Abstract: Power delivery systems and methods are provided. A power delivery system (100) can include a thermal device (140) disposed at least partially within the external power delivery device (110). The thermal device can be configured to output a first signal (150) corresponding to an internal temperature of the power delivery device when the internal temperature of the power delivery device exceeds a predetermined threshold.

Abstract: Power delivery systems and methods are provided. A power delivery system (100) can include a thermal device (140) disposed at least partially within the external power delivery device (110). The thermal device can be configured to output a first signal (150) corresponding to an internal temperature of the power delivery device when the internal temperature of the power delivery device exceeds a predetermined threshold.

Abstract: A display system is provided, the display system having a processor and a Liquid Crystal Display (LCD) coupled to the processor. The display system also includes a backlight for the LCD panel, the backlight having an adjustable backlight luminance. The processor causes a plurality of successive image frames to be displayed on the LCD panel. The backlight luminance is selectively adjusted for each of the image frames.

Abstract: A system comprises power management logic and an electrical load coupled to the power management logic. The electrical load is configurable to operate in accordance with any of a plurality of power states. The power management logic forces the electrical load to operate in a reduced power state if an operating voltage for the system is between two thresholds.

Abstract: A rectifier comprising a current transformer configured to receive a bipolar signal. The current transformer is comprised of a primary coil and preferably two secondary coils with opposite polarities. The rectifier also includes a rectifying transistor coupled to one of the secondary coils in the current transformer. Positive current from the first secondary coil causes the transistor to turn on thereby allowing current to flow through the transistor from the input of the rectifier to the output of the rectifier. A pull-down transistor is coupled to a second secondary coil of the current transformer. Positive current from the second secondary coil causes the pull-down transistor to turn on. The pull-down transistor is configured to connect the control terminal of the rectifying transistor to ground, thereby turning the rectifying transistor off, when the pull-down transistor is turned on.

Abstract: A portable docking and precharging station with an AC adapter with automatically optimized output voltage and power. An IIC communications link between the computer and AC adapter carries signals which adjust the AC adapter's voltage and power settings, depending on the charge state of the battery and whether the computer is on or off. If the computer is on, full output power is provided from the AC adapter. If the computer is off, the output power from the AC adapter is reduced so that the current cannot exceed the battery manufacturer's recommended charging rates. Preferably the regulated output voltage and the current limit are both changed when the change between modes occurs.

Abstract: A power supply for a computer system having at least one energy demanding component. The power supply includes a transformer having a primary side coupled to an AC main and a secondary side coupled to an output line, a charging circuit coupled between the secondary side of the transformer and the output line, an optical switch coupled to the secondary side of the transformer and comprised of an optical transmitter and an optical receiver, a secondary side power switch coupled to the optical receiver, a pulse width modulator coupled to an output of the optical receiver and a transformer switch coupled to an output of the pulse width modulator. The pulse width modulator generates a pulse sequence which alternates between first and second states, each having respective durations and frequencies. At each change between the first and second states, the transformer switch selectively connects or disconnects the primary side of the transformer with the input line.

Abstract: A power supply for a computer system includes a transformer having a primary side coupled to an AC main and a secondary side coupled to an output line, a charging circuit coupled between the secondary side of the transformer and the output line, an optical switch coupled to the secondary side of the transformer and comprised of an optical transmitter and an optical receiver, a secondary side power switch coupled to the optical receiver, a short circuit protection circuit coupled to the charging circuit, the output line and the optical receiver, a pulse width modulator coupled to an output of the optical receiver and a transformer switch coupled to an output of the pulse width modulator. The pulse width modulator generates a pulse sequence which alternates between first and second states, each having respective durations and frequencies. At each change between the first and second states, the transformer switch selectively connects or disconnects the primary side of the transformer with the input line.

Abstract: A capacitor connected directly across the terminals of the primary inductance of a transformer of a switched mode power supply and a separately wound inductor connected between the primary inductance and the switching power transistor which form a lossless snubber circuit. The snubber circuit is more efficient since resistors are not used to dissipate the energy as unwanted heat. The capacitor increases the transistor turn off voltage rise time, thereby reducing radiated emissions. The inductor reduces emissions appreciably by absorbing the ringing that would otherwise occur after the transistor is turned fully off and increases the transistor turn on time.