Elcometer, Inc.

Diodes Zetex Semiconductors Limited

Alan James Dodd

Craig Maurice Taylor

Simon Trevena Coulton

Maria Isabel Jimenez-Lopez

Rohit Arora

Philip Anthony May

A coating thickness measuring instrument comprising: a magnetic induction probe comprising at least one drive coil and at least one pick-up coil; a driver for driving an alternating current in the or each drive coil; and a detector for detecting the output of the or each pick-up coil; and a processor configured to: apply a transfer function to the detector output to produce an output which corresponds to a measured coating thickness; and, scale both the drive current and detector output simultaneously in response to the output. The scaling may be changed in a step-wise manner. The scaling applied to the drive current may be inversely proportional to the scaling applied to the detector output. The scaling may be defined by a first and second scaling factor, stored as a pair. The instrument may store two or more pairs of scaling factors and select a pair in response to the measured coating thickness.

Coating thickness measurement instrument

A switching regulator (-) supplies a controllable stable average current to a load (), such as series-connected light emitting diodes. A regulator controller () includes a hysteretic comparator () which controls a switch in the form of a transistor () for switching current into an inductor (). The comparator () has upper and lower thresholds. A first circuit comprising a fast current monitor () supplies a first signal to the comparator representing the instantaneous current in the inductor (). A second circuit (, and) supplies a second signal to the comparator representing an error between a desired regulator output and an actual regulator output.

Controller for switching regulator, switching regulator and light source

Growing community of inventors

Bolton, United Kingdom

Alan James Dodd