SNOAA65 December   2020 TLV9022

 

  1.   Introduction
  2.   Design Process
    1.     Voltage Regulation
    2.     Undervoltage Protection With Hysteresis
    3.     Overcurrent Protection
    4.     Final Considerations
    5.     Simulation Results
  3.   Design References
  4.   Design Featured Comparator
  5.   Design Alternate Comparator

Design Process

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For this design, a 48-V, 20-Ah lithium-ion battery was selected. Monitoring a 48-V lithium ion battery can be achieved using the TLV9022 device in combination with the TL431 shunt reference. The TLV9022 is a dual-channel, open-drain comparator that will be used to implement overcurrent and undervoltage protection. This comparator was selected for its low-input offset voltage and fast response time. Additionally, this comparator has fault-tolerant inputs that can go up to 6V without damage. The design process will be broken down into three main sections: Voltage Regulation, Overcurrent Protection, and Undervoltage Protection with Hysteresis. This design has design parameters and desired outputs shown in the following table.

Design Parameters and Desired Outputs (1) (2)
System SupplyUndervoltage LimitUndervoltage ResetOvercurrent LimitComparator Output Status
TypicalVUVVRESIOCOvercurrentUndervoltageNormal Operation
29 V10 V12 V10 ACH1-HIGHCH1-LOWCH1-HIGH
CH2-LOWCH2-HIGHCH2-HIGH
  1. The design parameters and desired outputs table assumes a typical value of 29-V for the 48-V battery as it is the midpoint between the maximum voltage value and the undervoltage limit.
  2. The design parameters and desired outputs table assumes only one condition (OC or UV) is met at a time at a time.