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PGA280设置问题,求助

Other Parts Discussed in Thread: PGA280

之前发贴:http://www.deyisupport.com/question_answer/analog/amplifiers/f/52/t/105669.aspx

现在问题是将输入设置为INP1+INN1或是INP2+INN2(电路上,两种方法刚好反相,即同一个输入信号V+,V-,使用IN1时,INP1接V+,INN1接V-,使用IN2时,INP2接V-,INN2接V+),

设置各种GAIN时无反应,

:V+ - V- = 100mV ;  无反应是指:输出一直等于Vcom

但设置成INP1+INN接地  或INN1+INP接地  ..等,只要INN/INP/N/P单端输入时,设置不同的GAIN,输出都会相应比例变化,  COM接2.5V   VSOP是5.2V  VSP+15V,VSN-15V

  • #define GPA280_PRA_SW1_A1            0x40
    #define GPA280_PRA_SW1_A2            0x20
    #define GPA280_PRA_SW1_B1            0x10
    #define GPA280_PRA_SW1_B2            0x08
    #define GPA280_PRA_SW1_C1            0x04
    #define GPA280_PRA_SW1_C2            0x02
    #define GPA280_PRA_SW1_D12          0x01
    #define GPA280_PRA_SW2_F1             0x08
    #define GPA280_PRA_SW2_F2             0x04
    #define GPA280_PRA_SW2_G1            0x02
    #define GPA280_PRA_SW2_G2            0x01

    #define GPA280_SW1_SEL_INP1         GPA280_PRA_SW1_A1 //单连接 1+
    #define GPA280_SW1_SEL_INN1         GPA280_PRA_SW1_A2 //单连接 1-
    #define GPA280_SW1_SEL_IN1            (GPA280_PRA_SW1_A1 | GPA280_PRA_SW1_A2) //使用 1+-
    #define GPA280_SW1_SEL_INP2         GPA280_PRA_SW1_B1 //单连接 2+
    #define GPA280_SW1_SEL_INN2         GPA280_PRA_SW1_B2 //单连接 2-
    #define GPA280_SW1_SEL_IN2            (GPA280_PRA_SW1_B1 | GPA280_PRA_SW1_B2) //使用 2+-
    #define GPA280_SW1_SEL_SHORT_IN1                 GPA280_PRA_SW1_D12 //短路 1+ 1-输入
    #define GPA280_SW2_SEL_INP1_TO_GND            GPA280_PRA_SW2_G1 //1+ 短地
    #define GPA280_SW2_SEL_INN1_TO_GND            GPA280_PRA_SW2_G2 //1- 短地
    #define GPA280_SW1_SEL_P_TO_GND                   GPA280_PRA_SW1_C1 //+短地
    #define GPA280_SW1_SEL_N_TO_GND                   GPA280_PRA_SW1_C2 //-短地
    #define GPA280_SW1_SEL_SHORT_P_N                 (GPA280_SW1_SEL_IN1 | GPA280_PRA_SW1_D12) //使用 1+-, 且1+短1-
    #define GPA280_SW2_SEL_INP1_UP_100UA          GPA280_PRA_SW2_F1 //上拉恒流
    #define GPA280_SW2_SEL_INN1_DN_100UA          GPA280_PRA_SW2_F2 //下拉恒流

    #define GPA280_SW_OPEN                                            0x00

    PGA280_Init();

    PGA280_SW_A_D(GPA280_SW1_SEL_IN1);    

    //PGA280_SW_A_D(GPA280_SW1_SEL_INP1  |  GPA280_SW1_SEL_N_TO_GND);

    PGA280_SW_F_G(GPA280_SW_OPEN);

    //0~10表示GAIN=1/8~128

    PGA280_Gain_Set(0);
    PGA280_Gain_Set(1);
    PGA280_Gain_Set(2);
    PGA280_Gain_Set(3);
    PGA280_Gain_Set(4);
    PGA280_Gain_Set(5);
    PGA280_Gain_Set(6);
    PGA280_Gain_Set(7);
    PGA280_Gain_Set(8);
    PGA280_Gain_Set(9);
    PGA280_Gain_Set(10);