BPS of supplemental battery

Owned by Chenao Yuan
Last updated: Nov 27, 2020 by tanish shah
2 min read

Following information is a summary of a TI design note. Available: http://www.ti.com/lit/ug/tidu020a/tidu020a.pdf

Comparator with Hysteresis

This is a circuit that adapt from the TI design note, the hysteresis voltage will be determined by Rh.

Suppose VH is the upper threshold and VL is the lower threshold. The value of Rh can be determined by those two equations.

For example, in the case of a 12v lead-acid battery, if the upper threshold is 11v, lower threshold is 10v, the Rh, Ry will be 1k and 10k when Rx is 100k.

In this circuit, the Vout will be HIGH when the voltage < 10v and LOW when voltage >11v. For battery undervoltage protection, the output should be opposite for a safer operation.

We are using nickel metal hydride batteries in series, the low threshold is 10v. This comparator is the design that was chosen to be used. Schematic and simulation to be uploaded to the doc as well.

Updates for June 13th meeting