SBOSAJ3 June 2024 TLV9104-Q1
PRODMIX
Use Equation 1 to calculate the transfer function of the circuit in Figure 7-1.
The load current (ILOAD) produces a voltage drop across the shunt resistor (RSHUNT). The load current is set from 0A to 1A. To keep the shunt voltage below 100mV at maximum load current, use Equation 2 to calculate the largest shunt resistor allowed.
Using Equation 2, RSHUNT is calculated to be 100mΩ. The voltage drop produced by ILOAD and RSHUNT is amplified by the TLV910x-Q1 to produce an output voltage of 0V to 4.9V. Use Equation 3 to calculate the gain required for the TLV910x-Q1 to produce the necessary output voltage is calculated using.
Equation 3 calculates the required gain as 49V/V, which is set with resistors RF and RG. Equation 4 is used to size the resistors, RF and RG, to set the gain of the TLV910x-Q1 to 49V/V.
With RF as 360kΩ, Equation 4 calculates RG as 7.5kΩ. This example has the RF and RG as 360kΩ and 7.5kΩ because these values are the standard resistor values that create a 49:1 ratio. Other resistors that create a 49:1 ratio can also be used. Figure 7-2 shows the measured transfer function of the circuit shown in Figure 7-1.