Abstract: A driver for electroluminescent (EL) lamps is an integrated circuit that includes a first transistor, a second transistor, and an inductor connected in series between the first transistor and the second transistor. The driver also includes at least four output circuits coupled to said inductor for separately driving at least four electroluminescent lamps. The driver further includes memory for storing data representing dimming levels and device addresses. Data is communicated to the driver through a serial interface that recognizes at least one standard protocol.

Abstract: A driver includes a boost converter, a pulse width modulator controlling the boost converter, and a timer controlling the pulse width modulator. The timer, such as a digital counter, causes the pulse width modulator to produce narrow pulses unless or until the end of a period is reached, at which point the pulse width modulator is not controlled by the timer.

Abstract: A driver for a piezoelectric actuator includes a pulse width modulator and an output amplifier packaged as a single semiconductor device, preferably on a single semiconductor die. The driver includes a first boost converter that supplies power to the output amplifier, which preferably has programmable gain. A second amplifier, for driving the gate of a switching transistor in the first boost converter, is powered by a second boost converter. The piezoelectric actuator provides tactile feedback for the keyboard or the display in a battery operated electronic device.

Abstract: A driver includes a boost converter, a pulse width modulator controlling the boost converter, and a timer controlling the pulse width modulator. The timer, such as a digital counter, causes the pulse width modulator to produce narrow pulses unless or until the end of a period is reached, at which point the pulse width modulator is not controlled by the timer.

Abstract: A power supply for driving an EL panel includes an inverter that produces a polarity reversing voltage at a pair of output terminals. A switching circuit coupled to the output terminals and to at least one EL lamp applies alternating current to the at least one EL lamp in the on state and blocks current from the EL lamp in the off state. The switching circuit includes a first bidirectional switch connecting a first terminal of the EL lamp to a first output terminal and a second bidirectional switch connecting a second terminal of the EL lamp to a second output terminal.

Abstract: A driver for electrically causing a MEMS device to change shape or position includes an amplifier having a first feedback loop and a second feedback loop. The first feedback loop stabilizes output voltage and the second feedback loop reduces current changes through the MEMS device to zero.

Abstract: A driver for electroluminescent (EL) lamps is an integrated circuit that includes a first transistor, a second transistor, and an inductor connected in series between the first transistor and the second transistor. The driver also includes at least four output circuits coupled to said inductor for separately driving at least four electroluminescent lamps. The driver further includes memory for storing data representing dimming levels and device addresses. Data is communicated to the driver through a serial interface that recognizes at least one standard protocol.

Abstract: An inverter for supplying alternating current to an EL lamp includes a first charging path, a first discharging path, a second charging path, a second discharging path, the paths intersecting at a node, wherein the node is the output of the inverter from which the alternating current flows. The charging paths include inductive boost circuits having a common inductor.

Abstract: A light source and a liquid crystal display are separated by a transparent, color graphic to simulate a color liquid crystal display. The light source preferably produces a substantially white light, as is available by cascading materials, and includes discrete or diffuse sources. The liquid crystal display is preferably positive (black on white) rather than negative to reveal more of the graphic. With an EL light source, the graphic can be printed on the transparent substrate of the EL lamp. In liquid crystal displays having a transflective layer, the transflective layer can be located between the light source and the graphic layer.