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LM3429 DC-DC Boost Problem after Replace New IC LM3429(Simple buy) Please Help

Other Parts Discussed in Thread: LM3429

i am new... any i have a little English language.

i am want to know How to solve problem..

i have a new PCB Evaluation Board LM3429 Boost DC-DC Converter

My ploblem i am remove Ic in Evaluation Board and Replace IC Sample Buy From Digi-Key Thailand After Replace IC Circuit don't constant current when i am Turn Up Volume 10-12 Vol Some time Duty Cycle can't Invariant itself. and Frequency Switch pin Gate Frequency decreases or Frequency increases. and other problem Resister R8 have Burn

i am have to check Voutput Before Replace IC

fig Before Frequency = 2.294Hz
Red = Vin ,Green = Test Point 11 , Blue = Output Voltage 

 

and Test Point 11 Sw gate Frequency = 552Khz
Red = Vin ,Green = Test Point 11 , Blue = Output Voltage  

After Replace IC new (Sample Buy)  Frequency Change = 1.093KHz
Red = Vin ,Green = Test Point 11 , Blue = Output Voltage  

and Test Point 11 Sw gate Frequency = 532Khz
Red = Vin ,Green = Test Point 11 , Blue = Output Voltage 

Thank you very Much

Siripongl
Email:siripong@gets.co.th or s.lapnitayaphan@gmail.com

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Date 27-2-2013

I have copied the pcb AN-1986 LM3429 Boost Evaluation Board and assembly device and test connect series, 14 led tube 2 sets in parallel.


My problem Circuit not Constant Current(1A) When I am increase Voltage(10-15V) Current increases too. How to solve Problem Thank

When Voltage input is 9.786V Current 1.013A

And Voltage input 13.162V Current is 1.394A

And Voltage input 15.626V Current is 1.581A