A converter includes a control chip, a switching transistor, a step-down circuit and a linear power circuit. The control chip is configured to: convert an input voltage from an external power supply module into a control voltage; when a bootstrap voltage is received, convert the bootstrap voltage into the control voltage and stop converting the input voltage; and control the switching transistor to be periodically turned on and off based on the control voltage to cause the power supply module to periodically output the input voltage to the step-down circuit. The step-down circuit is configured to generate an operating voltage based on the input voltage and outputs the operating voltage to an electrical unit and the linear power circuit. The linear power circuit is configured to convert the operating voltage into the bootstrap voltage and output the bootstrap voltage to the control chip.