SLUAAG7 October   2021 BQ25720

 

  1.   Trademarks
  2. 1Introduction
    1. 1.1 Type-C Power Delivery (PD) Connection
    2. 1.2 Type-C Battery Charging Topologies
    3. 1.3 BQ25720 Overview
  3. 2Design Considerations for Notebook Applications
    1. 2.1 Vmin Active Protection (VAP)
    2. 2.2 Fast Role Swap (FRS)
    3. 2.3 Processor Hot Indication
    4. 2.4 Two-Level Battery Discharge Current Limit
    5. 2.5 Pass Through Mode (PTM) Operation
    6. 2.6 Seamless Mode Transition
    7. 2.7 Current and Power Monitor
    8. 2.8 Input Source Dynamic Power Management
    9. 2.9 Power Up USB Port From Battery (USB OTG)
  4. 3Test Results
  5. 4Summary
  6. 5References

2.4 Two-Level Battery Discharge Current Limit

To prevent triggering overcurrent protection and avoiding battery wear-out, BQ25720 includes a two-level battery current limit (IDCHG_TH1 and IDCHG_TH2) for more precise battery discharge current protection.

When the battery discharge current exceeds IDCHG_TH1 for at least IDCHG_DEG1 deglitch time, PROCHOT is asserted immediately. If the discharge current reduces to lower than IDCHG_TH1, the time counter resets automatically.

When the battery discharge current exceeds IDCHG_TH2 for at least IDCHG_DEG2 deglitch time, PROCHOT is asserted immediately. If the discharge current reduces to lower than IDCHG_TH2, the time counter resets automatically.

Additionally, if discharge current is higher than 133% or 200% programmable IDCHG_TH2 after 250 µs deglitch time, battery overcurrent protection (BATOC) fault is triggered. BATOC is not a latch fault, so after BATOC fault is removed, with 250 ms relax time, the converter resumes switching automatically.

Figure 2-4 Two-Level Battery Discharging Current and BATOC Fault