A circuit having a first input and a second input configured to apply an
alternating voltage, a first output and a second output configured to
supply a rectified and regulated voltage, a rectifier bridge circuit
having a current return circuit, a third transistor and a fourth
transistor, and a controller configured to regulate the voltage between
the first and the second output to a constant value. The current return
circuit is connected to the first input, the second input and to the
second output. The third transistor is configured as a series voltage
regulator and is connected to the first input and the first output. The
fourth transistor is configured as a series voltage regulator and is
connected to the second input and the first output. The controller is
coupled to a control input of the third transistor and to a control input
of the fourth transistor. Further, a method for rectifying and regulating
voltages of a circuit is provided. The circuit and the method can be used
in a contactless chip card.