Stmicroelectronics (rousset) Sas

Gary Seigneuret

Christophe Moreaux

Gilles Bas

An electromagnetic transponder includes an antenna circuit, a load, and a charge pump transistor having a current path coupled between the antenna circuit and the load. During operation, a retromodulated signal is transmitted at a first level by biasing the charge pump transistor during a first time period such that an impedance of the antenna circuit has a first impedance value and current flows from the antenna circuit to the load. A retromodulated signal at a second level is transmitted by biasing the charge pump transistor during a second time period such that the impedance of the antenna circuit has a second impedance value different than the first impedance value and current flows from the antenna circuit to the load. The retromodulated signals are transmitted at the first and second levels in a sequence determined to transmit information from the electromagnetic transponder.

Method for modulating the impedance of an antenna circuit

An electromagnetic transponder includes an antenna circuit capable of providing signals to a charge pump. The pump includes a first transistor connected to a first capacitor. The transponder also includes means for applying a voltage alternating between first and second values between the gate and the conduction terminal on the side of the first capacitor of the first transistor.

Growing community of inventors

Saint Thibault des Vignes, France

Gary Seigneuret