Problems with tps61165

Saneoc Babaian

Other Parts Discussed in Thread: TPS61165

Hello ,

First of all I am sorry for my English , I still learn it .

I need to drive 27 white leds ( backlight for portable DVD player ) . For these reason I tried to use tps61165 .

I had maked the circuit from it's datasheet " Figure 18. Drive 27 LEDs for Media Form Factor Display " . The board is homemade , but I am sure that IC is soldered correctly and it's pin's are not conected one with another. CTRL pin is pull up through 4.7K resistor . I conected 27 leds how is shown in datasheet , and had conected power ( 5v ) - LED's reamained off . After that I had checked one more time all conections , but all is good . Oscillodram of SW pin show's that there are not pulses . IC didn't do anything . What must it do if CTRL pin is pull up , and where I must see to find the cause of these problem ?

I am sorry one more time for my English.

over 14 years ago

0 Jeff F over 14 years ago

TI__Guru*** 143830 points

Did you use a hand soldering iron to solder the IC onto your homemade board or did you use a hot air solder station or reflow oven? The 2x2 QFN package is very delicate and is almost always damaged if you touch one pin with a soldering iron without the entire IC first being heated on hot plate. The application note http://focus.ti.com/lit/an/slua271a/slua271a.pdf explains the problem. I suggest you order one of our EVMs http://focus.ti.com/lit/ug/slvu224b/slvu224b.pdf and connect your LEDs to it and test your circuit.

0 Saneoc Babaian over 14 years ago in reply to Jeff F

Prodigy 30 points

I had 4 pcs. of these chip . To solder one of it , I used a hand soldering iron , but second I soldered with hot air (2 pcs. remained) . that's not first time when i solder these package .

0 Saneoc Babaian over 14 years ago in reply to Jeff F

Prodigy 30 points

Kan yougive me a piece of advice , what to do to find where I comited mistake ?

I kan't buy the ev.module ,because it's inaccessible and too expensive for me . ( it's not very expensive , but I kan't buy it just for one time I need it ) .

Thank you.

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Problems with tps61165