• State TI Thinks Resolved
  • Locked Locked
  • Replies 1 reply
  • Answers 1 answer
  • Subscribers 63 subscribers
  • Views 337 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

BQ2000: Enable and disable battery charge

Suzzi maurizio
Prodigy 35 points
Part Number: BQ2000

Hello everyone,

I'm using the BQ2000 in a project. The IC should charge 2 NiMH battery while the device is connected to USB.

The device is controlled by a micro and the micro should be able to enable/disable the charge.

The device works fine and recharge batteries properly.

The issue I'm having is on disable and enable it.

I was supposing that I could use the TS pin in order to stop/retrieve the charge.

The TS pin is usually 40%Vcc through a resistor partition. The pull up resistor can be shorted using a PMOS put in parallel.

If I turn on the pmos the VTS will go higher the VLTF, when I turn it off VTS will go back at VHTF<VTS<VLTF.

As for the state diagram (page 4 of teh datasheet)  I expected to pass from Current regulation to Battery conditioning putting VTS = VCC. 

Then putting back the VTS = 0,4*VCC I expected (still being VBAT>VLBAT) that the IC will turn back on Current regulation state.

But that doesn't happend and to restart the charge I must disconnect and reconnect batteries or power supply.

Is cutting VCC the correct (and only) way to control the BQ2000?

 

  • 0
    TI__Guru**** 165886 points

    HI Suzzi,

    I recommend "tricking" the IC into thinking it is in sleep mode:

    Sleep Mode The bq2000 features a sleep mode for low power consumption. This mode is enabled when the voltage at the BAT pin is above the low-power-mode threshold, VSLP. During sleep mode, the bq2000 shuts down all unnecessary internal circuits, drives the LED output to high-impedance state, and drives the MOD pin low. Restoring BAT below the VMCV threshold initiates the IC and starts a fast-charge cycle. Normally, the bq2000 only enters sleep mode when there is no battery connected on the output and the charger is idling with nothing to charge. In addition, VIN needs to be high enough such that when VIN is present on the output, VBAT would be greater than VSLP.

    VSLP = VCC-1 so if you added a PFET shorting VCC to VBAT to VCC (body diode pointing from VBAT to VCC) and then a switch to the gate of that PFET to connect it connect, in theory, that should trigger sleep mode.

    Regards,

    Jeff