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.