Abstract: A comparison circuit for comparing the desired voltage levels of electronic components and for disabling the supply of power to those components if the desired voltage levels are not equivalent. The comparison circuit receives the desired voltage level indication signals and provides a signal indicating whether the desired voltage levels are equivalent. If the desired voltage levels are not equivalent, the comparison circuit provides a signal indicating non equivalency to a power supply, wherein the power supply is disabled from supplying power so as not to damage the computer components from receiving power at a non allowable voltage level. The comparison circuit also provides an output signal indicative of an equivalent voltage level to the desired voltage levels if the desired voltage levels are equivalent. A power supply converter supplies power to the components at a voltage level as indicated by the output signal.

Abstract: A restart circuit for a power supply of an electronic system such as a computer system for delaying the restart of the power supply until a power supply output is in compliance with a specified parameter. In one embodiment, the specified parameter is a particular threshold voltage level and the power supply output is in compliance when it is less than the particular threshold voltage level. In another embodiment of a restart circuit, the specified parameter is a rate of decay in a voltage level and the power supply output is in compliance when it is decaying at a rate less than the predetermined rate. In one embodiment, delaying the restart of the power supply permits components of the system to be reset when the voltage level of the power supply output is in a known state.

Abstract: A comparison circuit for comparing the desired voltage levels of electronic components and for disabling the supply of power to those components if the desired voltage levels are not equivalent. The comparison circuit receives the desired voltage level indication signals and provides a signal indicating whether the desired voltage levels are equivalent. If the desired voltage levels are not equivalent, the comparison circuit provides a signal indicating non equivalency to a power supply, wherein the power supply is disabled from supplying power so as not to damage the computer components from receiving power at a non allowable voltage level. The comparison circuit also provides an output signal indicative of an equivalent voltage level to the desired voltage levels if the desired voltage levels are equivalent. A power supply converter supplies power to the components at a voltage level as indicated by the output signal.

Abstract: A comparison circuit for comparing the desired voltage levels of electronic components and for disabling the supply of power to those components if the desired voltage levels are not equivalent. The comparison circuit receives the desired voltage level indication signals and provides a signal indicating whether the desired voltage levels are equivalent. If the desired voltage levels are not equivalent, the comparison circuit provides a signal indicating non equivalency to a power supply, wherein the power supply is disabled from supplying power so as not to damage the computer components from receiving power at a non allowable voltage level. The comparison circuit also provides an output signal indicative of an equivalent voltage level to the desired voltage levels if the desired voltage levels are equivalent. A power supply converter supplies power to the components at a voltage level as indicated by the output signal.

Abstract: A switching voltage regulator and a method of providing transition control therein. The regulator includes: (1) a modulation circuit for generating switching signals, (2) first and second switches coupled between a regulator output of the voltage regulator and respective first and second voltage inputs, control inputs of the switches coupled to the modulation circuit to allow the switches to couple the regulator output alternately between the voltage inputs as a function of a state of the switching signals and (3) a regulator output power waveform transition control circuit coupled to the control inputs of the switches for generating an override signal to the control inputs under a specified condition, the override signal causing the switches to couple the regulator output to the first voltage input independent of the state of the switching signals.

Abstract: By separating a power regulator at a point between the output inductor and the output capacitor of the regulator, the capacitive output section can be located close to a processor (or other load device) while the remaining portion of the regulator can be placed in another location away from the processor. With the capacitive output section located close to the processor and valuable system board space can be saved.

Abstract: A personal computer includes a DC to DC converter which employs a dual function capacitive energy storage device at the output rail of the converter. The energy storage device provides both a transition control function and a bulk or output function. In this manner, the size and expense of a separate bulk capacitor is advantageously avoided. The converter includes a switching transistor coupled to a bulk inductor. The switching transistor exhibits a high frequency switching rate which is sufficiently high to permit the inductor to directly replenish the capacitive energy storage device thus enabling the converter to withstand both major and minor load fluctuations without loss of voltage regulation at the output rail.

