7.3.3.1.1.1 Resistor-Controlled Current Limit: Example

For example, if the current level indicating an out-of-range condition (I_TRIP) is 20 A and the current-sense resistor value (R_SENSE) is 10 mΩ, then the input threshold signal is 200 mV. The INA302A1 has a gain of 20, so the resulting output voltage at the 20-A input condition is 4 V at the output of the current-sense amplifier when the REF pin is grounded. The value for R_LIMIT is selected to allow the device to detect this 20-A threshold, indicating that an overcurrent event has occurred. When the INA302 detects this out-of-range condition, the ALERTx pin asserts and pulls low. For this example, the value of R_LIMIT to detect a 4-V level is calculated to be 50 kΩ.