A data processing device based on a programmable logic device is described that includes at least one function circuit configured to process input data; and at least one current smoothing circuit, each corresponding to one of the at least one function circuit, and configured to smooth a current change of the programmable logic device caused when a corresponding function circuit is switched between on and off. The current smoothing circuit includes a control circuit configured to generate a driving signal based on a switching manner of the function circuit corresponding to the current smoothing circuit; and a redundant circuit configured to operate according to the driving signal to smooth the current change. The control circuit includes a decoding control word generating circuit and a decoding circuit.