BATTERY CHARGER OPERATING "ALL OR NOTHING" WITH A PROTECTIVE POWER SUPPLY CIRCUIT FOR MONOLITHIC INTEGRATED CIRCUITS USING THE ANTENNA ENERGY

The invention concerns an integrated radiofrequency circuit ( 1 ) including an antenna ( 2 ) for receiving radiofrequency signals, a rechargeable battery ( 3 ) and a battery charger ( 5 ) using said radiofrequency signals to charge said battery. The circuit is characterized in that said battery charger is integrated in the same substrate as the integrated radiofrequency circuit and in that said battery charger includes calibrating means, a current source calibrated by said calibrating means and delivering a charge current of constant maximum intensity drawn from the received radiofrequency signals and a comparator between a reference quantity representative of the end of battery charge level and a variable quantity representative of the battery charge level supplying at output a control signal (batchend) for charging or not charging the battery.