International Business Machines Corporation

Ericsson Gmbh

Nicholas Celenza

Brian Christopher Totten

Jamaica LaQuay Barnette

Ismael Orozco Biaggi

Raymond Mathew Clemo

Elie M Najm

Brian David Miller

Ronald S Jungling

A method of controlling the inrush current to a hot plug device. The method includes directing current from an input power rail of the hot plug device to an output power rail of the hot plug device through a high impedance auxiliary current path, wherein an electronic subsystem of the hot plug device is coupled to the output power rail. The method further includes allowing current from the input power rail to pass through a plurality of main turn on FETs to the output power rail in response to the output power rail having a voltage that exceeds a voltage threshold as a result of directing current through the high impedance auxiliary current path.

Hot plug device providing turn on FETs with a softstart capability

A hot plug device includes an electronic subsystem and a plurality of main turn on FETs, wherein each main turn on FET includes a gate, a power input for coupling to a power source, and an output for controllably providing power to the electronic subsystem. An auxiliary current path is in parallel with the main turn on FETs and includes a fuse, an impedance element and an auxiliary turn on FET. A turn on controller controls the main turn on FETs and the auxiliary turn on FET. Current is initially through the high impedance auxiliary current path to apply voltage to an output power rail. Subsequently, current is allowed to pass through a plurality of main turn on FETs to the output power rail in response to the output power rail having a voltage exceeding a voltage threshold as a result of using the high impedance auxiliary current path.

A method for controlling the in-rush current to a hot plug device. The method includes providing a series of turn on pulses to the gates of a plurality of turn on FETs on a hot plug device coupled to a direct current power source, wherein each pulse causes the plurality of FETs to pass current from the direct current power source to a subsystem of the hot plug device, and wherein each pulse has a duration that ends before the impedance of the turn on FETs falls below a safe operating region. The method further includes providing a steady turn on signal to the FETs in response to the output voltage from the FETs to a subsystem of the hot plug device exceeding a predetermined voltage threshold.

Controlling turn on FETs of a hot plug device

A computer program product for controlling the in rush current to a hot plug device. The computer program product includes program instructions that cause a processor to perform a method. The method includes providing a series of turn on pulses to the gates of a plurality of turn on FETs on a hot plug device coupled to a direct current power source, wherein each pulse causes the plurality of FETs to pass current from the direct current power source to a subsystem of the hot plug device, and wherein each pulse has a duration that ends before the impedance of the turn on FETs falls below a safe operating region. The method further includes providing a steady turn on signal to the FETs in response to the output voltage from the FETs to a subsystem of the hot plug device exceeding a predetermined voltage threshold.

Administering offset voltage error in a current sensing circuit including recording by a power supply management module a current sensing voltage for a power supply when no operating load is drawn from the power supply and dynamically calculating by the power supply management module output current of the power supply with an active load in dependence upon the recorded current sensing voltage.

Administering offset voltage error in a current sensing circuit

A battery charger to recharge a battery comprises a transistor switch coupled with a cable loss compensator. Additionally, the battery charger includes a comparator, a current limiter, and a differential amplifier. The circuits are created from discrete components, and particularly include individual transistors. A smoothing network takes the signal from the switch and passes it along to the battery for recharging.

Transistor driven wall charger

An apparatus which connects/disconnects battery from a load such as a computer system includes a first circuit arrangement which sets a first reference voltage level at which the energy source is connected through an FET device to the computer system, a second circuit arrangement that sets a second voltage level at which the energy source is disconnected by the FET device from the computer system and a third circuit arrangement which controls the FET device so that said FET device is forced into either its ON or OFF state once one of the reference voltages is reached. A second apparatus which reduces power dissipation in a battery charger power device by forcing the input voltage to track the battery voltage as the battery charges/discharges.

Voltage sensitive switch

Described is a novel power supply for generating a constant d.c. voltage from a variable a.c. voltage supply line. The power supply includes a plurality of switch circuits which monitor voltage levels on respective secondary windings of a power transformer and as voltage levels change, one of the plurality of switch circuits is selected to charge a capacitor which provides a range of d.c. voltages which are processed to provide the constant d.c. voltage.

Growing community of inventors

Durham, NC, United States of America

Nicholas Celenza