Integrated circuit incorporating compensating heater - has integral heater enclosing circuit, with elements between conductors trimmed by laser beam

摘要

The printed circuit which may incorporate a differentiating stage with differential amplifiers has a heat sensitiVe region (12) with conductors (13,14,15) terminating in connection strips. These incorporate compensating elements (19,20), and the heat sensitive region is enclosed by an integrated heating element (16) with two further connecting strips (17,18) attached to it. This is used to compensate for thermal drift, and a predetermined temp. is maintained by applying a certain electrical signal to the connections. The compensating elements are formed by thin film resistances which can be trimmed by elements (29,30) between the conductors (26,27, 28) which can be partially melted by a laser beam. The heating element is carried by the substrate. A control system can be used to monitor and equalise the temp. differences.