International Business Machines Corporation

Girish Chandra Johari

Brian Ashley Carpenter

Peter Matthew Thomsen

Mark Wayne Mueller

Lucinda Mae Walter

Darryl C Newell

Terry Brooks

Kevin M Silk

A method of servicing a computer system without interrupting operation of the computer system, by connecting a computer component to a board of the computer system, detecting connection of the computer component to the system board using a control circuit, supplying power to the voltage input of the computer component in response to detecting the connection, and thereafter monitoring the power supplied to the voltage input of the computer component. The method may be used for core computer components such as CPU modules and voltage regulator modules. Power to the voltage input of the computer component is turned off in response to a determination that a current level of the power supplied to the voltage input exceeds a specified level. A fault signal is latched in an active state in response to the determination; the fault signal is reset when the component is removed from the system. The method also applies to a plurality of hot-pluggable components, wherein the power supplied to each component is individually monitored.

Hot plug control of MP based computer system

A power subsystem for a computer system allows a voltage regulator module (VRM) to be removably connected to a system board, while limiting disturbances on the voltage rails of the system board. The electrical disturbances are prevented by charging voltage outputs of the DC/DC circuit of the VRM prior to directly connecting the voltage outputs to the voltage rails. To ensure that the voltage outputs are properly charged, a VRM connector may be used in which the voltage output pins are shorter than charge pins which are coupled to respective capacitors and to the voltage outputs of the DC/DC circuit. In this manner, as the connector is mated with a corresponding connector on the system board, the capacitors are first charged via resistive paths connected to the voltage rails, prior to directly connecting the voltage outputs to the voltage rails. The VRMs are thus &ldquo;hot-pluggable,&rdquo; enabling a user to upgrade or service the system with no interruption.

Hot-pluggable voltage regulator module

A modular DC power distribution system. A physically discrete input conversion module is utilized for converting a source AC signal to a high voltage DC signal. Multiple universal mounting sites are provided in a power supply backplane for engaging one or more of such input conversion modules. Within the power supply backplane, the high voltage DC signal is delivered to a DC distribution bus. A physically discrete DC step-down module is utilized for converting the high voltage DC signal from the DC distribution bus to a point-of-load DC signal distributable to application boards. The power supply backplane includes multiple universal mounting sites wherein one or more DC step-down modules may be installed or removed. In another embodiment, the DC power distribution system of the present invention includes a pre-charge system for permitting the input conversion modules and the DC step-down modules to be hot plugged into the power supply backplane.

Modular DC distribution system for providing flexible power conversion scalability within a power backplane between an AC source and low voltage DC outputs

Aspects for sensing faults in a redundant power converter are described. An exemplary circuit aspect includes a signal transition monitor for monitoring signal transitions at a predetermined node within the redundant power converter, and a detector for detecting a fault condition in the redundant power converter when a proper signal transition fails to occur during a base period of switching. The aspects sense faults in a manner which allows replacement during a scheduled downtime, so that redundancy is restorable without having an unscheduled outage.

Fault detection in a redundant power converter

Aspects for reporting faults in a redundant power converter are described. An exemplary method aspect includes monitoring at least one node within the redundant power converter. The method further includes tracking values of the at least one node during a predetermined time period, and predicting when a specification of the redundant power converter will be exceeded based on the tracked values.

Fault reporting in a redundant power converter

Aspects for isolating faults in a redundant power converter are described. An exemplary system aspect includes a first switch at an input of the redundant power converter for protecting the redundant power converter from a high input voltage, and a second switch coupled within the redundant power converter prior to an output capacitor, wherein efficiency of fault isolation is improved.

Fault isolation in a redundant power converter

A synchronous converter including a control module including a pulse generator configured to produce a pulse. An input port suitable for receiving an input voltage from a voltage source, is couple to a first conversion stage of the converter. The first conversion stage preferably includes a first pair of transistors, a first stage capacitor, and a first winding of a coupled inductor. The first pair of transistors are preferably driven by the control module pulse generator such that the first conversion stage is coupled to the input port during the first interval of the pulse and isolated from the input port during the second interval of the pulse and the gain of the first conversion stage is approximately equal to the duty cycle of the pulse. The converter further includes a second conversion stage preferably including a second pair of transistors, a second stage capacitor, and a second winding of the coupled inductor. The second pair of transistors are preferably driven by the control module pulse generator such that the second conversion stage is coupled to the first conversion stage output during the first interval and isolated from the first conversion stage during the second interval. The gain of the second conversion stage, like the first stage, is approximately equal to the duty cycle of the pulse generator. The first and second conversion stages are coupled by the common inductive core of the coupled inductor.

Synchronous voltage converter

A system and method for measuring the load current in a power supply driven by switched transformer or the like. Rectified rectangular waveform input voltage pulses are interrupted to exhibit a less than 100 percent duty cycle with an off state value approaching zero volts. A filtering inductor is situated in normal manner between the input voltage pulses and the load. Preferably, a capacitor is connected across the load. A freewheeling diode and sensing resistor are connected across the less than 100 percent duty cycle rectangular input voltage. The peak values of the current pulses through the sensing resistor have been determined to be related to the load current of the power supply. The voltage drop across the resistor is amplified, detected and used to regulate the magnitude of the limited duty cycle input voltage. The voltage drop across the resistor may be used to limit the power supply output current or to balance current in parallel configurations of multiple power supplies. The placement of the sensing resistor in the path of the freewheeling diode allows load current measurement with minimum power dissipation.

Low dissipation current sensing system for a switched DC power supply

A constant loop gain is achieved in a flyback type DC to DC converter by use of feedback to correct for load variations and feed forward to correct for line voltage variations. The feedback signal and a reference voltage are compared by an error amplifier. An output of the error amplifier is multiplied by a constant and is added to a signal proportional to line voltage. The resulting sum causes modification of the slope of a ramp voltage which is compared to the voltage at the output of the error amplifier to control the 'on' times of the converter switching devices.

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Austin, TX, United States of America

Girish Chandra Johari