A circuit for increasing a supply voltage comprises a transmitter for transmitting a radio signal, with an amplifying device having a supply input for a first supply potential, and a signal output with an antenna connected thereto. Furthermore, the circuit includes a circuit arrangement with a supply input for a second supply potential that is greater than the first supply potential. A voltage rectification circuit is provided that is connected to the signal output of the amplifying device and to the supply input of the circuit arrangement. As a result, an RF input signal is transformed into a rectified voltage. The amplifying device amplifies the radio signal to such an extent that the sum of the rectified voltage and of a first supply voltage is as great as a second supply voltage.