This paper introduces a digital multi-mode boost converter with wide range of input voltage for an energy recycling load system. The boost converter is controlled digitally with constant off-time/constant frequency hybrid pulse width modulation (PWM) control. Constant off-time control is to avoid the limit cycle oscillation and gain a high gain when the input voltage is far less than the output voltage. Otherwise, constant frequency PWM is adopted. Finally, a 3.6 kW DC/DC boost converter with twelve 300 W channels in parallel was built for an energy recycling load system and the experimental results testify it to get high gain up to 49 and high efficiency up to about 98%.