Microsemi Corporation

Other

Microsemi Corp-analog Mixed Signal Group, Ltd.

Newton E Ball

A solar panel has n rows of solar cells in a regular grid array. The cells constituting each row are wired in parallel, the rows are wired in series and an equalizing network of n-1 capacitors are connected in electrical series. In a first configuration, a network of switches connects a first capacitor across the first row, and a second capacitor across the second row, and so on until the n-1th capacitor is connected across the cells of the n-1th row. In a second configuration, the switch network connects the first capacitor across the second row, and the second capacitor across the third row, and so on until the n-1th capacitor is connected across the nth row. This causes the voltage across each row to be substantially equal to the voltage across every other row. Since equal voltage is a hallmark of parallel connection, this voltage equalized series connection is referred to as a virtual parallel connection.

Parallel and virtual parallel interconnection of solar cells in solar panels

High voltage switches are configured with a junction transistor driven with a transformer coupled AC drive signal in the common base configuration or driven by a capacitor coupled charge pump. The high voltage switches may be configured as half wave or full wave switches wherein the junction transistor is driven during one or both half cycles of the AC drive signal. Bipolar switches that can stand off high DC voltage of either polarity, or that can stand off high AC voltage, are configured from two junction transistors with their bases connected and their emitters connected. These switches may also be driven in full wave or half wave mode, by a transformer or by single or dual capacitive charge pumps. Either NPN or PNP transistors may be used. Example drive circuits, which can be constructed as low voltage integrated circuits, are given for all of the switch types.

Charge limited high voltage switch circuits

A sawtooth waveform generator includes an operational amplifier that generates a ramp signal. The ramp signal charges a capacitor connected between the output of the operational amplifier and the inverting input of the operational amplifier. The inverting input is maintained at a substantially constant voltage, which provides a substantially constant charging current through a timing resistor. The connections to the capacitor are switched when the ramp voltage reaches a predetermined level. A control circuit switches the connections to the capacitor in response to a voltage on one terminal of the capacitor to assure that the connections to the capacitor are switched to a configuration to cause the direction of current flow through the capacitor to be reversed as a result of the switching.

Sawtooth waveform generator

An efficient ramp generator uses a reversing switch array to couple a timing capacitor in alternating polarities between an input terminal and an output terminal of an operational amplifier to generate a periodic ramp signal without discharging the timing capacitor between voltage ramps. The reversing switch array includes at least four semiconductor switches controlled by a flip-flop circuit or a latch circuit. The flip-flop circuit or the latch circuit can be driven by an external clock signal or an internal clock signal with a variable frequency.

Ramp generator with fast reset

An apparatus and methods for balancing current in multiple negative impedance gas discharge lamp loads. Embodiments advantageously include balancing transformer configurations that are relatively cost-effective, reliable, efficient, and good performing. Embodiments include configurations that are applicable to any number of gas discharge tubes, such as cold cathode fluorescent lamps. The balancing transformer configuration techniques permit a relatively small number of power inverters, such as one power inverter, to power multiple lamps in parallel. One embodiment of a balancing transformer includes a safety winding which can be used to protect the balancing transformer in the event of a lamp failure and can be used to provide an indication of a failed lamp.

Systems and methods for fault protection in a balancing transformer

An efficient and flexible current-mode driver delivers power to one or more light sources in a backlight system. In one application, the current-mode driver is configured as an inverter with an input current regulator, a non-resonant polarity-switching network, and a closely-coupled output transformer. The input current regulator can output a regulated current source in a variety of programmable wave shapes. The current-mode driver may further include a rectifier circuit and a second polarity-switching network between the closely-coupled output transformer and a lamp load. In another application, the current-mode driver delivers power to a plurality of light sources in substantially one polarity by providing a regulated current to a network of time-sharing semiconductor switches coupled in series with different light sources coupled across each semiconductor switch.

Current-mode direct-drive inverter

Systems and methods for a transformer configuration with a tree topology for current balancing in gas discharge lamps

Method and apparatus to drive LED arrays using time sharing technique

Lamp current control using profile synthesizer

Inverter with two switching stages for driving lamp

An incremental distributed driver divides power delivered to multiple lamps into two power delivery stages. The first power delivery stage operates in voltage-mode to provide a partial operating voltage to the lamps. The second power delivery stage operates in current-mode to regulate current levels for each of the lamps and to provide additional operating voltages for the respective lamps. Each of the power delivery stages includes a polarity-switching network and a common set of driving signals from a controller can be used to drive the polarity-switching networks of both power delivery stages. The first power delivery stage delivers a majority of the power to the lamps and the second power delivery stage facilitates control of individual lamps while providing the remaining power to the lamps.

Incremental distributed driver

An apparatus and methods for balancing current in multiple negative impedance gas discharge lamp loads. Embodiments advantageously include balancing transformer configurations that are relatively cost-effective, reliable, and efficient. Embodiments include configurations that are applicable to an unrestrained number of gas discharge tubes, such as cold cathode fluorescent lamps. The balancing transformer configuration techniques permit a relatively small number of power inverters, such as one power inverter, to power multiple paralleled lamps or paralleled groups of lamps with balancing transformers coupling the lamps or groups of lamps in a zigzag topology. One embodiment of a balancing transformer includes a safety winding which can be used to protect the balancing transformer in the event of a lamp failure and can be used to provide an indication of a failed lamp.

Nested balancing topology for balancing current among multiple lamps

A push-pull driver for powering fluorescent lamps in a backlight system includes a transformer with three primary windings to realize the advantages of both a push-pull switching topology and a full-bridge switching topology. The first and the second primary windings alternately conduct currents in opposite polarities to generate an alternating current signal to power one or more lamps coupled to a secondary winding of the transformer. The third primary winding is short-circuited to preserve energy stored in the transformer in a null state when both the first and the second primary windings are not conducting.

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Anaheim, CA, United States of America

Newton E Ball