In this paper,the application of neural network to power converter control is discussed.A new hysteresis comparator constructed by using neural network is introduced.Hysteresis band control is an effective and simple control method.It can easily run without many system parameters.But the switch frequency of system is not fixed.So it not only makes the system unstable but also may lessen the life span of the switches. The control method that combines the neural network technology with the hysteresis band technology has a high performance in response of current.Through training the neural network can learn the control rules by itself and can replace the real hysteresis comparator in power converter control.The computer simulation results are given in this paper and they can demonstrate the effectiveness of the proposed method.The neural network is realized by using DSP.