Research On Key Technologies Of Smart Charge Chip Used For Bluetooth Headset Charge Bin.

With the widespread promotion of various types of wearable devices,electronic products with low power consumption requirements have gradually increased.Therefore,how to reduce the power consumption of switching power management IC has become a hot research area.The switching power management IC with high integration and low power consumption has high theoretical and commercial value.In this paper,the small signal model of peak current mode and voltage mode is established,the transfer function is derived,and the compensation circuit is designed according to the zeros and poles.The small signal model is calculated and the bode plot is drawn by using Matchcad.Then,the working principle of the bandgap reference is analyzed in detail,and a low-power bandgap reference is designed.In this paper,NU 0.35 μ m BCD process is used for circuit design.The simulation results show that when the chip is in the Boost mode,it can achieve the Boost function from1.8V to 4.3v input voltage,the maximum output voltage is 5V,and the maximum peak load is 1A;When the chip is in Buck mode,4v-5.5v input pair can be realized to realize the lithium battery charging function,and the maximum duty cycle can reach100% in Buck mode.Under light load,the power consumption is only 8 μ a,which meets the expected design index and has a good application prospect.