Abstract: A detector circuit monitors the phase relationship between the lamp voltage and the excitation voltage, and if one or more conditions are met, triggers the open lamp protection process in a discharge lamp system. The detection circuit can be incorporated into a lamp voltage feedback circuit and implemented on the integrated circuit level with less cost and circuit complexity.

Abstract: Methods and apparatus are disclosed for balancing currents passing through multiple parallel circuit branches and in some cases through parallel fluorescent lamps. Single transformers with multiple-leg magnetic cores are wound in specific manners that simplify current balancing. Conventional three-legged EE-type magnetic cores, with disclosed windings are used to balance current in circuits with three or more parallel branches, such as parallel connected Cold Cathode Fluorescent Lamps (CCFLs).

Abstract: A circuit comprises a detector circuit and a protection triggering circuit in a discharge lamp system. The detector circuit detects both open lamp and shorted lamp conditions and is coupled with detecting devices, such as sensing capacitors. A DC bias is added to the sensing capacitors so that capacitor voltages are always greater than zero volts. The output voltage of the detector circuit is coupled to the protection triggering circuit, which triggers an open lamp protection when open lamp condition occurs and a shorted lamp protection when shorted lamp condition occurs.

Abstract: Control methods and apparatus are disclosed for operating a full-bridge inverter at resonant frequency mode, hybrid frequency mode, and fixed frequency mode. The operating frequency of the inverter equals to the user programmed frequency if the user programmed frequency is above the resonant tank frequency; and the operating frequency is synchronized with the resonant tank frequency if the user programmed frequency is below the resonant tank frequency.

Abstract: A method for responding to an open lamp condition in a discharge lamp system is disclosed. The method monitors a current feedback signal flowing through a lamp and a voltage feedback signal indicative of a voltage across said lamp. A switch is used to switch between the current feedback signal to the voltage feedback signal upon detection of an open lamp condition.

Abstract: Control methods and apparatus are disclosed for operating an inverter at resonant mode, where the inverter adapts its frequency to the resonant tank characteristics before a lamp is struck, and operates at fixed frequency after the lamp is struck. Disclosed embodiments combine the advantages of operation in fixed mode as well as the variable mode.

Abstract: Methods and apparatus are disclosed for protecting circuits from damages caused by elevated temperatures. Presented embodiments illustrate IC thermal protection circuits that shut down power delivery circuits when the circuit temperature reaches a predefined upper threshold and restart the circuit when the circuit cools down to a predefined lower threshold. Other embodiments provide soft shutdown and soft restart, where not only the temperature range between the shutdown and the restart is predetermined, but also the time between the start of a shutdown process and the complete shutdown is controllable.

Abstract: The present invention introduces methods and circuits to amplify audio signals for driving speakers. An additional feedback circuit is added in an audio amplifier to couple the amplifier stage and output stage of the audio amplifier. The feedback circuit turned off as long as output voltages of the audio amplifier are not near saturation. The feedback circuit is turned on to reduce audible noises if output voltages of the audio amplifier are near saturation.

Abstract: The present invention provides a method and apparatus for dynamically correcting overshoot and undershoot errors in an analog integrated circuit by improving the reaction time (?t) of the analog integrated circuit. Equivalently, an error correction circuit is disclosed including an overshoot correction circuit and an undershoot correction that are only activated to reduce overshoot and undershoot errors by increasing the bandwidth of the integrated circuit when either undershoot or overshoot errors are detected.

Abstract: An inverter comprising a low-side switching element in series with a first primary winding; a high-side switching element in series with a second primary winding, where the combination of the low-side switching element and first primary winding is connected in parallel with the combination of the high-side switching element and the second primary winding; and a clamping capacitor having one terminal connected to the first primary winding and having a second terminal connected to the second primary winding. Other embodiments are described and claimed.

Abstract: A fault detection circuit and a short-circuit detection circuit for a Cold Cathode Fluorescent Lamp (CCFL) driver integrated circuit having a power bridge and a CCFL load are disclosed that includes a reference circuit operable to generate a reference current in response to an external component, a replica component having a dimension substantially less than the components of the power bridge, a multiplexer circuit, and a comparator circuit. The replica component and the multiplexer circuit pass the reference current and the replica current to the comparator circuit respectively.

Abstract: A detector circuit monitors the phase relationship between the lamp voltage and the excitation voltage, and if one or more conditions are met, triggers the open lamp protection process in a discharge lamp system. The detection circuit can be incorporated into a lamp voltage feedback circuit and implemented on the integrated circuit level with less cost and circuit complexity.

Abstract: A battery charging circuit monitors the IC temperature through monitoring the charging die temperature, or directly monitoring the IC temperature using a temperature sensor. A maximum temperature allowed for the charging die is predetermined. The charging circuit is capable of reducing charging current at the predetermined maximum temperature value. The charging die signal is compared by a reference signal to achieve the reduction of charging current at the maximum allowed temperature value.

Abstract: A level-shifting amplifier is provided for level-shifting an input signal with a voltage magnitude that exceeds a supply voltage of the amplifier. In operation, the amplifier has an input impedance of greater than 100M Ohms.

Abstract: A method and apparatus for a single-wire serial communication includes defining a predetermined short pulse as data and a predetermined long pulse as a data separator.

Abstract: The described DC to AC inverter efficiently controls the amount of electrical power used to drive a cold cathode fluorescent lamp (CCFL). Additionally, during striking of the CCFL, a higher energy initial energy pulse is used. During normal operation, a lower energy pulse is used.

Abstract: The present disclosure introduces a simple method and apparatus for converting DC power to AC power, and, specifically, to single-ended inverter circuits for driving discharge lamps such as a Cold Cathode Fluorescent Lamp (CCFL) or an External Electrode Fluorescent Lamp (EEFL). Among other advantages, these circuits offer nearly symmetrical voltage waveform to drive discharge lamps when the duty cycle is close to 50%. They also eliminate the high current and high voltage resonant capacitor on the primary side, and reduce the voltage rating of a primary switch to twice the input voltage without the need for snubber circuits. The recommended inverters can be used to efficiently drive discharge lamps at low cost, particularly for applications with a narrow input voltage range. The lamp current can be regulated through the duty cycle modulation of the main switch.

Abstract: A technique is described that reduces parasitic losses in circuits used to drive current through a load. An example of a system according to the technique includes four switches in series with five pins such that one pin is connected to ground. An example of an apparatus according to the technique may include four switches in series with two switches connected to ground and to a load and two switches connected to a power source. An example of a method according to the technique involves producing a voltage waveform having three phases.

Abstract: Methods and apparatus are disclosed for providing stable voltage references from within a low dropout voltage regulator. Some embodiments utilize dependable semiconductor inherent attributes to generate a voltage reference, such as a band-gap voltage reference.

Abstract: The present disclosure introduces a simple method and apparatus for converting DC power to AC power for driving discharge lamps such as a cold cathode fluorescent lamp (CCFL), an external electrode fluorescent lamp (EEFL), or a flat fluorescent lamp (FFL). Among other advantages, the invention allows the proper protection under short circuit conditions for applications where the normal lamp current is greater than safe current limit.