Design of High Efficiency Green Mode SMPS Regulator

The better efficiency means less heat dissipation and longer battery lifetime in wireless communication products and other portable systems powered by batteries. Therefore, the power management system with high efficiency is of great importance. As a solution, a green mode SMPS (switch mode power supply) buck regulator is proposed in this paper. Its efficiency is enhanced by so called multi-mode operation, witch controls the regulator to operate in PWM (pulse width modulation) mode under heavy or medium loads and in burst mode under light load. In addition, the use of internal synchronous rectifier is also beneficial to increase of the efficiency. Some new functions including on-chip current sensing technique and over voltage suppression have been introduced into the control strategy. Simulation results show that all expected performances are successfully achieved. The regulator is designed and fabricated in 1.5-mum BCD (Bipolar-CMOS-DMOS) technology with the area of 6.5 mm².