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: Systems are provided for the enhancement of the system BIOS for microprocessor-based devices. Before the end of a BIOS start-up procedure, the BIOS operation is diverted to a BIOS security authentication system which may be a portion of an enhanced system BIOS. The BIOS security authentication system establishes communication with an information module, if the information module is present. The information module is typically a removable or installable card, which may be unique to one or more users. Based upon an information exchange between the security authentication module and the information module, the security authentication module controllably allows or prevents the system BIOS start-up procedure to resume and finish. In a preferred embodiment, the security authentication module is used as a pre-boot authentication system, to prevent a microprocessor-based device from booting up, unless a valid authorized information module is present.

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 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 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 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.

Abstract: An analog to digital converter (ADC) includes a cross switch array coupled between an input switch array and an integrator configured to alternately transfer charges from a first input capacitor and a second input capacitor to a first integration capacitor and a second integration capacitor thereby improving linearity problems caused by capacitor mismatching. The cross switch array may also be configured to transfer charges from the first input capacitor to the first integration capacitor and from the second input capacitor to the second integration capacitor during a first charge transfer time interval, and from the first input capacitor to the second integration capacitor and from the second input capacitor to the first integration capacitor during a second charge transfer time interval. A sensing system including and ADC consistent with the invention is also provided. Various methods of transferring charges in an ADC are also provided.

Abstract: A programmable after-package, on-chip reference voltage trim circuit for an integrated circuit having a plurality of programmable trim cells generating a programmed sequence. A converter is provided to convert the bit sequence into a trim current. The trim current is added to an initial value of a reference voltage to be trimmed, as generated by the integrated circuit. Once the correct value of the trim current is determined, isolation circuitry is programmed to isolate the trim circuitry from the remainder of the IC, thereby freeing the logic and package pins associated with the IC for use by users of the IC. The preferred trim circuitry includes fuses which are blown in accordance with a bit value supplied to the trim cell to permanently fix a trim current value, once a best fit value is determined.

Abstract: A lamp driving system that includes a first impedance and a second impedance coupled to the secondary side of a transformer, where the second impedance has a phase shifted value compared to the first impedance. Two lamp loads are connected in series together, and in parallel to the first and second impedances and to the transformer. The phase shift between the impedances ensures that the transformer need not supply double the striking voltage to strike the series-connected lamps. A difference in the resistance between the first and second impedances ensures that the lamps ignite in a specified sequence.

Abstract: A power management unit (PMU) apparatus and method may include: a bi-directional pin configured to serve as an input pin during a first condition and as an output pin during a second condition; or a battery charge controller for providing a first conditioning charge and a second full charge to a voltage source of the PMU; or an adapter detector configured to detect the presence of a continuous output adapter and a pulse output adapter; an under voltage lockout protection circuit to prevent start up of the PMU until a power source reaches a predetermined threshold lockout level and to shut down the PMU once the power source reaches a lower threshold lockout disabling level; or a plurality of internal switches for allowing an external switch to have multiple functions; or a power on reset circuit; or multi-output charge status pin.

Abstract: A DC-DC converter for converting DC power received from a high-voltage DC power supply to a well-regulated output voltage that is significantly lower than the received voltage. The converter includes a regulated voltage-reduction stage which receives high-voltage DC electrical power and supplies DC electrical power at a voltage which is lower than that received. The converter also includes a separately regulated electrically isolated stage, energized by electrical power received from the voltage-reduction stage, that supplies DC electrical power to a load at the significantly lower output voltage. A feedback circuit couples an output signal from the output of the isolation-stage for regulating operation of the voltage-reduction stage and of the isolation stage.

Abstract: A sequential burst mode regulation system to deliver power to a plurality of loads. In the exemplary embodiments, the system of the present invention generates a plurality of phased pulse width modulated signals from a single pulse width modulated signal, where each of the phased signals regulates power to a respective load. Exemplary circuitry includes a PWM signal generator, and a phase delay array that receives a PWM signal and generates a plurality of phased PWM signals which are used to regulate power to respective loads. A frequency selector circuit can be provided that sets the frequency of the PWM signal using a fixed or variable frequency reference signal.

Abstract: An integrated controller for the detection and operation of both PC Cards, smart cards and passive smart card adapter cards. In one aspect, the invention detects the presence of standard expansion cards or passive smart card adapters by utilizing the reserved detection and voltage selection signal area defined by the PC Card specification. In another aspect, the invention provides an integrated controller that includes logic to operate either a standard expansion card or a passive smart card adapter by reassigning certain PC Card signal lines to operate a standard expansion card or a passive smart card adapter, thereby eliminating the need to provide pins in addition to those defined by the PC Card specification.

Abstract: An active transient-control circuit included in a power supply responds swiftly to changes occurring in the output-power voltage produced by a power converter to reduce transient changes in the output-power voltage caused by sudden, substantial changes in the electrical current drawn by the load. To respond in this way, when the output-power voltage has a magnitude less than a lower pre-established-voltage threshold, the active transient-control circuit supplies electrical energy directly to the load from the input electrical power thereby augmenting output electrical power supplied to the load by the power converter. Correspondingly, when the output-power voltage has a magnitude that exceeds an upper pre-established-voltage threshold, the active transient-control circuit draws electrical energy directly from the output of the power converter.