Solid state optically coupled power switch with light induced or modified voltage applied or removed at one or more MOSFET gate and source electrode pairs to shift each MOSFET between its high and low impedance states and in various circuit arrays for ac or dc switching and/or cross points switching or mechanical Form C relay substitution or other purposes

Solid state optically coupled electrical power switch

A process for etching and filling a trench prevents the top opening of the trench from being closed off prior to the trench being completely filled. After a masking layer is deposited and patterned, the trench is etched and then the masking layer is removed. A first liner insulating layer is grown or deposited and is then etched anisotropically to remove the layer from the top surface of the substrate as well as from the top portion of the walls of the trench. A second, thinner liner layer is grown or deposited on the exposed portion of the walls of the trench to provide surface and edge protection. A polysilicon layer is then deposited to fill the trench and is planarized to remove the portion deposited on the top surface of the substrate. Alternatively, the thinner oxide liner can be omitted, and the polysilicon is removed by chemical mechanical polishing until the trench liner oxide appears on the top surface. An overlaying insulation layer is then deposited. A passivation layer may be subsequently deposited on the bottom surface. The process is particularly suited for etching and filling steps that leave a re-entrant profile at the top of the trench. The trench structure may provide dielectric isolation for the cells of a photovoltaic generator. An MOS-gated device may be integrated into the same chip and may be a lateral or vertical MOSFET or a lateral or vertical IGBT.

Process for filling deep trenches with polysilicon and oxide

Self-contained solar-powered long-life intelligent illuminated road markers are provided comprising a one-piece housing formed of optionally colored plastic capable of transmitting light. Light is reflected by reflective coating or generated internally by LED which is powered by a long life battery, the charging of which is controlled by electrical circuitry which comprises a peripheral interface controller. The electrical circuitry provides intelligent control for a variety of modes corresponding to diverse driving conditions, and can enter a low-power sleep mode to conserve battery life.

Long life intelligent illuminated road marker

A meter for measuring electric power consumed by a plurality of branch circuits includes interchangeable current transformers including respective transformer memories for storage of transformer characterization data and enables self-discovery of a phase shift induced by respective current transformers and the phase of current conducted by each branch circuit.

Branch current monitor with calibration

A current switch is automatically calibrated when a flow of electric current is initiated in a power cable.

Current switch with automatic calibration

A power MOSFET is controlled by illuminating a single photovoltaic generator which produces an output current which charges the gate capacitanace of the power MOSFET to turn on the device. A sensing impedance which may be a diode, MOSFET or other component is connected between the photovoltaic generator and the gate of the power MOSFET. The sensing impedance in the disclosed embodiment is a diode. The sensing impedance forces the power MOSFET gate voltage instantaneously to follow the photovoltaic generator output voltage. The diode is connected in series with the charging circuit and a switching transistor is connected in parallel with the gate capacitance of the MOSFET. The switching transistior base is coupled to the output of the photovoltaic source so that, when the photovoltaic source turns off, and the voltage of the photovoltaic source decays below a predetermined value, the switching transistor turns on to short-circuit the MOSFET gate capacitance so that it can immediately discharge to provide fast turn-off of the power MOSFET. A dV/dt clamping circuit is provided to prevent false charging of the power MOSFET gate through its drain-to-gate capacitance.

Howard William Collins

Papers

Fast turn-off circuit for photovoltaic driven MOSFET

Solid state relay