Contactless interface circuitry for chip=card e.g. for car-lock - has both currents, rectified from secondary coil voltages, electronically linked in current control circuit

摘要

The two currents are derived from rectifiers (G1, 2) supplied by secondary coils (SS1, 2) and are linked together electronically in a current control circuit such that the total current used by a capacitor (C1) is additively coupled to the two currents (I1, 2). The linking forcibly realises an increase of the current (I2) on the secondary side reduction of the other current (I1), and vice versa. Thus the total current consumption is kept constant. The transformer-like trnasmission path provides a contactless voltage changes on the primary of two coils from the secondary side current changes, due to the impedance changes in the transmission path. USE/ADVANTAGE - For telephone cards, car keys etc. with reduced energy losses and improved data transmission.