• State TI Thinks Resolved
  • Locked Locked
  • Replies 3 replies
  • Answers 2 answers
  • Subscribers 62 subscribers
  • Views 198 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

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.

BQ24170: BQ24170

Guy Berwart
Prodigy 110 points
Part Number: BQ24170
Other Parts Discussed in Thread: TPS62913

Hello,

I designed a battery charger around the BQ24170 using the BQ2417X calculation tool V1 and filled all the parameters according to my needs (see attached).

The BQ24170 data sheet specifies:
ACOV provides protection to prevent system damage due to high input voltage. In bq2417x, once the voltage on OVPSET is above the 1.6 V ACOV threshold or below the 0.5 V ACUV threshold, charge is disabled and input MOSFETs turn off. The bq2417x provides flexibility to set the input qualification threshold. (Perfect!)

For my application, VIN is 9 VDC, R6 = 100K 1%, R7= 15K 1% and OVP is set for 12.2 Volts for safety (OVP max can't exceed 17.00 Volts which is VIN Max for the next regulator used: TPS62913)

Testing the circuit on my PCB, when VIN = exactly 9.00 VDC, OVPSET pin reaches 1.17 VDC, diode D3 starts to blink and the circuit goes in protection which is unusual regarding the 1.6V ACOV threshold announced above.

Did I something wrong?

So, do you have any explanation regarding this issue and how to solve it?

Thank you,

Kind Regards,

Guy Berwart

AIRTRONIC 2P16S - BQ24170.xls

  • 0
    TI__Mastermind 30025 points

    Dear Guy,

    Can you please explain more of the status of the charger? What is you battery voltage, what is your TS voltage, etc.? Can you provide waveforms of the input voltage/current, output voltage/current? OVPSET of 1.17 V would not indicate an under voltage fault.

    Section 9.3.9 indicates what scenarios can disable charging. Can you investigate if any of those conditions are being reached?

    Thanks,

    Mike Emanuel

    Please click "Resolved" if this answers your question.

  • 0 in reply to Michael Emanuel35
    Prodigy 110 points

    Dear Michael,

    Thanks for your reply.

    This is the measured parameters:

    VIN = 8.9 Volts (Ripple = 50mV)

    Vref= 3.3VDC

    VIset= 0.7VDC (strange! It should be above 120 mV to allow charging or less than 40 mV to stop charging...)

    OVOP= 1.15VDC

    VBAT= 7.72 VDC  not 8.4VDC and 1.2V Ripple @ 1KHz

    AVCC= 8.83 VDC

    VACSET= 0.8 VDC

    VRGEN = 6 VDC

    TS= 1..97VDC

    D3= ON means charging status but no current flows into the battery

    Now, I notice the following in the EVM guide:

    The bq2410 EVM board requires a regulated supply approximately 1 V minimum above the regulated voltage of the battery pack to a maximum input voltage of 16 Vdc

    As I rechecked the drawing and didn't find out any mistake, may be that VIN @ 9VDC is not high enough to get VBAT @ 8.4VDC and must change the input to 12 VDC and change some resistor value?

    Kind Regards,

    Guy Berwart

  • 0 in reply to Guy Berwart
    TI__Mastermind 30025 points

    Dear Guy,

    1) VISET is 700 mV, so it is above the threshold to charge.

    2) Yes you definitely need to make sure the input has enough headroom over the battery. Please make sure you increase the input voltage enough that you can support the 8.4 V battery. This is a buck battery charger so the input needs to have some room above the output for efficiency losses etc.

    Thanks,

    Mike Emanuel

    Please click "Resolved" if this answered your question.