Input protection circuit for data line semiconductor circuit - has transformer with centre tap on input coil, with output coil coupled to protection circuit outputs

摘要

The protection circuit (ESS) has a transformer (U1), whose input coil (W1) has a centre tap, while its output coil (W2) is coupled to the protection circuit outputs (A1,2). Two low pass filters in Pi-circuit (L1,C3,4; L2,C5,6) have each two transverse capacitors (C3,4; C5,6) coupled to the centre tap. Longitudinal inductances (L1,2) have inputs coupled each to cable input terminals (E1,2) via a coupling capacitor (C1,2) respectively. Their outputs are each coupled to an outer terminal of the input coil. Two diode pairs (D1-4) in anti-parallel are incorporated between a low pass filter input and the centre tap. USE/ADVANTAGE - For coupling semiconductor circuits to data lines. Compact design for blocking interference voltages and level matching.