Abstract: A voltage generator is used for generating a voltage reference with high power supply rejection. One embodiment of the circuit includes a voltage regulator and a bandgap voltage circuit and an amplifier. The voltage regulator including an input node is coupled to an external power supply for generating a regulated voltage source. A bandgap voltage circuit includes a first and a second resistor and a first and a second transistor to generate a voltage difference between the base-to-emitter voltages of the first and the second transistors. The second resistor is coupled to the first resistor and the first transistor for generating the first predetermined voltage in response to the voltage difference. An amplifier circuit is coupled to the first transistor of the bandgap voltage circuit for receiving a first amplifying signal and generating an amplified signal so as to regulate the regulated voltage source.

Abstract: An over voltage transient controller to protect a rechargeable battery from an over voltage transient condition. The over voltage transient controller may comprise a comparator to compare a first signal with a second signal representative of a reference voltage level and to provide an output signal representative of an over voltage transient condition to a switch if the first signal is greater than or equal to the second signal. The switch is responsive to the output signal to protect the rechargeable battery from the over voltage transient condition. The over voltage transient controller may further comprise a DAC, wherein the second signal is based, at least in part, on an output of the DAC. An apparatus comprising a charge switch and such an over voltage transient controller is also provided.

Abstract: A circuit is used for controlling charging and discharging a battery. The circuit comprises a first MOSFET for controlling discharging the battery, and a second MOSFET coupled in series to the battery and the first MOSFET for controlling charging the battery. The first and second MOSFETs have body diodes respectively, and the first body diode of the first MOSFET and the second body diode of the second MOSFET are coupled in opposite directions. A load is coupled to the battery and a common node between the first and second MOSFETs such that power in the battery is delivered to said load when the first MOSFET is turned on. The circuit further comprises a power source coupled to the second switch in series and power is delivered from the power source to the battery when the first and second MOSFETs are turned on.

Abstract: An apparatus and method for operating a phase-locked loop circuit are disclosed. The phase locked loop circuit includes a plurality of resistive elements and a plurality of capacitive elements that are distributed in a charge pump, a loop filter and a voltage controlled oscillator. The plurality of resistive elements have a plurality of resistances that vary in proportion to each other. The plurality of capacitive elements have a plurality of capacitive elements that vary in proportion to each other. A damping factor of the phase-locked loop circuit is maintained substantially constant by the plurality of resistive elements and the plurality of capacitive elements.

Abstract: A supply topology comprising an AC to DC or DC to DC adapter and an electronic device with an active system, a battery, and an adapter controller implements closed-loop control of adapter output voltage to limit power consumption by the electronic device to a value related to maximum adapter power. The adapter couples a signal representing maximum adapter power to a control line connected to the electronic device and the electronic device couples an error signal representing the difference between instantaneous power consumption and adapter maximum power onto the same control line. The adapter adjusts its output voltage in response to the magnitude of the error signal. An adapter controller in the electronic device sets a limit for allocating current to battery charging from the signal representing maximum adapter power, with battery charging current approaching zero as instantaneous power consumption approaches maximum adapter power.

Abstract: A method according to one embodiment may include selecting at least one power supply, among a plurality of different power supplies, and coupling at least one available power supply to a load. The method may also include selecting at least one charging mode, among a plurality of different charging modes, to charge a rechargeable battery. Of course, many alternatives, variations, and modifications are possible without departing from this embodiment.

Abstract: A DC to DC converter for converting an input DC voltage to an output DC voltage. The DC to DC converter may include at least one switch, an inductor coupled to the at least one switch, and a controller capable of providing a control signal. The at least one switch may be responsive to the control signal in a first state to enter an ON state for an ON time interval, the ON time interval based on the input DC voltage and a constant. An electronic device including such a DC to DC converter and related methods are also provided.

Abstract: A controller for providing out of phase drive signals to a power converter having at least a first power unit and second power unit. The controller may comprise input circuitry adapted to receive a first signal from a first path and a second signal from a second path and provide an output signal in response to a difference between the first and second signals. The first signal may be representative of a current level of the first power unit during a first time interval and the first signal representative of a current level of the second power unit during a second time interval. The controller may further comprise output circuitry responsive to the output signal from the input circuitry to provide the out of phase drive signals to the first and second power unit.

Abstract: A method according to one embodiment may include providing power to at least one light source. The method of this embodiment may also include detecting the frequency of at least one vertical synchronization signal, among a plurality of different synchronization signals, and controlling the power to at least one light source based on, at least in part, the detected frequency of at least one vertical synchronization signal. Of course, many alternatives, variations, and modifications are possible without departing from this embodiment.

