In a drive circuit for driving an electroluminescent device having an electroluminescent lamp, a battery, and a frequency divider circuit for generating a plurality of signals, including a first signal, the improved voltage-boosting circuit comprising first and second inductors electrically connected to the battery; a digital logic gate electrically connected to the frequency divider circuit; a first transitive switch electrically connected to the frequency divider circuit for receiving the first signal, and electrically connected to the first inductor for providing the first signal to the first inductor; and, a second transitive switch electrically connected to receive an output signal from the digital logic gate and electrically connected to the second inductor for providing the output signal to the second inductor, wherein the first and second inductors are caused to alternately provide high voltage pulses for driving the electroluminescent lamp. The digital logic gate may comprise a NOR gate having two terminals, one of which is electrically connected to receive a dimming signal for disabling the second inductor thereby reducing the electroluminescent lamp brightness. The operator of the electroluminescent lamp may selectively activate the digital logic gate to reduce lamp brightness.
A personal electronic device includes and inverter having a single inductor for powering an EL lamp and a buzzer. The lamp and the buzzer are coupled together to the output of the inverter and are in parallel with each other or are coupled in series between a source of direct current and ground.
A full-wave driving circuit for multiple electroluminescent lamps includes circuitry at a collective first end of the electroluminescent lamps for boosting of both positive and negative waves, and control elements at second ends of the electroluminescent lamps for turning on/off individual lamps at different times, whereby single or multiple electroluminescent lamps can be driven to flash at the same time.
A method for dimmable control of a multiple output EL lamp driver is disclosed. The multiple output EL lamp driver has a power converter. A plurality of EL lamps are provided wherein one terminal of each EL lamp is coupled to a single common terminal. A plurality of half bridge circuits are provided wherein each circuit has an output impedance. One half bridge circuit is coupled to the single common terminal and each remaining terminal of each EL lamp is coupled to a separate individual half bridge circuit. A logic circuit is coupled to each of the half bridge. An oscillator is coupled to the logic circuit. The method comprises: minimizing the output impedance of the half bridge circuit coupled to the single common terminal to prevent to brightness crosstalk between EL lamps; selecting output impedances of remaining half bridge circuits to produce rounded waveforms across terminals of the EL lamps; and manipulating a drive waveform of one of the plurality of EL lamps to control brightness.
An inductive boost circuit is added in parallel with an inverter to increase current to an EL lamp. The inverter and the boost circuit each include a switching transistor. The switching transistor in the inductive boost circuit may be matched to the switching transistor in the inverter and may be driven synchronously with the switching transistor in the inverter.
A power supply for an EL lamp includes a boost circuit and four semiconductor switches connected as a bridge having an AC diagonal and a DC diagonal having one end grounded. The voltage boost circuit is coupled across the DC diagonal and an electroluminescent lamp is coupled across the AC diagonal of the bridge. The two semiconductor switches coupled to ground are SCRs.
