A voltage converter includes a first switching element, a second switching element, and a forced maintaining circuit. The first switching element is configured to operate based on a switching control signal. The second switching element is connected to the first switching element. The second switching element is configured to operate based on the switching control signal in a synchronous mode and operate in a diode mode in an asynchronous mode. The forced maintaining circuit is connected to the second switching element and configured to maintain the asynchronous mode for a forced maintaining period after entering the asynchronous mode.