• State
  • Locked Locked
  • Replies 2 replies
  • Subscribers 63 subscribers
  • Views 750 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

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.

Original question:

12v in 50v out boost converter for pulsed discharge application

50V-200V Boost converter for pulsed discharge application (Adj Out Voltage)

d_zero
Genius 4765 points
Other Parts Discussed in Thread: LM5156H, LM5155, LM5156-Q1

Dear *,

please can you suggest a device for 50V-200V Boost converter for pulsed discharge application (Adj Out Voltage)

Vin 24V

Vout from 50V to 200V

Iout from 0.3A( for 50V) to 0.075A ( for 200V) [ Pout 15W]

Adjustable output voltage via feedback pin

the output capacitor is 100uF and pulsed load ton max = 100us , toff= T-ton = (1/200Hz) - 100us = 4.9ms

100us discharge time, 4.9ms charge time.

2) if the same inductor and Rs is used for voltages from 50V to 200V, does that mean the the current through inductor for smaller voltages than 200V will be higher before it hits the current limit?

is it somehow possible to adjust the cycle by cycle current limit for smaller output voltages from the outside of the BOOST IC?

Best Regards,

David.

  • 0
    TI__Mastermind 21720 points

    Hi David,

    Thanks for reaching out with your question and for considering TI as part of your design solution.

    First, is isolation required for this design? I ask as the maximum output voltage is around 200V. This will dictate the best solution for your application. If isolation is not required this reference design would be a good starting place.

    www.ti.com/.../PMP21781

    As the output voltage is dynamically changed the the inductor and the current sense resistor will be the same value. My suggestion is to start the design with the worst case operating condition. For this design it will be when the output voltage is 200V and the output power is 15W. 

    Please let me know if you have any questions.

    Thanks

    Garrett 

  • 0 in reply to Garrett Roecker
    Genius 4765 points

    Hi Garrett,

    we changed the Vout to be from 75V to 200V so that the LM515x is always in DCM mode. Is the LM5156H a good choice over LM5155 or LM5156-q1 

    1)

    I used the calculator ( attached ) for 75Vout and 200Vout, Please can you check the calculations and stability graphs?

    2) 

    In the calculations i always get Rsl to be 0 ohm is that ok?

    -----------------------------------------------------------

    Rt= 82kOmh -> 266.4KHz

    Inductor 47uH ->Wurth 7687714470 

    Mosfet BSC500N20NS3GATMA1 

    Diode CD214A-FS1G 

    Where to get or how to calculate the diode Qrr ?

    Rs = 50mOhm

    Cout = 3x33uF 250V EKXJ251ELL330MJ20S 

    Css = 2.2uF , Rcomp= 1Mohm, Ccomp = 1nF, Chf = 1pf

    75V_LM5155_56_Excel_Quickstart_Calculator_for_Boost_Converter_Design_20200828.xlsx

    200V_LM5155_56_Excel_Quickstart_Calculator_for_Boost_Converter_Design_20200828.xlsx

    Best Regards,

    David.