一种高精度CMOS库仑计的设计

Design of a High Accuracy CMOS Coulomb Meter

针对移动电子设备对锂电池库仑计的特殊要求,基于上华0.5μm工艺,设计了一种电源电压范围为2.9~4.3V的CMOS库仑计。在电阻串实现分压方面,采用了短接到地和直接选择相结合的方法,使得分压精度更加线性化,能够实时、准确地反映电量。比较器方面,在两相不交叠时钟的控制下,将电阻分压后的电池电压由高到低逐次进行比较,可抵消失调。最终电池放电测试结果表明,测试结果与理论相符。

In order to meet the special requirements of lithium battery coulomb meter on mobile electronic devices,a CMOS coulomb meter with a supply voltage range from 2.9Vto 4.3Vwas designed based on the CSMC0.5μm process.Voltage dividing of the resistor string was achieved through the shorted to ground method combined with the directly selection method.The voltage dividing accuracy was more linear,and the electric quantity could be measured accurately in real time.After divided by resistors,the battery voltage was compared successively in descending order by the comparators under the control of the two-phase non-overlapping clocks,so the offset was cancelled.The discharging of the battery had been tested,and the results showed that the test values corresponded to the theoretical values.