Compaq Computer Corporation, Inc.

Hewlett-packard Development Company, L.p.

Compaq Information Technologies Group, L.p.

Barry N Carroll

Lee Warren Atkinson

Lee Atkinson

Thomas P Sawyers

Jean H Ho

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

Power delivery systems and methods

A power management system comprises a electronic device couplable to a power adapter. The electronic device is adapted to determine a power rating of the power adapter via an identifier associated with the power adapter and adjust at least one power-consuming activity of the electronic device based on the determined power rating.

Power management system and method

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.

System and method for power management when an operating voltage is between two thresholds

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. The rectifier further comprises a diode coupled to each of the two secondary coils to allow only positive current flow through the secondary coils. The rectifier further comprises a capacitor coupled in parallel with the control terminal of the pull-down transistor which delays switching of the rectifying transistor, thereby permitting zero voltage switching of the rectifying transistor. The rectifier further comprises a hold-down transistor configured to ground the control terminal of the pull-down transistor, thereby holding the pull-down transistor off, when the rectifying transistor is on. Zener diodes are placed in parallel with the control terminals of the pull-down and rectifying transistors to regulate voltage and prevent damage to the transistors.

AC adapter with current driven, zero-voltage switched synchronous rectifier

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.

AC adapter with automatically optimized output voltage and power

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. By changing the frequency and duration for which the transformer switch selectively connects or disconnects the primary side of the transformer, the charging circuit will have sufficient charge to power the energy demanding components when the power switch is in the first position, sufficient charge to power the switching system when the power switch is in the second position, but insufficient charge to operate the energy demanding components when the power switch is in the second position.

Isolated power supply having power switch on secondary side

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. By changing the frequency and duration for which the transformer switch selectively connects or disconnects the primary side of the transformer, the charging circuit will have sufficient charge to power energy demanding components coupled to the output line when no short circuit has been detected and sufficient charge to power the optical switch so that the power switch may be used to reset the power supply but insufficient power to operate the energy demanding components when a short circuit has been detected.

Personal computer power supply with low-power standby mode activated by

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.

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The Woodlands, TX, United States of America

Barry N Carroll