A voltage converter includes a transformer circuit, a filter, and a
controller. The transformer circuit is coupled to the filter, and the
controller is coupled to the transformer circuit and the filter. The
transformer circuit includes an input port and an autotransformer coupled
to the input port. The voltage converter receives an input signal at the
input port and generates a transformer output signal from a transformer
output port. The filter receives the transformer output signal on a
filter input port and the filter generates an output signal at an output
port. The controller receives the output signal from the filter and
provides one or more control signals to the transformer circuit to
control the output signal. A method includes receiving a first input
signal on an input port at a transformer circuit including a first coil
and a second coil, activating a first switch to serially connect the
first coil to the second coil, activating a second switch to connect the
second coil to a second input port, deactivating the first switch and the
second switch, and activating a third switch to connect the first input
signal to the second input port.