CIRCUIT060035

This bidirectional current sensing solution uses a current-sense amplifier and a high-speed dual comparator with a rail-to-rail input common mode range to create over-current (OC) alert signals at the comparator outputs (OUTA and OUTB) if the input current (IG1) rises above 100 A or falls below -35 A. In this implementation, both over-current alert signals are active high, so when the 100 A or -35 A thresholds are crossed, the comparator outputs will go high. External hysteresis is implemented on both comparators so that the comparator outputs will return to logic low states when the current reduces by 10% (90 A and -31 A). While the circuit below has shunt resistor R8 connected to ground, the same circuit is applicable for high side current sensing up to the common mode voltage range of the INA.

System current levels:

• Falling OC threshold : IG1 < -35 A
• Falling OC recovery: IG1 > -31 A
• Rising OC threshold: IG1 > 100 A
• Rising OC recovery: IG1 < 90 A

Supply:

• V+ = 3.3 V
• V- = 0 V