8.2.2 Detailed Design Procedure

To achieve bidirectional monitoring, drive the reference pin halfway between the supply with a resistor divider buffered by an op amp, as shown in Table 5. To reduce the current draw from the supply, use 100-kΩ resistors to create the divide-by-two voltage divider. The TLV313-Q1 is selected to buffer the voltage divider because this device can operate from a single-supply rail with low I_Q and offset voltage. To minimize the response time of the ALERT2 output, a 100-kΩ pullup resistor was added from the DELAY pin to the VS pin. Select values for R_SENSE, R_LIMIT2, and R_LIMIT1 based on the desired current-sense levels and trip thresholds using the information in the Resistor-Controlled Current Limit and Selecting a Current-Sensing Resistor (RSENSE) sections. For this example, the values of R_LIMIT1 and R_LIMIT2 were selected so that the positive and negative overcurrent thresholds are the same. Table 5 shows the alert output of the INA303 application circuit with the capability to detect both positive and negative overcurrent conditions.