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IC Knowledge Database

V4.1 · IC KNOWLEDGE DATABASE

IC Knowledge Database

Canonical bench knowledge connected to every motherboard using the same fitted IC. Board-specific facts stay linked to their source; missing values are not guessed.

182 IC profiles
Texas Instruments

BQ24780S

Charger / NVDC battery charge controller

2 boards

Notebook adapter detection, charge-path control and battery charging controller with SMBus control.

Signals / pins to know

SignalPurposeBench expectation
VCCIC supply / adapter input sense supplyConfirm the IC has a valid supply before checking downstream control signals.
ACDETAdapter-valid detection inputVerify the divider produces a valid adapter-detect level appropriate to the board design.
ACOKAdapter-present / valid status outputShould change to the valid state after VCC and ACDET are correct.
REGNInternal regulated gate-drive supplyCheck REGN before judging ACDRV/BATDRV gate drive.
ACDRVAdapter MOSFET gate driveVerify gate drive relative to CMSRC and the fitted MOSFET topology.
CMSRCCommon-source / adapter MOSFET source referenceUse as the reference when evaluating ACDRV operation.
BATDRVBattery-path MOSFET gate driveEvaluate only after supply, detection and control conditions are valid.
SMBusHost/EC charger configuration and telemetryCheck SCL/SDA activity, idle levels and absence of a stuck-low bus.

Common failure symptoms

  1. No charging or battery not detected while adapter power is present.
  2. Adapter connected but ACOK is missing after valid VCC/ACDET.
  3. Input MOSFETs do not open because expected ACDRV/CMSRC relationship is missing.
  4. REGN missing or unstable, preventing normal gate-drive operation.
  5. SMBus communication missing/stuck, preventing charger configuration.
  6. Intermittent charging caused by surrounding sense, MOSFET, connector or control-circuit faults; do not condemn the IC from one reading alone.

Typical test order

  1. Confirm adapter voltage, connector path, ground and input protection first.
  2. Check BQ24780S VCC.
  3. Check ACDET divider/input against the board schematic.
  4. Check ACOK state.
  5. Check REGN.
  6. Check CMSRC and ACDRV, then the adapter MOSFET gate/source voltages.
  7. Check BATDRV/battery-path control when the symptom involves battery connection or charging.
  8. Check SMBus SCL/SDA electrical state and communication activity.
  9. Only after prerequisites pass, compare remaining charger pins/measurements with the board schematic and manufacturer datasheet.

Datasheet / references

Texas Instruments BQ24780S datasheet / product documentation

  1. Board schematic and boardview for the exact motherboard revision.

Boards using BQ24780S

ZGRCCHARGER · ZGRC – Bench Power & Signal ChecklistNM-A931CHARGER · NM-A931 – Bench Power & Signal Checklist

Technician notes from solved repairs

No solved-repair notes have been collected for this IC yet.

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