Abstract: Embodiments of the present invention include circuits and methods for calibrating lens displacement in a voltage controlled actuator. In one embodiment, a calibration circuit comprises a programmable voltage source that provides a voltage to a control terminal of an actuator to set a lens displacement, a switch that selectively decouples said programmable voltage source from said control terminal, a current source that provides a reference current to said control terminal when the control terminal is decoupled from said programmable voltage source, a comparator that senses a voltage difference between said programmable voltage source and said control terminal, and a timer coupled to an output of the comparator. The timer measures a time period required to increase the control terminal voltage. The capacitance of the actuator may be determined and used to calibrate the position of a lens.

Abstract: A switch state controller generating a pulse train is used in a power converter utilizing a plurality of converter stages all simultaneously controlled by a single switch controlled by said pulse train. On time of the pulse train is controlled according to an input or interim node characteristic of the supply and period is controlled by a characteristic of the output of the converter. This allows development of AC-to-DC converters, including power-factor-correction converters, and DC to DC converters with high conversion ratio with minimal parts count & high reliability.

Abstract: An apparatus and method for adaptively controlling power supplied to a hot-pluggable subsystem controls the inrush current of the hot-pluggable subsystem when the subsystem is coupled to another system that supplies power, and optionally other signal connections. The apparatus and method adaptively control a pass device by detecting the voltage at the gate of the pass device during initial charging of the gate. The gate voltage may be sampled and used subsequently to control the operation of the pass device, and short-circuit conditions may be detected by determining that the miller effect does not change the charging of the gate capacitance. Automatic restart circuitry can be included to generate multiple startup attempts, and under-voltage lockout circuitry and power-on-reset timers can be used to provide a robust solution. The apparatus and method can be adapted to provide a three terminal device that does not require a feedback connection from a power supply output.

Abstract: A switch state controller generating a pulse train is used in a power converter utilizing a plurality of converter stages all simultaneously controlled by a single switch controlled by said pulse train. On time of the pulse train is controlled according to an input or interim node characteristic of the supply and period is controlled by a characteristic of the output of the converter. This allows development of AC-to-DC converters, including power-factor-correction converters, and DC to DC converters with high conversion ratio with minimal parts count & high reliability.

Abstract: A feedback apparatus and method for adaptively controlling power supplied to a hot-pluggable subsystem controls the inrush current of the hot-pluggable subsystem upon application of power. The apparatus and method adaptively control a pass device by detecting the current through the pass device during initial charging of a load capacitance and scaling back the turn-on rate at the pass device control terminal input in conformity with the detected current and a predetermined rate set by a ramp generator. A ramp capacitor is coupled to the control terminal of the pass device through a diode to permit use of the capacitor for timing purposes as well as preventing transient turn-on of the pass device during initial application of power.

Abstract: An apparatus and method for adaptively controlling power supplied to a hot-pluggable subsystem controls the inrush current of the hot-pluggable subsystem when the subsystem is coupled to another system that supplies power, and optionally other signal connections. The apparatus and method adaptively control a pass device by detecting the voltage at the gate of the pass device during initial charging of the gate. The gate voltage may be sampled and used subsequently to control the operation of the pass device, and short-circuit conditions may be detected by determining that the miller effect does not change the charging of the gate capacitance. Automatic restart circuitry can be included to generate multiple startup attempts, and under-voltage lockout circuitry and power-on-reset timers can be used to provide a robust solution. The apparatus and method can be adapted to provide a three terminal device that does not require a feedback connection from a power supply output.