• State Resolved
  • Locked Locked
  • Replies 5 replies
  • Subscribers 63 subscribers
  • Views 362 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.

BQ24650: 5V operation and VCC current

Zakharova Antonina
Prodigy 90 points
Part Number: BQ24650

I power BQ24650 from 5V source

1. As REGN is powered from LDO its voltage can not be higher than VCC. Actually it is around 5V. Then I get say 4.8V on BTST and (considering output around 4Volts) high-side mosfet Vgs<1V. So it is closed and charger is turning on. Is it as expected to be? What is the lowest expected Vin - Vsrp for charger to operate? Is there some way to make it work with 5V input and one Li-ion output?

2. When I operate on Vin=7V I get 1V drop on 10Ohm resistor connected to VCC pin. That means VCC current 100mA which is more than expected from datasheet. Is it indicates some IC failure or normal?

  • 0
    Prodigy 90 points
    correction 1. .... and charger is NOT turning on....
  • 0
    TI__Mastermind 20570 points
    Regarding 1, please refer to datasheet page 14 section 8.3.7 to make sure all the charge enable conditions are met and none of the charge disable condition is there. The typical value of sleep mode thrshold, VIN-VSRP, is 100mV.
    Regarding 2, is the part switching? Any load connecting at the output?
  • 0 in reply to Jing Zou
    Prodigy 90 points

    Regarding 1,
    VMPPSET = 1.3V,
    VCC=5V,
    SRN=3.8V,
    VCC is taken from DC battery and there is no incoming AC source, except BQ24650 swithcing noise. I don't have scope to see it. And also I have 10V TVS diode parallel to input just in case.
    30 ms - waited
    REGN= 4.8V
    Vref=3.3V
    Vfb=1.7V
    TSHUT can not detect but IC is cold
    TS=1.8V
    STAT1 LED every 1s is blinking shortly (100ms)
    output is connected to 1S li-ion

    Regarding 2 - maybe IC was damaged. I changed and now there is no significant current into VCC. Now this circuit work similar to 1 (which is not charging essentially)
    VMPPSET = 2V
    SRN=3.8V
    REGN=6V
    vref = 3.3V
    Vfb=1.7V
    TS=1.8V
    STAT1 LED every 1s is blinking shortly (100ms)
    output is connected to 1S li-ion
    HIDRV=5.8V
    LODRV=0V

    AGND and PGND are connected in one point as a 4-rays star from thermal pad to (1)-bulk PGND plane on back side of PCB, (2)-GND IC pin, (3) and (4) AGND traces on top side of PCB.
    SRP and SRN are in Kelvin connection from Rsns with 0.1u (also tried 2.2u) capacitance between

  • 0 in reply to Zakharova Antonina
    TI__Mastermind 20570 points
    Can you please show scope capture on VCC and SRP along with STAT pin in both conditions?
    Please also show your schematic.
  • 0 in reply to Zakharova Antonina
    Prodigy 90 points

    In fact it was mosfet soldering problem. It took quite a long to debug but no problems with design. Thank you for advice anyway.