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BQ2004: BQ2004 - NiMH charger for the function of over discharging protection

Jason Dai
Expert 3720 points
Part Number: BQ2004
Other Parts Discussed in Thread: BQ24190

Dear E2E,

customer is looking for NiMH battery charger solution with the function of over-discharge protection.

I didn't see power path FET in reference circuit. could this part have the protected function of over-discharge?

How to make the circuit to do it?

if no, any other suitable part could support this case?

BR,

Jason

  • 0
    TI__Guru 56650 points
    First, let us clarify the customer requirement: over-discharge protection
    To prevent the system crash, we have to deliver the battery power to system immediately. So, if a charger solution or IC uses external BATFET, the battery FET's body diode can pass the battery power to the system load, even the FET is off.

    But, the over-discharge protection requests the battery FET's body diode block the battery power to the system load.

    So, the solution needs a back to back BATFETs if the BATFETs are external. And the two BATFET's gate circuits are in depended: one is for charge control; another one is for discharge control. So far for external BATFET solution, we only have charge control BATDRV parts. Customer has to develop the discharge control circuit by themselves according to the detail system requirement. BTW, bq2004 even doesn't have BATDRV control circuit.

    For integrated BATFET solution, the BATFET can block both charge and discharge current. It can support over-discharge protection. But, we don't dedicate NiMH charger with integrated BATFET. The host controller has to provide charge profile control for the NiMH battery. And then, you can check bq24190 family part.