Supervisor IC Eliminates Low Battery Chatter

A highly flexible voltage supervisor IC that detects low battery conditions, MIC2778 features adjustable hysteresis and ultra-low quiescent current. Unlike most voltage supervisor ICs that combine power supply and input monitoring to offer only small fixed amounts of hysteresis, MIC2778 trip-points and hysteresis are adjusted with external resistors to let users set any voltage trip-point for any amount of hysteresis. Most battery-powered systems disconnect the battery from the load when it discharges to a set level. With the load removed, the battery voltage recovers somewhat, which makes the system detect a good battery voltage and load is re-established. This causes the system to chatter around the low voltage point because sufficient hysteresis is not established for full operation. The optimal settings cannot be determined without extensive field testing of the system. The MIC2778 takes the guessing out of setting points, which can be hard programmed for any point. Current requirement of the MIC2778 is typically 1 mA, with two grades offered at different accuracies. MIC2778-2 has an accuracy of ±2% and the MIC2778-1 has an accuracy of ±1%.