Abstract: A discharge control circuit for a power supply switching converter that, in response to a cessation of current from an AC power source, makes conductive a main switching element of the switching converter to discharge the bulk filter capacitor through the main switching element to a charge level that meets safety standards. The discharge control unit includes a current limiting circuit for limiting the discharge current through the main switching element in which the rate of rise of the discharge current is controlled with the use of an RC circuit. The discharge control unit also includes a state machine that activates the current limiting circuit in response to a cessation of the modulation mode of the switching converter. The discharge control circuit also includes a reset circuit for placing the state machine in a known state during the startup of the switching converter.

Abstract: Electronic systems such as computer systems often utilize regulated voltage to meet system requirements such as accurate logic levels and predictable performance. A switching voltage regulator implements a pulse width modulator using two timer circuits, such as 555 class timers, configured in a master/slave relationship to provide modulation signals to control current flow to a voltage regulator output filter. The switching regulator employing the pulse width modulator may be arranged as a buck switching voltage regulator, and the pulse width modulator alternately turns switches in a switch bank ON (low impedance current path) and OFF (high impedance current path) to facilitate current flow to energy storage elements configured as an averaging filter. Furthermore, additional timer circuitry may be implemented to ensure nonoverlap of current flow in the switches.

Abstract: A multiphase direct current (DC) regulator using voltage mode control to provide a regulated voltage and provide current equalization between the phases. The regulator includes a voltage mode control circuit receiving an indication voltage level indicative of the amount of current supplied from the DC power source to an inductor of a first phase. The voltage mode control circuit providing a first control signal dependent upon the indication voltage level to a switching circuit that provides a switching signal to a switch. The switch controlling the amount of current from the DC power source supplied to a second inductor of a second phase according to the switching signal.

Abstract: A power supply includes a power factor correction converter and a controller that disables a power factor correction converter when the power supply is operating in a low power mode, when the power factor correction converter is not needed. The controller of the power factor correction converter performs control operations as directed by a control program executing in a computer or processor in some embodiments. In other embodiments, the control operations are directed by an automatic sequence self-directed by a state machine or other sequencer according to a self-analysis.

Abstract: Method and apparatus for providing a regulated, direct current (DC) output voltage for use in computers. An unregulated voltage source is regulated by a power converter of the present invention that produces the regulated voltage reliably, inexpensively, and without requiring heat sinks or auxiliary fans. In a preferred embodiment, the power converter includes a buck regulator and a control circuit. The control circuit includes a resistor-divider feedback loop connected to the output of the buck regulator in order to provide a feedback voltage. The feedback voltage is supplied to an error amplifier which compares the feedback voltage to an internal reference voltage and produces an output that is the amplified difference between the two voltages. The amplified output is then provided to a frequency modulation (FM) port of a multipurpose timer. As a result, the timer can control and modulate the frequency and pulse width of the buck regulator.

Abstract: A circuit for determining and reporting the energy consumed by an electronic device having a microprocessor and power supply lines for supplying power to the device is disclosed. The circuit comprises a voltage divider connected for sensing the voltage across the power supply lines and generating a voltage signal indicative of the sensed voltage. A current sense resistor is connected in series with a power supply line for sensing the current passing through the power supply lines and generating a current signal indicative of the sensed current. An analog multiplier is connected for receiving and computing the product of the voltage and current signals, and for generating a power signal indicative of the product of the voltage and current signals, the power signal being indicative of the power consumed by the device.

Abstract: Method and a system for automatically and securely performing computer power up and logon functions. In one embodiment, the system is implemented in a personal computer ("PC") and comprises a central processing unit ("CPU"), a card reader for reading data encoded on user identification cards "swiped" therethrough, and a power supply capable of constantly providing a low power, or "flea power," signal to various components of the PC, including the CPU and card reader, for enabling a soft power startup of the PC. Responsive to detection of a user identification card being swiped through a slot on the card reader, the card reader reads information for identifying the user, in particular, a user ID and security code, encoded on the card and transmits the read information to the CPU. If the CPU determines that the user identified by the user ID is authorized to access the PC, the PC is powered up and the user is logged onto the PC using the data read from the card.

