A rapid shutdown (RSD) control circuit includes: a RSD controller having first and second terminals coupled to first and second terminals of a photovoltaic cell module, respectively; a transistor having a gate coupled to the RSD controller, a source coupled to the second terminal of the photovoltaic cell module, and a drain; and a diode coupled between the drain of the transistor and the first terminal of the photovoltaic cell module. In a normal state, controlled by the RSD controller, the transistor is controlled to have a first impedance state and the photovoltaic cell module outputs an output power to an inverter. In a shutdown state, controlled by the RSD controller, the transistor and the diode are controlled as a variable impedance, and thus a voltage between the first terminal and the second terminal of the photovoltaic cell module is regulated to a desired voltage.