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CSD19535KCS: CSD19535 Heating problem

pil joo huh
Intellectual 370 points
Part Number: CSD19535KCS
Other Parts Discussed in Thread: CSD19535, TL431, TLV431,

Dear all

I will design for constant current circuit.

Please check to the circuit and advise to me

1. Condition

    -. Input Voltage : DC 60V

    -. Id = 250~300mA

2. Problem

  1) CSD19535 FET heating (about 80~90 ℃ at 25 ℃)

      -. Could you improve method(included Heat sink) ?

      -.  Could you recommend to Voltage reference(TL431 or TLV431)?

   2)  If TL431 output voltage is higher, CSD19535 Heating temp. is lower

       -. For example TL 431 Vref voltage is increase.

Thanks and Br

PJconstant_current_TI.pdf

  • 0
    TI__Prodigy 160 points

    Hi,

    We are presently looking into the problem. Just to make sure we completely understand, for Id=250mA, the voltage across MOSFET is 60-0.25*(33/2)=55.875V. Therefore, the steady state power loss is 55.875*0.25=14W (approx). From Fig. 10 (datasheet of CSD19535KCS), it is apparent that the device is still under Safe Operating Area so the peak temperature is under 150C. 

    If the primary goal is to reduce the operating temperature of the mosfet, you can adopt few of the following methods:

    1) Reduce input voltage 

    2) Use heat sink with airflow

    3) if possible use another resistor in series to divide the voltage further, such that lower voltage builds across mosfet

    I hope this shed some light to the solution.

    Please let us know if you have any further question.

    Best Regards,

    Ankan De