Abstract: Chip transformer is an air-core transformer made on silicon wafer,which has high coupling coefficient,low power consumption and integratability.Traditional isolation communication design using discrete component which cannot be facilitate integration,while an isolator design based on the chip transformer has obvious advantages than traditional isolation instruments in power consumption,volume,transmission rate and has a broad prospect of application.According to the chip transformer,digital signal is transmitted in high-speed pulse form.When there is no voltage jump,refresh circuit will give refresh impulse periodically to correct dc potential,and this is very important on under these conditions of power-up state,lower data rate input waveform and constant dc input.