米6体育平台手机版

ZHCSOA0 November 2022 OPA4H199-SEP

PRODUCTION DATA

封装选项

机械数据 (封装 | 引脚)

DYY|14
- MPSS114C

散热焊盘机械数据 (封装 | 引脚)

订购信息

zhcsoa0_oa

8.2.1.2 Detailed Design Procedure

The transfer function of the circuit in Figure 8-1 is given in Equation 1.

Equation 1. V_OUT = I_LOAD × R_SHUNT × Gain

The load current (I_LOAD) produces a voltage drop across the shunt resistor (R_SHUNT). The load current is set from 0 A to 1 A. To keep the shunt voltage below 100 mV at maximum load current, the largest shunt resistor is defined using Equation 2.

Equation 2.

R_{S H U N T} = \frac{V_{S H U N T_M A X}}{I_{L O A D_M A X}} = \frac{100 m V}{1 A} = 100 m Ω

Using Equation 2, R_SHUNT is calculated to be 100 mΩ. The voltage drop produced by I_LOAD and R_SHUNT is amplified by the OPA4H199-SEP to produce an output voltage of 0 V to 4.9 V. The gain needed by the OPA4H199-SEP to produce the necessary output voltage is calculated using Equation 3.

Equation 3.

G a i n = \frac{{(V}_{O U T_M A X} - V_{O U T_{M I N}})}{(V_{I N_M A X} - V_{I N_M I N})}

Using Equation 3, the required gain is calculated to be 49 V/V, which is set with resistors R_F and R_G. Equation 4 is used to size the resistors, R_F and R_G, to set the gain of the OPA4H199-SEP to 49 V/V.

Equation 4.

G a i n = 1 + \frac{(R_{F})}{(R_{G})}

Choosing R_F as 360 kΩ, R_G is calculated to be 7.5 kΩ. R_F and R_G were chosen as 360 kΩ and 7.5 kΩ because they are standard value resistors that create a 49:1 ratio. Other resistors that create a 49:1 ratio can also be used. Figure 8-2 shows the measured transfer function of the circuit shown in Figure 8-1.