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ADS1220电阻桥测量电路的输入及参考电压问题

衡祐
Intellectual 363 points
Other Parts Discussed in Thread: ADS1220

依据手册手册上典型应用，将REFP1和REFN1作为基准电压，依据下图搭建电路，参考电压设置为模拟电源3,3V，设置好参考电压以后，电阻桥输出大概0.145v（在电阻桥上加载3.3V电源，输出实际应该为0.8mV），但是AIN1和AIN2引脚压差到了2.045V请问这是何原因？

采样温度时如图：设置REFP0及REFN0为参考电压输入，电流输出设置为100uA，参考电压大概应该为1.5V左右，但是每次参考电压都不稳定，REFP0及REFN0间压差达到2.6V，这是什么原因？

请问有什么方法可以判断ADS1220芯片的好坏？

  • 0
    Guru 63421 points

    如果是内部基准, 那么内部的是 2.048V 基准电压

    关于内部的这个开关, 看手册的说明

    8.3.9 Low-Side Power Switch
    A low-side power switch with low on-resistance connected between the analog input AIN3/REFN1 and AVSS is integrated in the device as well. This power switch can be used to reduce system power consumption in bridge sensor applications by powering down the bridge circuit between conversions. When the respective bit (PSW) in the configuration register is set, the switch automatically closes when the START/SYNC command is sent and opens when the POWERDOWN command is issued. Note that the switch stays closed between conversions in  single-shot mode in case the PSW bit is set to 1. The switch can be opened at any time by setting the PSW bit to 0. By default, the switch is always open.

  • 0 回复 user151383853
    Intellectual 363 points

    Airwill 说：

    如果是内部基准, 那么内部的是 2.048V 基准电压

    关于内部的这个开关, 看手册的说明

    8.3.9 Low-Side Power Switch
    A low-side power switch with low on-resistance connected between the analog input AIN3/REFN1 and AVSS is integrated in the device as well. This power switch can be used to reduce system power consumption in bridge sensor applications by powering down the bridge circuit between conversions. When the respective bit (PSW) in the configuration register is set, the switch automatically closes when the START/SYNC command is sent and opens when the POWERDOWN command is issued. Note that the switch stays closed between conversions in  single-shot mode in case the PSW bit is set to 1. The switch can be opened at any time by setting the PSW bit to 0. By default, the switch is always open.

    看资料时忽略了这个控制位，感谢楼上大神