peak current sensor detects a decreased peak current, such that the turn-on edge of the input voltage is passed, the second transistor turns off, and the turn-on driver turns the first transistor on, such that the active damping circuit is waiting for a next edge of the input voltage.

Active damping circuit

An active damping circuit and system including the same are disclosed. The active damping circuit includes a first resistor, a second resistor, a third resistor, a first transistor, a second transistor, a capacitor, and a microcontroller. The first resistor is connected to a base of the first transistor, and to the microcontroller output. The second resistor is connected to a positive voltage, and to a collector of the first transistor and a gate of the second transistor. The third resistor is connected to a logic ground, and to a source of the second transistor. The capacitor is connected to the collector of the first transistor, the second resistor, and the gate of the second transistor. A drain of the second transistor, and the first capacitor, and the second capacitor, and the microcontroller output, are also connected to the logic ground. An emitter of the first transistor is connected to ground.

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Brea, CA, United States of America

Jinsheng Wei