Abstract: A high-voltage DC floating system includes a source, a power rail, a power bus, a load, and a pre-charge circuit. The power bus includes a positive bus portion and a negative bus portion. The pre-charge circuit includes a first pre-charge circuit portion that is configured to equalize a voltage across the positive power supply switch between the source and a Y-capacitance of the load and a second pre-charge circuit portion that defines a switched path to ground that is configured to equalize a voltage associated with a Y-capacitance of the negative power rail.

Abstract: A brushless AC servo motor control and modified motor to minimize the rotational acceleration and deceleration of a semiconductor wafer during processing steps where fluid is applied in a thin coating on the wafer. The control utilizes sine and cosine encoder outputs of single cycle and multiple cycle per revolution to calculate motor shaft position by an inverse tangent calculation of sine and cosine ratios. Resolution of motor shaft position is greatly improved as is rotational velocity control. In response to a prediction of desired shaft position in comparison with actual position the three field currents are adjusted to change the torque applied to the rotor and shaft. In the semiconductor wafer manufacturing application the motor shaft is modified to permit vacuum attachment of the wafer to the disc that rotates with the shaft.