基于NMOS功率管的Buck-Boost效率提升方法

Buck-Boost Efficiency Improvement Method Based on NMOS Power Transistor

为使有源矩阵有机发光二极管(AMOLED)显示器最大限度的节省电源消耗,延长电池寿命,传统的P型金属氧化物半导体(PMOS)功率管需要较大的面积来减小开关损耗。针对上述问题,提出了基于N型金属氧化物半导体(NMOS)功率管的Buck-Boost转换结构,与同等宽长比的PMOS相比,NMOS作为功率管大幅降低了开关管的导通损耗,提升了系统转换效率;同时设计了一种恒定的NMOS功率管栅极驱动电路,保证功率管充分导通。采用所提结构实现了一款峰值电流模脉宽调制(PWM)控制的Buck-Boost型DC/DC转换器,验证结果显示输入电压为3.7 V,输出电压为-4 V,负载电流在35~200 mA范围内,转换效率维持在91%以上,为高效AMOLED的显示技术提供了有效的解决方案。

In order for active-matrix organic light-emitting diode(AMOLED)displays to save power consumption to the utmost extent and extend battery life,traditional P type metal oxide semiconductor(PMOS)power tubes require a larger area to reduce switching losses.In response to the above problems,a Buck-Boost conversion structure based on N type metal oxide semiconductor(NMOS)power tubes is proposed.Compared with PMOS with the same aspect ratio,NMOS as a power tube greatly reduces the conduction loss of the switch tube and improves the conversion efficiency of the system.A constant NMOS power transistor gate drive circuit is designed to ensure that the power transistor is fully turned on.Using the proposed structure,a Buck-Boost DC/DC converter controlled by peak current mode pulse width modulation(PWM)control is implemented.The verification results show that the input voltage is 3.7 V,the output voltage is-4 V,the load current is within the range of 35~200 mA,and the conversion efficiency is maintained above 91 %,which provides an effective solution for high efficiency AMOLED display technology.