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[FAQ] TLV9022: How To Protect 48-V Batteries from Overcurrent and Undervoltage

Part Number: TLV9022
Other Parts Discussed in Thread: TL431

I would like to protect a 48V Lithium-Ion battery from undervoltage and overcurrent. These types of batteries cannot have a voltage value below their rated value and discharge current above their rated value. Is there a solution for a dual-comparator design that accomplishes both undervoltage and overcurrent protection?

  • It is understood that some types of high-voltage batteries behave this way. Using the TLV9022 dual, high-speed comparator with input fault detection is a great comparator for this type of application. The fault protection of this specific device allows inputs up to 5.7V with a valid supply value of 3.3V. This means that the input voltage reference can be set to a higher voltage level, improving accuracy.

    One requirement for any high-voltage application with low-voltage devices is a fixed voltage reference for the supply of the comparator. This can be accomplished using the TL431 shunt reference. Once a fixed voltage reference is established, the first channel of the TLV9022 is used for undervoltage protection and the second channel of the TLV9022 for overcurrent protection. Both comparator outputs are combined by shorting both open-drain outputs together in what is referred to as AND configuration.

    Please see an implemented solution and further explanation in this app note: