The Output Can Be Adjusted To The High Efficiency Vacuum Dc / Dc Controller Ic Design

As the growing of the consumer's electronic market, the trend of minimization of the portable consumer's electronic product is continually dominating the industry. However, the realization of the multifunction and long standby in some products is the new challenge for the industry. As the result, power management module with high efficiency is the indispensable part in the electronic design. The monolithic switch power IC possesses the high efficiency, simple external circuit and small output ripple, which is suitable for the portable application.Following to the application requirement of the portable device, a monolithic negative DC-DC converter with tunable output voltage is propose in this paper. The IC exhibits the high operation frequency, high efficiency and wide input/output voltage range, additionally, the power MOSFET is internally integrated, which requires only a few external parts for the complete power system. The integrated power MOSFET current limiter and output voltage protection block guarantee the reliable operation of the system.The system is designed to operate at PWM mode under heavy load and two optional operation modes at light load. One is PSM mode, which allows the high efficiency operation of the system but will cause large output ripple; the other is Force PWM mode, which will generate small output ripple while trade off the efficiency. To further boost the efficiency, the split buffer is adopted to prevent the direct energy loss path, which effectively cut the energy loss.The BUCK-BOOST topology and voltage mode feedback is adopted in the system architecture to generate the negative output and build the feedback loop. Combined with the voltage feedforward technology, the system allows better line regulation and larger input voltage range. The lead compensation is utilized in the system to enhance the system loop stability and widen the loop bandwidth. Additionally, the system output accuracy is only limited to the error of the voltage reference and the offset of error amplifier.The circuit is verified by Synosys Hspice simulator based on UMC 0.5um standard CMOS process with the power MOSFET. The results indicates the design specification is satisfied and the efficiency is up to 87.5%, the corner simulation demonstrate that the design is insensitive to the process variation.