Abstract:
There is provided a driving circuit for powering a plurality of light sources. The driving circuit includes a power converter, a plurality of switching regulators and a plurality of switching balance controllers. The power converter is operable for receiving an input voltage and for providing a regulated voltage to the light sources. The switching regulators are operable for adjusting forward voltages of the light sources respectively. The switching balance controllers are operable for generating pulse modulation signals to control the switching regulators respectively.
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/AC cold cathode fluorescent lamp (CCFL) inverter circuit includes a transformer with a primary winding and a secondary winding for providing increased voltage to a CCFL, a first and second MOSFET switches for selectively allowing direct current of a first polarity and a second polarity to flow through the transformer respectively. The primary and secondary windings of the transformer are electrically coupled to ground. A capacitor divider is electrically coupled to the CCFL for providing a first voltage signal representing a voltage across the CCFL. A first feedback signal line receives the first voltage signal. A timer circuit is coupled to the first feedback signal line for providing a time-out sequence of a predetermined duration when the first voltage signal exceeds a predetermined threshold. A protection circuit shuts down the first switch and the second switch when the first voltage signal exceeds the predetermined threshold after the predetermined duration.
Abstract:
A DC/AC inverter and method thereof is disclosed. The DC/AC inverter for driving a load includes a DC power supply for supplying a DC input voltage, a converter circuit coupled to the DC power supply which converts the DC input voltage into an AC signal used to drive the load, and a control circuit coupled to the converter circuit which sets a frequency of the AC signal. The control circuit is further capable of operating the DC/AC inverter in a fixed frequency mode and in a variable frequency mode in accordance with the DC input voltage and the load condition.
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.
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.
Abstract:
A method according to one embodiment may include generating, by a controller, a plurality of control signals to control operations of inverter circuitry to generate an AC signal from a DC signal. The method of this embodiment may also include using the control signals generated by the controller to also control operations of power factor correction (PFC) circuitry, via the inverter circuitry, to enable the PFC circuitry to generate power factor correction of an input source coupled to the PFC circuitry and the inverter circuitry. Of course, many alternatives, variations, and modifications are possible without departing from this embodiment.
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 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.
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.