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TIDA-01093: Mosfet FDB2614 is with high Rdson & Drain current up to 35 A only

smash Micheal
Intellectual 1000 points
Part Number: TIDA-01093
Other Parts Discussed in Thread: BQ76940, BQ76930, BQ76930EVM

Dear All,

TIDA-01093 schematic, is having low drain current Mosfet & high Rdson, can i replace it with other mosfets, with high Drain current Mosfet & Low Rdson eaisly without modifying its driver circuit ?

Also, what if i, plan to mount 10 mosfets for charging path & 10 mosfets for discharging Path in current design, instead of 3 mosfets for each path ? Will i need to change driver circuitry ? 

Also am thinking to mount Mosfet whose specs are as follows:-

1.) Drain current 100A.

2.) Rdson  3m ohm.

3.) Vgs th 4v min. 

My continous current through mosfet discharge path will be 100A, as am using 10 mosfets in parallel ,will use just 10A from each mosfet , which will help regulate temperature of mosfets as well.

Rohit

  • 0
    TI__Guru 54715 points

    Hi Rohit,

    In general when looking for MOSFETs  as the Vds rating goes up the Rdson also goes up and the current capability goes down. Different MOSFETs can be used in the circuit.  The BQ76940 has resistive drivers, turn on (pull up) resistance is about 5k, turn off is shown in the data sheet.  The TIDA-01093 driver circuit however uses the BQ76940 FET drive outputs for signals, current comes from BAT+ for turn on and turn off is accomplished with the expedite shutdown circuit described in the design guide section 2.1.  The driver will likely work with more FETs but may need some value adjustments.  Since the driver needs some headroom for the expedite circuit trigger, be sure to keep a good REGSRC voltage so the DSG and CHG outputs operate in regulation. 

  • 0 in reply to WM5295
    Intellectual 1000 points

    Hi ,

    Thanks for solution.

    I wanted to use, MCU gpio for driving Mosfet instead of Bq76930 upper & bottom CHG & DSG pins respectively.

    Can i simply, replace it with 2 different MCU gpio's, and can i free {(CHG_U & CHG_B)  & (DSG_U & DSG_U)} pins of Bq76930 ? [ This will help me to have full access with MCU instead of AFE].

    Secondly for Part which am trying to use for Mosfet is "IPB042N10N3G" & pacjkage is D2 PAk, please confirm if i can simply replace or not, or if any trimming is required for continous 100A than please share.(Charge path 10 mosfets & discharge path also 10 mosfets, all will be in parallel)

    Rohit

  • 0 in reply to smash Micheal
    TI__Guru 54715 points

    Hi Rohit,

    You can control FETs with a MCU, you will typically need an interface circuit to go from the low level voltage of the MCU GPIO to the higher level of the FET gate and particularly the large swing of the charge FET.  You might see http://www.ti.com/power-management/gate-drivers/overview.html .  An isolated driver is an option to the weak drive and transistor circuit on the BQ76930EVM charge driver.  One complication with MCU control is the speed of response of the discharge FET to a sudden overload, a short circuit response is often very fast such as from the bottom BQ76930 while a MCU response may be slower.  Use appropriate logic as needed. 

    The MOSFET you note is probably very capable, check with the supplier or manufacturer for specific considerations with that component.  For MOSFET options from TI please see http://www.ti.com/mosfet