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AD74412R 在CURRENT INPUT EXTERNALLY POWERED模式下adc值异常

ad74412r的其他模式下,工作正常,adc值读取符合预期。

但是在CURRENT INPUT EXTERNALLY POWERED模式下adc值异常,当外接电源输出1-4ma时(即ad74412r输入电流为1-4ma时),读取的adc值的范围0x300至0xcb00。

当然后增大电流时,adc又从0x1000上升到0xcb00范围。

输入电流:2ma adc code:0x3a92
输入电流:3ma adc code:0x72c0
输入电流:4ma adc code:0xa8ba
输入电流:4ma adc code:0xa955
输入电流:5ma adc code:0xcf2b
输入电流:5ma adc code:0xcf2b
输入电流:6ma adc code:0xf546
输入电流:7ma adc code:0x6557
输入电流:8ma adc code:0x33c5
输入电流:9ma adc code:0x30ad
输入电流:10ma adc code:0x2cec
输入电流:11ma adc code:0x1e21

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  • Hi,

    would it be possible to know more about your setup? 

    What is exactly is connected as current input at this channel? What is the value of the ADC_CONFIGx register for the channel you are using in this setup?  

    Regards,

    Arnost


  •                                                                             I/OP_x and I/ON_x voltage     Rsense voltage
    input current 1ma, adc code:6753 (decimalism)            0.9v                                  0.1v
    input current 2ma, adc code:20161
    input current 3ma, adc code:44071
    input current 4ma, adc code:54154
    input current 4.5ma, adc code:59038
    input current 5ma, adc code:60497                               1.44v                              0.5v
    input current 6ma, adc code:12454
    input current 7ma, adc code:9995
    input current 8ma, adc code:5737
    input current 9ma, adc code:126
    input current 10ma, adc code:0                                        2.3v                              1v
    input current 11ma, adc code:0                                         2.47                            1.1v
    input current 12ma, adc code:1251
    input current 13ma, adc code:34076
    input current 14ma, adc code:36696
    input current 15ma, adc code:39315
    input current 16ma, adc code:41937
    input current 17ma, adc code:44568
    input current 18ma, adc code:47189
    input current 19ma, adc code:49812
    input current 20ma, adc code:52434                            4v                                       2v

    The voltages of terminals I/OP_x and I/ON_x increase monotonically.
    The voltage across the sampling resistor also increases monotonically.
    The voltage of the sampling resistor is as expected

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  •                                                                             I/OP_x and I/ON_x voltage     Rsense voltage
    input current 1ma, adc code:6753 (decimalism)            0.9v                                  0.1v
    input current 2ma, adc code:20161
    input current 3ma, adc code:44071
    input current 4ma, adc code:54154
    input current 4.5ma, adc code:59038
    input current 5ma, adc code:60497                               1.44v                              0.5v
    input current 6ma, adc code:12454
    input current 7ma, adc code:9995
    input current 8ma, adc code:5737
    input current 9ma, adc code:126
    input current 10ma, adc code:0                                        2.3v                              1v
    input current 11ma, adc code:0                                         2.47                            1.1v
    input current 12ma, adc code:1251
    input current 13ma, adc code:34076
    input current 14ma, adc code:36696
    input current 15ma, adc code:39315
    input current 16ma, adc code:41937
    input current 17ma, adc code:44568
    input current 18ma, adc code:47189
    input current 19ma, adc code:49812
    input current 20ma, adc code:52434                            4v                                       2v

    The voltages of terminals I/OP_x and I/ON_x increase monotonically.
    The voltage across the sampling resistor also increases monotonically.
    The voltage of the sampling resistor is as expected

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