A digital power supply circuit and a liquid crystal driving device are provided. The digital power supply circuit includes a controlling module which includes an acquiring unit for acquiring a rate of change of the digital supply voltage at an initial stage, a comparing unit for comparing the rate of change with a preset threshold value, so as to generate a control signal according to the comparing result, and a voltage reducing unit for pulling-down an input voltage of the enable terminal by using the control signal when the rate of change is greater than the preset threshold value.