Telefonaktiebolaget Lm Ericsson (publ)

Torbjorn R Olsson

Per-Olof Magnus Brandt

Stig C Ernolf

Bjorn T Kassman

Per-Ove Nilsson

Karl Gustaf Olsson

Leif Lingstrom

Rolf I Kjellsson

Lars H Widoff

A device for controlling a current to a load by means of mirroring is described. Two transistor units are connected to a common reference point. By driving a current through one of the transistor units, a corresponding current is generated in the second transistor unit. A control unit, connected between the transistors can regulate a voltage difference between transistors. Accordingly, the size of the load attached is determined through mirroring with accuracy and minimal power loss.

Method and apparatus for measuring and regulating current to a load

The present invention relates to a printed circuit board provided with electrical contact devices (7) and intended to be mounted in the back plane of a card frame (2) such as to form a magazine (1) in which printed circuit cards (6) having electrical contact devices (8) corresponding to the contact devices (7) on the board can be inserted at right angles to the back plane. The circuit board (3) forms an electrical connecting unit for the circuit cards in the back plane of the magazine. In accordance with the invention, the circuit board is configured to provide a self-supporting and stiffening structure in the form of a sandwich element (10).

Printed circuit board for mounting in a backplane

Growing community of inventors

Tullinge, Sweden

Torbjorn R Olsson