Northwest University

Potchefstroom University for Christian Higher Education

Ambixtra (pty) Ltd.

Barend Visser

Petrus Paulus Kruger

Ocker Cornelis De Jager

Petrus Paulus Krüger

Carolus Johannes Reinecke

Hendrik Johannes Stephanus Van Der Walt

Ocker Cornelius De Jager

Roelof Cornelius Botha

An ignition system () comprises a high voltage transformer () comprising a primary winding () and a secondary winding (). A primary resonant circuit () is formed by the primary winding () and a primary circuit capacitance (). A secondary resonant circuit () is formed by an ignition plug (), as a load, the secondary winding (); the ignition plug () being represented by a secondary circuit capacitance () and a secondary circuit load resistance (Rp) put in parallel. Said load resistance value varies during an ignition cycle. The primary resonant circuit () and the secondary resonant circuit () have a common mode resonance frequency (f) and a differential mode resonance frequency (f). A controller () is configured to cause a drive circuit () to drive the primary winding at a frequency, which is either the common-mode resonance frequency (f) or the differential mode resonance frequency (f) and is connected to a feed-back circuit () to adapt the frequency of the primary winding to the variable load resistance.

Ignition system for an internal combustion engine and a control method thereof

An ignition plugcomprises an elongate cylindrical bodyof an electrically insulating material having a first end, a second endopposite to the first end and a first faceat the first end. A first elongate electrodehaving a first endand a second endextends longitudinally in the body. The first electrode terminates at the first end thereof a first distance dfrom the first end of the body in a direction towards the second end of the body. The body hence defines a blind boreextending between the first end of the first electrode and the first end of the body. A second electrode is provided on an outer surface of the body and terminates at one of a) flush with the first faceof the body and b) a second distance dfrom the first end of the body in a direction towards the second end of the bod.

Ignition plug

A switched mode drive circuitcomprises a first switchhaving a first terminaland a second terminal, a second switchhaving a first terminaland a second terminal, an inductive componentcomprising at least a first winding parthaving a first endand a second endand a second winding parthaving a first endand a second endand an energy storage devicehaving a first poleand a second pole. The first and second terminals of each of the first and second switches and the first and second ends of each of the first and second winding parts are connected in series over the first and second poles of the energy storage device and the first and second winding parts are configured in one of a common mode and a differential mode.

Switched mode drive circuit

An ignition system () comprises a spark plug () having a first end () defining a spark gap () between a first electrode () and a second electrode (). A transformer () comprises a primary windingand a secondary winding () also forms part of the system. The secondary winding is connected in a secondary circuit to the first electrodeand the secondary winding has a resistance of less than 1K&#x3a9; and an inductance of less than 0.25 H. A drive circuit () is connected to the primary winding.

Ignition system

The transformer () comprises a core (), a primary winding () and a secondary winding. The core comprises an elongate limb () having a main axis () and comprising a plurality of segments (to) of a magnetic material and gaps (to&#x2212;1) between segments arranged in alternating relationship along the main axis (). The main axis () is parallel to a direction of a magnetic field in the limb (). Each gap has a linear segment separating extent (gj which is parallel to the main axis (). The value of n is larger than three and the gaps are filled with an isolation medium ().

Segmented core transformer

A distributed low noise amplifier (DLNA) comprises at least a first amplifier partproviding a first pathform an input of the amplifier to an output of the amplifier and a second amplifier partproviding a second pathfrom the input to the output. Each of the first and second paths being associated with a respective and different change in phase. The difference being larger than degrees in a noise suppression band to cause a phase difference between noise generated by the amplifier arrangement propagating along the first and second paths and destructive interference of the noise before the output of the DLNA, thereby to suppress noise in the noise suppression band. The respective gains of the amplifier partstomay decrease in a direction from the input of the amplifier to the output thereof.

Distributed low noise amplifier

An ignition system () comprises a spark plug () having a first end () defining a spark gap () between a first electrode () and a second electrode (). A transformer () comprising a primary windingand a secondary winding () also forms part of the system. The secondary winding is connected in a secondary circuit to the first electrodeand the secondary winding has a resistance of less than 1 k&#x3a9; and an inductance of less than 0.25 H. A drive circuit () is connected to the primary winding.

An insulated gate semiconductor device () includes a gate (), a source terminal (), a drain terminal () and a variable input capacitance at the gate. A ratio between the input capacitance (C) when the device is on and the input capacitance Cwhen the device is off is less than two and preferably substantially equal to one. This is achieved in one embodiment of the invention by an insulation layerat the gate having an effective thickness dlarger than a minimum thickness.

Fast switching power insulated gate semiconductor device

A hardware random number generator (RNG) has a source of entropy for providing a bit stream (DIS) comprising successive bits of a first state and a second state. The RNG includes a first digital corrector circuit configured to provide from two successive bits in the bit stream an output bit of an output bit stream according to a first scheme to ensure that bits in the output bit stream are independent from one another. A serially connected second digital corrector circuit ensures that the bits in the output bit stream are also unbiased, so that the output bit stream is truly random. A Gaussian generator connected to an output of either the first corrector or the second corrector generates from the output bit stream words having standard Gaussian deviates.

Hardware generator for uniform and Gaussian deviates employing analog and digital correction circuits

A method of producing ozone comprises the steps of generating intermittent bursts of corona discharge in an electrode regionand passing oxygen-containing fluid through the region, thereby to cause ionization of the oxygen. The electrode is energized by a train of voltage pulses. Each pulse has a rise time of better than 2 kV/100 ns.

Method and apparatus for producing ozone

A circuit for driving a MOSFET () includes a capacitor () and a switch () connected to a gate () of the MOSFET. The circuit applies a charge pulse to the gate of the MOSFET so as to switch the MOSFET between one of an on state and an off state and the other of the one state and the off state. The duration of the pulse is such that the pulse is substantially complete prior to switching of the MOSFET. The pulse causes a voltage on the gate for a short period to be raised above a maximum gate-to-source rating of the MOSFET, thereby to improve the switching speed of the MOSFET.

Method for driving an insulated gate semiconductor device using a short duration pulse

An amplifier arrangement ( ) comprises an input node ( ) and an output node ( ). A plurality of amplifiers ( ) to ) are connected in respective parallel paths ( to ) extending between the input node and the output node. The input node divides an input signal S (t) into signal S (t) to S (t) and feeds the signal parts along respective paths to the output node. The paths have equal propagation delays for the signal parts, to provide at the output node an output signal S (t) comprising a coherent summation of the signal parts and an incoherent summation of noise.

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Potchefstroom, South Africa

Barend Visser