V o = − V i × R 1 R 2 − V r e f × ( R 1 R 3 ) Vo = − Vi × \frac{R1}{R2} − Vref × (\frac{R1}{R3}) Vo=−Vi×R2R1−Vref×(R3R1)
计算输入信号的增益。 G i n p u t = V o m a x − V o m i n V i m a x − V i m i n = 3.3 V − 0.05 V − 1 V − ( − 5 V ) = 0.8125 V V Ginput = \frac{V_{omax} − V_{omin}}{V_{imax} − V_{imin}} = \frac{3. 3V − 0. 05V}{−1V −( −5 V)} =0 . 8125 \frac{V}{V} Ginput=Vimax−ViminVomax−Vomin=−1V−(−5V)3.3V−0.05V=0.8125VV
计算 R1 和 R2。 C h o o s e R 1 = 845 Ω Choose R1 =845Ω ChooseR1=845Ω R 2 = R 1 G i n p u t = R 1 0.8125 V V = 1.04 k Ω R2 = \frac {R1}{G_{input}} = \frac {R1}{0. 8125 \frac{V}{V}}=1 . 04 kΩ R2=GinputR1=0.8125VVR1=1.04kΩ
计算抵消输出所需的基准电压增益。 G r e f = R 1 R 3 Gref = \frac {R1}{R3} Gref=R3R1 − V i m i n × R 1 R 2 − V r e f × R 1 R 3 = V o m i n − V_{imin} × \frac{R1}{R2} − Vref × \frac{R1}{R3} =V_{omin} −Vimin×R2R1−Vref×R3R1=Vomin R 1 R 3 = V o m i n + V i m i n × R 1 R 2 − V r e f = 0.05 V + ( − 1 V ) 845 Ω 1.04 k Ω − 5 = 0.1525 V V \frac {R1}{R3} = \frac { V_{omin} +V_{imin} × \frac {R1}{ R2} }{ −Vref}= \frac {0. 05V +( −1 V) \frac{ 845Ω }{1. 04kΩ} }{−5} =0 . 1525 \frac{V}{V} R3R1=−VrefVomin+Vimin×R2R1=−50.05V+(−1V)1.04kΩ845Ω=0.1525VV
计算 R3。 R 3 = R 1 G r e f = 845 Ω 0.1525 V V = 5.54 k Ω ≈ 5.56 k Ω R3 = \frac{R1}{Gref }= \frac{845Ω}{0.1525 \frac {V}{V}} =5 . 54 kΩ ≈ 5. 56 kΩ R3=GrefR1=0.1525VV845Ω=5.54kΩ≈5.56kΩ