| With the rapid development of integrated circuit technology,the position of the power management chip in the electronic system is more and more important.Because for any electronic product with a load,whether it is a mobile phone,a tablet,a wearable device,or a vehicle electronic,it cannot work normally without stable power supply.As a branch of the power management chip,the DC-DC converter has become the most important role in the power chip market with its advantages of high efficiency,low cost,and wide application range.In this context,this paper studies a low-power isolated DC-DC power controller.The isolated DC-DC module adopts push-pull topology and full-wave rectification,and the output power is 1W.It is mainly used for point-of-use power conversion,digital interface power,ground loop elimination and power-supply noise reduction.The two switch power mos in the push-pull converter are alternately conducting,so that the transformer core is alternately magnetized and the utilization of the magnetic core is improved,but the bias magnetic easily leads to device damage.In order to prevent bias magnetic.It uses the UVLO module to detect the internal voltage source and the reference detection module to detect reference voltage.When the internal power supply voltage reaches the threshold and the reference voltage is stabilized,the oscillator is enabled to ensure that the oscillator is stable when it starts to oscillate.The power mos driver module is added with delay capacitors for adjusting the dead time and can be processed through the FIB to ensure that the conduction time of the two power mos are basically the same.A trimming circuit is added to the current bias module to ensure that the oscillator frequency is within the index range;An over-temperature protection module is designed and the over-temperature-protection temperature is 150℃,exit-protection temperature is 130℃.The chip adopts 0.35μm BCD process,and after layout design and tapeout verification,the test results meet the parameters of the controller chip.For the DC-DC module when the load current is switched between no load(0A)and full load(200mA)at the slope of 255mA/μs,the overshoot is 54 mV and undershoot is 80 mV. |