Abstract: A surge modification circuit controls surge current flows which may occur when a computer and AC adapter are connected. The surge current flows are controlled using active circuitry since passive circuitry, which is in place continuously, sustains large uninterrupted heating power losses in the order of watts that are wasted over time. In one embodiment, a surge modification circuit in an AC adapter includes a control element that operates as a power analog switch with a slow transition time to reduce the steepness of a surge wavefront resulting from the connection of the output terminals of the AC adapter to a computer while the AC adapter is energized.

Abstract: A determinate power source control for an integrated circuit (10) includes a variable voltage regulator (16), which is operable to receive a supply voltage on the input thereof and output a regulated voltage for input to the integrated circuit (10). A voltage adjustment circuit (22) is operable to generate a voltage adjustment value V.sub.ADJ for input to the voltage regulator (16) to determine the voltage output thereby. In a determinate operating mode, the voltage adjustment circuit (22) varies the V.sub.ADJ value to cause the regulator (16) to vary the regulated output voltage to the integrated circuit (10). For each value, the operating speed of the integrated circuit (10) is determined and this information stored in a table (24). Thereafter, the voltage adjustment circuit (22) is placed in an operating mode wherein the voltage adjustment value associated with the optimum operating speeds of the integrated circuit (10) is selected and input to the voltage regulator (16).

Abstract: An integrated circuit package comprising an integrated circuit device and a voltage converter circuit both embedded within the package. The voltage converter circuit is configured to convert a standard supply voltage to an operating voltage as required by the integrated circuit device. Also, discrete embedded capacitors may be included to capacitively couple power and ground connections of the integrated circuit device and thus reduce voltage variations during operation of the integrated circuit device. The integrated circuit may package include one or more layers. One or more discrete components or integrated circuits are mounted to one or more layers within the package. Internal conductors on one or more of the layers are configured to connect the components forming the voltage converter circuit. Internal conductors also form connections to the integrated circuit device. The integrated circuit device and voltage converter circuit may be coated with an encapsulant for added protection.

Abstract: A self-shutdown system for a circuit card when removed from the connector of a primary system, where the circuit card includes a local power source for providing power when primary power is not available. A dedicated sense pin on the connector of the card is grounded to the remaining ground pins when the card is plugged in but floats or is otherwise disconnected when the card is unplugged from the primary system. A ground switch circuit connected to the sense pin and the remaining ground pins asserts a shutdown signal for disabling the circuitry on the card when the ground sense pin is floating or deasserts the shutdown signal when the ground sense pin is grounded. In one embodiment, the disable mechanism is a switch circuit for disconnecting the main circuitry of the card from the local power source. In the preferred embodiment, however, a DC/DC converter receives the shutdown signal and disables the remaining circuitry when the shutdown signal is asserted.

Abstract: A minimum fan RPM control circuit constantly turns a computer exhaust fan at a minimum RPM while the computer is on. The RPM control circuit includes a blanking and reset circuit responsive to a ramp signal, for generating a reset pulse at a reset output. The RPM control circuit also includes a latch circuit conductively coupled to the reset output, the latch circuit responsive to the reset pulse, and responsive to a tachometer pulse, for generating a latch pulse at a latch circuit output. The RPM control circuit further includes an integration node conductively coupled to the latch circuit output, and responsive to the latch pulse, for generating an integral signal of the latch pulse. Finally, the RPM control circuit includes a power switch driver conductively coupled to the integration node, and responsive to the ramp signal and the integral signal, for generating an RPM control pulse.

Abstract: A three-way power switch for turning on and off an entire computer system with a single switch. The host computer includes a soft-start circuitry for detecting display data channel (DDC) activation signals from a DDC-capable monitor. Thus, a toggle power switch on the monitor turns on and off the entire system, where the computer powers up or down based on the presence or absence, respectively, of the DDC signals. In a second embodiment, the monitor includes soft-start circuitry which detects the presence/absence of video signals from the host computer for powering up/down the monitor, respectively. Thus, in the second embodiment, a power switch either on the monitor or computer system is used to turn on and off the entire system. A third embodiment is similar to the second embodiment except bi-directional DDC2 signals are used as an activation signal to power up or down the monitor.