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  • TI Thinks Resolved

High Input Voltage 60v+ battery charge controller

Hi,

I've searched extensively on TI website looking for something like a Buck switcher designed as a battery charge controller, with features such as external FET to reach 5-10A charge current, CC/CV two stage charge profiles, EOC timers, pre-charge current limiting etc for Li-ion chemistry. However key to my requirement is 60V input supply voltage and a charge voltage that can reach the same. 

I have not found any suitable IC. Did I miss something? Perhaps TI has some recommendations of how to use lower voltage ICs to operate from these high voltage levels.

Thanks in advance.

Aidan

  • Guru 66945 points
    Aidan,

    I can recommend a two chip solution where you use a 60V buck converter to step down the voltage for one of the battery chargers. Is that acceptable?

     

  • In reply to Jeff F:

    Hi Jeff,

    That's not ideal actually as I will just need to step back up again using a buck/boost charger. Inefficient and more complex and costly. The battery is also 60V (16S Li-ion)

    Aidan

  • Guru 66945 points

    In reply to Aidan Walton:

    Aidan,

    Unfortunately, we do not have a single chip solution. There a few a reference designs that could possibly be modified to meet your specification.

    www.ti.com/.../index.html charger

     

  • In reply to Jeff F:

    Hi Jeff,

    Actually this is kinda where I'm looking for a pointer. Currently I am strongly considering an alternative supplier (Linear) they recently introduced a mult-chemistry rather simple (low component count) effective charge controller that operates directly from up to 60V. Unfortunately they do not have a transient spice model for it and it also does not support programmable current. So only ON/OFF control.

    I would be happy to consider a modified TI design as I am doing all my existing modelling inside TINA-TI. This would be especially true if you have transient models available for the device.

    I'm still working on the ORing supply that switches battery or mains, this is almost complete, after which I will integrate the charging functions. So if you could perhaps suggest something that you might be reasonably confident would work, I will work on it next.

    Key functions:

    Li-ion support for over 15S cells. i.e operating voltage 42-63 V

    Low charge current limiting (Pre-charge function)

    Programmable (MCU controlled) charge current ( to allow different charge profiles from a mains power source that is not specified to deliver full system load and full charge current simultaneously. )

    Timed EOC cut-off.

    Reverse current protection. In case battery voltage is above charge voltage. And related, a charge algorithm that can deal with a potentially regular droop in the supply voltage ( this could be heavily loaded by the system and in extreme conditions the supply voltage to the charger may fall below the battery voltage for a few mS, especially if the battery is fully charged.

    If you have a little time your experience would be very much appreciated. Otherwise I shall probably opt for the other manufacturer.

    All the best
    Aidan

  • In reply to Aidan Walton:

    Aidan,

    Thanks for the requirement information. We understand the requirements are basic charger features such as constant current, constant voltage, dynamic power management, termination etc. We have good portfolio covering low voltage but no 60V chargers. The reference designs recommended by Jeff might be the best option from our perspective.

    Regards,

    Eric

    Texas Instruments

    Battery Charger Solutions

  • In reply to ezhao:

    Thanks Eric and Jeff,
    You have given me food for thought. So trawling through the ref designs I came across the TIDA-00355 LLC resonant controller based solution. Ironically I am already using an LLC converter for my primary 60V DC supply. However your design uses two separate feedback path for CC and CV. My existing LLC design has only voltage control in the direct regulation loop (Over current off the transformer). However I had not considered it as a CC/CV source, but this might actually work and if so I could eliminate a separate switcher altogether. That could be quite neat cost effective and more efficient. I will have to limit the charge function to times when the system is in standby, but that's probably not unreasonable. Perhaps I can look to modify this somehow in a similar way. However from some experience I know these to be temperamental and tricky to get stable. So wish me luck :)

    However I can not find any simple buck designs that will handle the higher voltages.
    Once again thanks for the support. Back to the bench!
    Aidan
  • In reply to Aidan Walton:

    Aidan,

    Wish you can successfully implement the CC/CV on your current LLC converter.

    Regards,

    Eric

    Texas Instruments

    Battery Charger Solutions

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