Design Of Key Circuits Of BOOST Converter

In recent years, as a result of widely using portable equipments, there are more requirements to power supply. The service life of Battery-powered equipment is required as long as possible, so we must improve efficiency of power supply. Because of the internal modulate transistor of SMSP (Switch Mode Power Supply) in switch mode operating at a high frequency, its equivalent impedance is very small and consumes very little energy;that the power efficiency can reach 70% ~ 90%, nearly double that of normal linear regulator . Therefore it represents the orientation of steady voltage supply, and becomes the staple product. Nowadays, foreign enterprises almost occupy the whole market of power management IC, so it is necessary to develop the power management ICs with own intellectual property.After fully analyzing the associated knowledge and circuit structure of DC-DC power IC, two circuits named bandgap reference voltage circuits and current limited circuits are implemented with 0.5um BICMOS process. They both can be used in the BOOST Converter which using the control techniques of Current-limited Minimum-off-time PFM. The research produce is supported by National Science Foundation of China and Sichuan Province Academic and Technologic Leaders Foundation.The basic principle of monolithic switching regulator is narrated at first. Then, focus on the BOOST Converter which using the control techniques of Current-limited Minimum-off-time PFM. According to the topology of the chip, the author designed the key sub-circuit blocks of the chip, such as: bandgap reference voltage circuits and current limited circuitsBased on the principle analysis and circuit design in the first part, the author simulated all sub-circuits and the whole chip circuit using EDA tools HSPICE, the simulation result indicates that the IC has achieved the expectation, both function target and electrical characteristics.