TPS62420: DC to DC Converter Heating Up

Jebin Satheesh Kumar

Part Number: TPS62420

Hi Ti Team.

TPS62420 are heating up and i have checked Pin No 10 to Gnd i a am getting 24Ohm. Can any one help me to find out what went wrong.

Jebin

over 6 years ago

0 Jebin Satheesh Kumar over 6 years ago

Intellectual 290 points

Hi Ti Team,

Operating Conditions :

Input : 3.4V - 4.3V

Load Current @ 1V8

Continues Load : 350mA

Peak Load : 450mA

Ideal Condition : 20 ~ 50mA

Load Current @ 3V3

Continues Load : 600 ~ 650mA

Peak Load : 800 ~ 900mA

Ideal Condition : 10 ~ 30mA

0 Jebin Satheesh Kumar over 6 years ago in reply to Jebin Satheesh Kumar

Intellectual 290 points

0 Alfonso Furio over 6 years ago

TI__Expert 3645 points

Hello,
Can you describe your problem and application? To identify the root cause of your issue, I can start checking your schematic.

0 Alfonso Furio over 6 years ago in reply to Alfonso Furio

TI__Expert 3645 points

Hello,
From your schematic, I noticed that you used C98 as feedforward capacitor even if not recommended for the first output. The use of Fb is also not recommended in our documentation and please ensure (especially for the input) that they are not operating in resonance or you can damage the device. Can you provide the scope plots of Vout1, Vout2, SW1, SW2, Il1, IL2?

0 Dorian Brillet de Cande over 6 years ago in reply to Alfonso Furio

TI__Genius 14876 points

Hi Jebin,

We haven't heard back from you. Did you collect plots of Vout1,Vout2, SW1, SW2, Iload1 and Iload2?

When you are saying that the TPS62420 are heating up, did you encountered failures? Could you provide number regarding the temperature the system is facing or has faced?

Thank you very much!
Best Regards,

Dorian

0 Jebin Satheesh Kumar over 6 years ago in reply to Alfonso Furio

Intellectual 290 points

Hi Alfonso,
What you mean by "The use of Fb is also not recommended in our documentation and please ensure (especially for the input) that they are not operating in resonance or you can damage the device" Since the datasheet recommend to connect the FB1 Pin to VOUT1.

Jebin

0 Alfonso Furio over 6 years ago in reply to Jebin Satheesh Kumar

TI__Expert 3645 points

Hello,
sorry for my delayed reply, I was out of the office for vacation. I can simply suggest checking well how to dimension the Fb, especially at the input. An Improper use of them can create issues such as unwanted resonances due to the combined use of Fb and a capacitor (Low Pass filtering). You can have a peak (at resonance) in the frequency response of this LP filter that can amplify noise or ripple instead of attenuate. To mitigate this resonance peak, you should use damping, adding typically a resistor in series to the ceramic cap of this LP filter. What I described is the worst case, dimensioning correctly you shouldn't have any problem.

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TPS62420: DC to DC Converter Heating Up