ELECTROSTATIC DISCHARGE PROTECTION CIRCUIT FOR READ HEAD

摘要

PURPOSE: An electrostatic discharge protection circuit for a read head is provided to prevent currents from damaging the read head by providing an alternative path for the currents associated with sparkovers. CONSTITUTION: A parasitic shield layer(124) is provided in close proximity to magnetic shield layers(113,115). The electrical potential of the parasitic shield layer(124) is held essentially equal to the electrical potential of a sensor element(111). If charges accumulate on the conventional shield layer, current will flow to the parasitic shield layer(124) at a lower potential than would be required for current to flow between the conventional shield layer and the sensor element(111). Alternatively, conductive spark gap devices are electrically coupled to sensor element leads and each magnetic shield layer. Each spark gap device is brought within very close proximity of a substrate to provide an alternative path for charge that builds up between the sensor element(111) and the substrate to be discharged. The ends of the spark gaps that are brought into close proximity of the substrate are preferably configured with high electric field density inducing structures which reduce a voltage required to cause a sparkover between the spark gap device and the substrate.