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BQ24610: Power dissipation calculation

Muhammad Fariz Bin Nor Azhar
Intellectual 480 points
Part Number: BQ24610

Hi Ti,

Currently i'm checking the charger IC thermal performance. Surprisingly the IC produce very high heat even the Iac current (base on datasheet) is just 25mA. For below condition, the measured Tc is 68degC @ 25degC ambient.

Is it normal for the IC to have high temperature like that?

How to calculate Power dissipation for BQ24610 IC?

Condition:

Vin=24V

Vout=12.381V

Iout=1.05A.

Thank you.

Best regards,

Fariz

  • 0
    TI__Mastermind 24075 points

    Hi Fariz,

       Power dissipation depends on a number of factors such as switching losses, conduction losses and layout. Section 10.2.1 Design Requirements of the datasheet dives into how choosing external components can result in power dissipation and how to calculate it (can focus on section 10.2.2.4). You can also refer to section 12 Layout Guidelines for advice when laying out your board, to maximize thermal dissipation. The temperature you observe is not expected, but reading through these sections can help increase the charger thermal performance.

  • 0 in reply to Kedar Manishankar
    Intellectual 480 points

    Hi Kedar,

    Thank you for the feedback. But in my case, the charger IC is the hottest component on my PCBA. Other surrounding components (ie: inductor, mosfet) have slightly lower temperature. It look like the IC itself is producing the high temperature. 

    How to calculate power dissipation of this IC?

    Thank you.

    BR,

    Fariz

  • 0 in reply to Muhammad Fariz Bin Nor Azhar
    TI__Mastermind 24075 points
    Hi Fariz,
    The IC itself only consumes current in the mA, and shouldn't heat up that much. Most likely the other power stage component placement (close to IC) is self-heating and also heating up the IC. How much copper pour is under the IC, how many layer board is this, and do you have sufficient thermal vias to dissipate the heat? I would direct you to the Layout Guidelines section of the datasheet, as it gives some key guidelines in board design. Can you also take a scope capture of PH, HIDRV, LODRV and inductor current? This can tell if the FETs are generating losses when being driven.
  • 0 in reply to Kedar Manishankar
    TI__Genius 10240 points
    Hi Fariz,

    We haven’t heard back from you. We are assuming you were able to resolve your issue. If not, just post a reply below or create a new thread if the thread has locked due to time-out.