8.2.3 Application Curves

Figure 8-2 and Figure 8-3 show the ALERT pin response to an overcurrent fault with a conversion time of 50 μs

for the temperature, shunt voltage, and bus voltage measurements with averaging set to 1. This configuration

results in a total conversion time of 150 μs for all three measurements. For these scope shots, persistence was

enabled on the ALERT channel to show the variation in the alert response for many sequential fault events. The

alert response time can change depending on the value of the current before fault occurs as well as the how

much the fault condition exceeds the programmed fault threshold. Figure 8-2 shows the response time for an

overcurrent fault when the fault condition greatly exceeds the programmed threshold. While Figure 8-3 shows

the overcurrent response time when the fault slightly exceeds the programmed threshold. Variation in the alert

response exists because the external fault event is not synchronized to the internal ADC conversion start. Also

the ADC is constantly sampling to get a result, so the response time for fault events starting from zero will be

slower than fault events starting from values near the set fault threshold. In applications where the alert timing is

critical for overcurrent events, the worst-case alert response is equal to 2 × tconv_current + tconv_temp + tconv_voltage +

25 μs. An additional 25 μs is added to allow for background math calculations.

Minimum Delay: 35.38 µs

TIME (50µs / div)

Fault Threshold: 100 mA

Maximum Delay: 186.4 µs

Figure 8-2. Alert Response Time (Sampled Values

Significantly Above Threshold)

Minimum Delay: 63.90 µs

TIME (50µs / div)

Fault Threshold: 400 mA

Maximum Delay: 212.9 µs

Figure 8-3. Alert Response Time (Sampled Values

Slightly Above Threshold)

www.ti.com

INA700

SBOSAB4A – MAY 2023 – REVISED SEPTEMBER 2023

Copyright © 2023 Texas Instruments Incorporated

Submit Document Feedback

37

Product Folder Links: INA700