Abstract: Systems, methods, and devices which estimate the inductor current in a power factor correction (PFC) converter for use with AC/DC converters. A control system for use with the PFC takes as input the input voltage and the output voltage of the PFC. Control signals for power semiconductor subcircuits in the PFC are then output from the control system. The control system uses an adaptive observer sub-circuit that estimates the inductor current and the bus voltage. The adaptive observer uses an adaptive updater which uses both the estimates and the estimate error to update the adaptive observer's estimates.

Abstract: A control approach of adjusting the input power of a power factor correction (PFC) stage so that the output voltage (DC-link) of the input AC/DC stage to an intermediate DC voltage (DC-Bus voltage) is adjusted based on the amount of power required to charge a high energy battery is disclosed. The present invention controls the input power of the PFC instead of the DC-bus voltage as is common in conventional methods. Therefore, a very fast response compared to the conventional sluggish voltage loop can be achieved. Also, having different DC-bus voltages for different output load conditions allows the DC/DC converter to work with an optimal duty cycle for a whole range of load variations.

Abstract: Provided are circuits and methods for a digital controller for an electronic ballast for a fluorescent lamp, comprising a feed-forward loop that provides information about a voltage firing angle, and a pulse width modulator that controls a duty ratio of at least one power switch of the electronic ballast according to the information. The digital controller may include a duty ratio controller implemented in the pulse width modulator. The digital controller may include one or more functions such as dimming, maintaining high power factor throughout the dimming range, low lamp power detection, lamp soft-start, and DC-link capacitor over-voltage detection for end of life protection or lamp failure protection. In one embodiment the ballast is a single stage, single switch ballast.