基于MSP430的低功耗流量计

针对某些应用场合由于没有外部电源供电或使用导线引用电源费用较高的问题,文中设计了基于MSP430F149的低功耗流量计,主要完成了流量计的硬、软件的低功耗设计。系统电源设计为两级转换,第一级转换过程,根据压降型DC/DC与LDO在不同情况下转换效率各有优劣,故设计了逻辑判断选择电路。第二级转换过程,利用LDO降低模拟部分供电电压,节省了功耗;此外,系统的温度和压力补偿模块,则采用间歇采样模式。在采样间隙,利用单刀双掷从电压上位端切断恒流源供给,从而降低了系统功耗。通过上述措施,使得系统平均电流为470 μA,符合电池供电的设计要求

Low Power Flow-meter Based on MSP430

A low power loss flow-meter is designed based on the MSP430F149 to cope with the high electricity expense caused by the lack of the external power supply or by the use of wires. Both hardware and software designs are presented. The system power source adopts two levels conversion： a logical judgment selecting circuit is designed for the primary conversion, as the pressure drop DC/DC and LDO have their respective advantages in transfer effi- ciency under different conditions; in the secondary conversion, LDO is used to lower the power line voltage of the simulation part so as to save the power loss. The system temperature and the pressure compensation modules adopt the intermittent sampling pattern, which cuts off constant current supplies in the sampling gaps from the upper volt- age end using SPDT （ single pool double throw）, thus reducing the system power loss. The system mean current re- duces to 470μA, which meets the battery power supply design requirement.