Abstract: A circuit according to the present invention is used for driving a photoflash diode and comprises a current sink, a feedback circuit, and a DC-DC converter. The current sink is coupled to the photoflash diode for controlling the current through the photoflash diode. The feedback circuit receives a feedback signal indicative of the electrical condition of said first current regulator. The DC-DC converter is coupled to an external power source and the feedback circuit for powering the photoflash diode so as to control the electrical condition of the current sink to a predetermined value.

Abstract: A circuit is used for driving a plurality of LEDs by an external voltage source. The LEDs are coupled in series. The circuit comprises a plurality of switches coupled to the LEDs in parallel, respectively, for individually controlling the brightness of the LEDs. The circuit further includes a plurality of Pulse-Width Modulation (PWM) signals coupled to the switches, respectively, for individually controlling the switches.

Abstract: A computer capable of playing real time applications includes a processing circuit configured to operate in a first power state, a second power state, and a third power state where the processing circuit consumes less power in the second state than in the first state, and less power in the third state than in the second state; and a real time subsystem coupled to the processing circuit, wherein the real time subsystem includes a buffer. The buffer is further configured to store data and output the data to an output device thereby enabling the processing circuit to enter the third power state while the buffer is outputting said data.

Abstract: A smart card virtual hub combines an ISO7816 compliant smart card reader interface with a USB hub that provides one or more attachment points for connection of devices to the USB bus, thereby interfacing such devices to the host computer. The hub in the presently preferred embodiment of the invention provides one port to which one USB functional device, such as a keyboard, may be attached. The attached keyboard shares a common USB bus bandwidth with the internal embedded smart card reader through a host-scheduled, token-based communication protocol that is handled by the USB driver and the device driver.

Abstract: A method according to one embodiment may include supplying power to plurality of External Electrode Fluorescent Lamps (EEFLs). The method of this embodiment may also include generating signals proportional to the voltage of each EEFL. The method of this embodiment may also include generating a feedback signal indicative of the state of one or more of the plurality of EEFLs based on, at least in part, the value of at least one signal proportional to the voltage of each EEFL. Of course, many alternatives, variations, and modifications are possible without departing from this embodiment.

Abstract: A DC to DC controller for controlling an inrush current from a DC to DC converter to a battery system having an internal isolating switch. The DC to DC controller is configured to control the DC to DC converter based on a state of the internal isolating switch. If the switch is open, the DC to DC controller adjusts the output voltage of the DC to DC converter to a predetermined voltage level. Based on the value of such voltage level, in rush current from the DC to DC converter to the battery system can be reduced or eliminated when the isolating switch changes from an open state to a closed state. An electronic device including such a DC to DC controller is provided. Related methods for controlling inrush current are also provided.

Abstract: An analog to digital converter may include an input switch array configured to alternately sample a first and a second input signal to a first and a second input capacitor during two different sample time intervals, an integrator having a first and second integration capacitor, and a cross switch array coupled to the input switch array and the integrator. The cross switch array may be configured to alternately transfer charges from the first and second input capacitors to the first and second integration capacitors during two different transfer time intervals. A system including an analog to digital converter consistent with an embodiment and an associated method of sampling and transferring charges in an analog to digital converter are also provided.

Abstract: A cardbus controller is provided that reduces signal count and board area. In one exemplary embodiment, the controller is adapted to multiplex selected signals in a two PC Card system so that signal lines are not repeated. The selected signals may include common signals between two PC Cards. The controller may also include early detection circuitry, arbitration circuitry and power management circuitry to more effectively operate two PC Cards. In other exemplary embodiments, the invention provides a method of reducing the chip area of a PC Card controller integrated circuit by mapping an internal IDSEL signal to an external address line.

Abstract: An inverter controller for an LCD panel display with automatic brightness adjustment circuitry is provided. In one exemplary embodiment, the controller includes a look-up table that receives a signal indicative of the ambient light around the LCD panel and generates a signal corresponding to desired panel brightness. The signal corresponding to the desired panel brightness is, in turn, used as a threshold signal in a conventional feedback inverter topology supplying power to lamps associated with the LCD panel. In another exemplary embodiment, a master controller is provided that includes a light sensor controller to poll a slave light sensor to generate a signal indicative of the ambient light around the LCD panel.

Abstract: The present invention provides an integrated LCD panel power supply formed on a single printed circuit board. The integrated power supply includes at least one DC/AC control unit, at least one DC/DC buck converter unit and at least one DC/DC boost control unit. Each unit supplies power to an associated function of said LCD. The integrated power supply may also include an oscillator circuit generating a clock signal, and the clock signal is supplied to each unit thereby synchronizing the operation of each unit. The single PCB approach of the present invention eliminates the need for additional wiring between printed circuit boards and thereby eliminates or substantially reduces noise issues associated with such wiring.

Abstract: A battery charging circuit is disclosed that includes protection circuitry and/or adapter current limit offset circuitry. The protection circuitry is operable to reduce or eliminate an overvoltage and overcurrent condition generated by a charge controller when a charging path is an open circuit, for example, when a battery is disconnected from the charging path. The adapter current limit offset circuitry is operable to generate an offset signal to an adapter current signal utilized by a charger controller.

