Design Of Low Voltage Start-up Boost DC-DC Converter Based On Hysteresis Current Mode Control

The rapid development of integrated circuit technology has led to the prosperity and development of consumer electronic equipment.In the context of the continuous updating of microelectronics manufacturing processes and switching power supply topologies,Boost DC-DC converters,as one of the stable and efficient power supply units for load terminals,are evolving towards lower power consumption,higher integration,more features and higher conversion efficiency.The current portable electronic products require Boost DC-DC converters to be able to start and operate normally under low-voltage power supply,and it is required to output a wide range of load power.This article designs a Boost DC-DC converter that can meet low-voltage startup and has a wide range of input voltage and output voltage.The converter can provide an output load current of 1m A to 500 m A.The converter is based on the topological structure of hysteresis current mode control,and generates a relatively constant inductor current ripple through a fixed hysteresis voltage window to track the change of the average inductor current,thereby stably regulating the output voltage.The current feedback inner loop composed of the full-period inductor current sampling circuit and the voltage feedback outer loop composed of the error amplifier form a dual-loop control,which improves the system loop response speed.The complete loop of the system formed by the current and voltage feedback double loop and the hysteresis comparator,relying on the inherent self-stability of the hysteresis voltage window without the need for an additional oscillator to provide slope compensation,thus simplifies the design of the system loop.The converter uses part of the low-threshold CMOS process devices,combined with the logic multiplexing function of the drive circuit,to achieve a low-voltage startup of 0.7V.The automatic mode switching function under light load and heavy load conditions ensures that the converter can maintain a high conversion efficiency when outputting a wide range of load currents.This design is based on the TSMC 0.18μm CMOS process to simulate and test the overall function of the converter system.The simulation results show that the converter can achieve a low-voltage startup of 1.55 ms under the condition of 0.7V input boost to5 V output,and under this condition,it can provide a maximum stable output current of90 m A and maintain a conversion efficiency of 76%.In addition,the conversion efficiency reaches more than 90%,when the converter provides a load current ranging from 10 m A to 500 m A,under the condition that the input voltage is 3V and the output voltage is 4V and 5V respectively.