An exemplary voltage converter includes a pulse width modulation controller chip, a pull-up transistor, a pull-down transistor, and a low pass filter. The pulse width modulation controller chip includes a plurality of pins, a gate control logic circuit, a first gate driver, a second gate driver, a current source, a first resistor, a first comparator, and a power-on reset circuit. The plurality of pins include a Vcc pin connected to a chip power supply, a BOOT pin connected to the Vcc pin via a first zener diode for receiving power from the chip power supply, a PHASE pin connected to the BOOT pin via a capacitor, a UGATE pin, a LGATE pin, and a GND pin that is grounded. The PHASE pin serves as a multi-function pin in the pulse width modulation controller chip.