Abstract: In one embodiment, a high voltage element is formed overlying a doped semiconductor region that can be depleted during the operation of the high voltage element.

Abstract: A power control system (25) uses two separate currents to control a startup operation of the power control system (25). The two currents are shunted to ground to inhibit operation of the power control system (25) and one of the two currents is disabled to minimize power dissipation. The two independently controlled currents are generated by a multiple output current high voltage device (12) responsively to two separate control signals (23,24).

Abstract: In one embodiment, a start-up controller for a PWM power supply controller is formed to generate a current that is substantially constant for changes in temperature and for changes in an output voltage received by the start-up controller.

Abstract: In one embodiment, a battery charger is configured to provide a normal charge current during a first time period and to supply a maintenance current after the first time period expires.

Abstract: A power controller forms drive pulses that reduces audible noise under light load conditions.

Abstract: In one embodiment, a high voltage element is formed overlying a doped semiconductor region that can be depleted during the operation of the high voltage element.

Abstract: A power control system (25) uses two separate currents to control a startup operation of the power control system (25). The two currents are shunted to ground to inhibit operation of the power control system (25) and one of the two currents is disabled to minimize power dissipation. The two independently controlled currents are generated by a multiple output current high voltage device (12) responsively to two separate control signals (23,24).

Abstract: Disclosed herein is a fluid control system for varying the power available to a fluid powered tool, a hydraulically driven impact wrench. The system disclosed herein varies power available to the tool by use of a bypass mechanism that is downstream of a directional control valve spool. Among other things, the advantageous placement of the bypass valve limits the thermal burden in the hydraulic circuit.

Abstract: A power control system (25) uses two separate currents to control a startup operation of the power control system (25). The two currents are shunted to ground to inhibit operation of the power control system (25) and one of the two currents is disabled to minimize power dissipation. The two independently controlled currents are generated by a multiple output current high voltage device (12) responsively to two separate control signals (23, 24).

Abstract: A power control system uses two separate currents to control a startup operation of the power control system. One of the currents has a small value and is used to charge an output voltage to an initial value. Once the initial value is reached, a second current that has a large value is used to charge the output voltage to an operating voltage value.

Abstract: A differential transistor (10, 25) includes a depletion mode transistor (15,30) that has a source connected to a source of an enhancement mode transistor (11,26). The gates of the depletion mode and enhancement mode transistors are driven differentially.

Abstract: Disclosed herein is a fluid control system for varying the power available to a fluid powered tool, such as a hydraulically driven impact wrench. The system disclosed herein varies power available to the tool by use of a bypass mechanism that is downstream of a directional control valve spool. Among other things, the advantageous placement of the bypass valve limits the thermal burden in the hydraulic circuit.

Abstract: An embodiment of the present invention is a switching power supply that includes a power switching device and a control circuit to control the power switching device. Under normal operational conditions the power required by the power switching device is provided by an auxiliary secondary winding of the transformer of the power supply. When the temperature sensitive device gets into an unallowed operational condition this is no longer possible and as a consequence the device is disabled for a period of time which is determined by the amount of overheating of the device.

Abstract: A switched mode power supply has a transformer and a power switch to switch a primary current for operation in a critical conduction mode. The switched mode power supply has a controller which switches off a primary current when a peak current is reached. The primary current is switched on again when a zero current condition in the secondary is detected the first time after the primary current has been switched off and a minimum primary current off time has been reached.