Abstract: A DC to DC converter to convert an input voltage to an output voltage. The DC to DC converter may include a pair of switches including a high side switch and a low side switch, an inductor coupled to the pair of switches; and a controller. The controller may be configured to estimate a zero crossing of an inductor current through the inductor without directly measuring said inductor current. An associated method is also provided.

Abstract: A power converter includes a transformer having a primary winding and a secondary winding, and a plurality of switches coupled to the primary and secondary winding, the plurality of switches responsive to at least one control signal to short both the primary and secondary winding during a first reset time interval. An electronic device including such a power converter and related methods are also provided. A power converter having a plurality of DC to DC converters coupled in parallel is also provided.

Abstract: The present invention provides an integrated VPN/firewall system that uses bath hardware (firmware) and software to optimize the efficiency of both VPN and firewall functions. The hardware portions of the VPN and firewall are designed in flexible and scalable layers to permit high-speed processing without sacrificing system security. The software portions are adapted to provide interfacing with hardware components, report and rules management control.

Abstract: A current mode charger controller for controlling a DC to DC converter. The current mode charger may include a first error amplifier having an output coupled to a common node. The first error amplifier may be configured to compare a first signal representative of a charging current provided to a rechargeable battery with a maximum charging current and provide a current control signal in response to the comparison. The current mode charger controller may further include an internal compensation network coupled to the common node, and a comparator configured to compare an inductor current signal representative of an inductor current through an inductor of the DC to DC converter with a compensation signal. The need for any external compensation for the current mode charger controller may be eliminated.

Abstract: An over voltage transient controller to protect a rechargeable battery from an over voltage transient condition. The over voltage transient controller may comprise a comparator to compare a first signal with a second signal representative of a reference voltage level and to provide an output signal representative of an over voltage transient condition to a switch if the first signal is greater than or equal to the second signal. The switch is responsive to the output signal to protect the rechargeable battery from the over voltage transient condition. The over voltage transient controller may further comprise a DAC, wherein the second signal is based, at least in part, on an output of the DAC. An apparatus comprising a charge switch and such an over voltage transient controller is also provided.

Abstract: A DC to DC converter includes a comparator, a driver, and a pair of switches. The comparator compares the output voltage with a reference voltage signal and generates a PWM signal. The driver drives the switches so as to force the output voltage to follow the reference signal. In a multiphase architecture, two or more such converter circuits are incorporated to minimize the output voltage ripple and further reduce the recovery time. In a two-phase architecture, two reference signals are phase-shifted by 180 degrees. In an N-phase architecture, the reference signals are phase-shifted by 360/N degrees.

Abstract: Power supply circuit for LCD backlight and method thereof are disclosed in the present invention. The power supply circuit includes a power bus, a boost converter, a buck converter and a controller. The power bus supplies power to a load. The boost converter and buck converter are coupled to the power bus respectively for storing the power from the power line and restoring the power to the load. A controller is further coupled to the buck and boost converter for enable them alternatively according to a pulse width modulation (PWM) signal.

Abstract: A selector circuit configured to select among a DC power source and a plurality of batteries for an electronic device. The selector circuit is responsive to an output signal from an associated power management unit. The selector circuit is further configured to permit parallel operation of two or more of the batteries. The selector circuit may further act to independently verify power conditions and override instructions from the PMU in certain instances to enhance power supply safety and battery life such as by preventing inter battery current flow from a higher potential battery to a lower potential battery coupled in parallel.

Abstract: A method is used for charging a battery. According to the method of the present invention, the battery is first charged to a predetermined voltage at a substantially constant current. Then, the charging current is disabled. A pulsing current is applied to the battery for charging the battery.

Abstract: A selector circuit configured to select among a DC power source and a plurality of batteries for an electronic device. The selector circuit includes a first comparator configured to compare a first input signal representative of a voltage level of the DC power source with a first threshold level and provide a first output signal representative of a difference between the first input signal and the first threshold level, and a selector output circuit. The selector output circuit is configured to provide selector output signals that control selection among the DC power source and the plurality of batteries. The selector output circuit providing said selector output signals to select the DC source and deselect the plurality of batteries if the first output signal is representative of the voltage level of said DC power source being greater than the first threshold level.

Abstract: The present invention provides a driving circuit with protection function for driving a set of external electrode fluorescent lamps (EEFL). The drive circuit includes: a transformer connected to the set of EEFLs; a switching network connected to the transformer which delivers power to the transformer; a sensing circuit connected to the set of EEFLs which detects disconnection if one light source is disconnected; and a controller connected to the switching network which controls the switching network to reduce the total current supplied to the EEFLs which remain connected, if the sensing circuit detects that one EEFL is disconnected. Appropriate protection can therefore be implemented when the EEFL is disconnected on one end or both ends.