Abstract: A smart card virtual hub combines a ISO7816 compliant smart card reader interface with a USB hub that provides one or more attachment points for connection of devices to the USB bus, thereby interfacing such devices to the host computer. The hub in the presently preferred embodiment of the invention provides one port to which one USB functional device, such as a keyboard, may be attached. The attached keyboard shares a common USB bus bandwidth with the internal embedded smart card reader through a host-scheduled, token-based communication protocol that is handled by the USB driver and the device driver.

Abstract: An enabling circuit including a comparison circuit, a switching circuit, and an output decision circuit. The comparison circuit compares a first comparison signal representative of a charge on a capacitor of a DC to DC converter with a second comparison signal representative of a reference charge and provides a comparison output signal in response to the comparison. In response to the comparison output signal, the switching circuit provides a first switching signal in a first state if the charge on the capacitor is less than said reference charge. Finally, the output decision circuit accepts at least the first switching signal and provides an enabling signal to enable the DC to DC converter to be controlled by a control signal in response to the first switching signal in the first state.

Abstract: Systems are provided for the offloading of protocol control and conversion information within microprocessor-based systems. A converter controller comprises a first interface and protocol, as well as a second interface and protocol. An intermediate protocol and interface is interconnected to both the first protocol and the second protocol, and forwards or offloads protocol information to the system CPU, which comprises device driver information for protocol conversion and/or control. The CPU acts upon the received protocol information, performs protocol conversion as necessary, and forwards the converted protocol information back to the converter controller through the intermediate interface. Some embodiments of the offloading protocol conversion system comprise a SDIO controller within a USB-based device.

Abstract: A power supply system is provided for a multiple lamp LCD panel. In one aspect, the power supply includes a plurality of transformers for driving a plurality of respective CCFLs. The primary sides of each transformer are coupled in series to thereby reduce the stress on each transformer. For LCD panels that include longer CCFLs, a power supply is provided that includes a plurality of transformers for driving a plurality of respective CCFLs. The primary sides of each transformer are coupled in series and each lamp is coupled to two secondary sides of the transformers, thereby reducing the problems associated with longer CCFL tubes. In any of the embodiments, the power supply can be adapted to convert a high voltage DC signal to high voltage AC used to power the lamps.

Abstract: An adaptive LCD power supply circuit for adjusting at least one supply parameter in response to at least one load parameter of an associated load includes a feedback path configured to sense at least one load parameter and provide a control signal representative of at least one load parameter, and a regulating circuit configured to accept the control signal and regulate at least one supply parameter based on the control signal. The feedback path may include a first path to provide a first signal representative of a load condition of a first module, and a second path to provide a second signal representative of a load condition of a second load module, and a minimum decision circuit to output a third signal equal to the lesser of the first and second signals. An electronic device including an adaptive LCD power supply circuit is also provided.

Abstract: A multistage amplifier includes a first gain stage having a first input terminal and a first output terminal, and a second gain stage having a first input terminal. A first inter-stage resistive element is coupled in series to the first output terminal of the first gain stage and the first input terminal of the second gain stage to reduce the adverse affects of one gain stage on a previous gain stage. The multistage amplifier may also have a differential pair with a local feedback path for each transistor of the differential pair. Such local feedback helps to stabilize an imaginary component of the input impedance of the differential amplifier. Such stabilization also helps to reduce the adverse affects one gain stage may have on a previous gain stage.

Abstract: A compensating circuit for providing a compensating control signal to a regulating circuit is provided. The compensating circuit includes a multiplying circuit and a miller capacitor. The multiplying circuit may provide a predetermined multiplication factor to a miller current level based on a resistor ratio. The multiplying circuit may also provide a voltage gain stage before the miller capacitor. Both multiplying circuits enable the size of the miller capacitor to be reduced resulting in valuable printed circuit board space savings.

Abstract: A DC to DC converter having improved transient response, accuracy, and stability. The DC to DC converter includes a first comparator configured to compare a first signal with a second signal. The first signal has a DC offset determined, at least in part, by a DC reference voltage source. The second signal is representative of an output voltage level of the DC to DC converter. The comparator is further configured to provide a control signal to a driver based on a difference between the first signal and the second signal, the driver driving the output voltage of the DC to DC converter. The DC to DC converter further includes an accuracy circuit to enhance accuracy of the DC to DC converter. The DC to DC converter may further include a stability circuit to enhance stability of the DC to DC converter.

Abstract: A CCFL power converter circuit is provided using a high-efficiency zero-voltage-switching technique that eliminates switching losses associated with the power MOSFETs. An optimal sweeping-frequency technique is used in the CCFL ignition by accounting for the parasitic capacitance in the resonant tank circuit. Additionally, the circuit is self-learning and is adapted to determine the optimum operating frequency for the circuit with a given load. An over-voltage protection circuit can also be provided to ensure that the circuit components are protected in the case of open-lamp condition.