Abstract: A snubber circuit for use with an integrated power supply control circuit incorporating a transformer and a lateral power MOSFET on a single silicon chip. A capacitor is provided in circuit with the MOSFET and first resistor and diode are in series with each other and the capacitor. A second resistor and diode are also in series with each other and the capacitor. The diodes provide for first current flow in one and an opposite direction and the resistors provide first and second levels of resistance respectively for damping and turn on. In another embodiment, first and second resistors are provided in series with the capacitor, and a diode is connected across one of the resistors.
Abstract: A method and circuit for detecting the position of the movable element of an electrically commutated machine. The method and apparatus allow detection of the back electromagnetic force (BEMF) waveform with all legs of the machine energized by mathematically removing the applied voltage from the measured voltage across the phases.
Type:
Grant
Filed:
September 30, 2004
Date of Patent:
September 30, 2008
Assignee:
The Berquist Torrington Company
Inventors:
Haroon I. Yunus, Russel H. Marvin, Bumsuk Won