TPS2553: About behavior of this TPS2553 when current over limit

user5077041

Part Number: TPS2553

Hi Team,

The TPS2553 was the constant current limited version and as we know the output voltage should drop first when current just over limit.

but why its protection when current limit event happen?

Test way:

Vin=5.2V ; Vout: 5V and sink current 500mA by Eload CC mode

over 7 years ago

0 Michael Tan over 7 years ago

TI__Expert 8420 points

Hi,
TPS2553 is adjustable current limit threshould . When the output curret up to the limit threshould(500mA) then current will be fixed, if loading load more than 500mA the vout will be drop then will be hiccup cycling (thermal protection) .

0 user5077041 over 7 years ago in reply to Michael Tan

Prodigy 40 points

if loading load more than 500mA the vout will be drop then will be hiccup cycling (thermal protection)

=> But actually the Vout no output immediately (5V=>0V) when loading load more then threshold (around 510 mA) , that makes me confused...

0 Michael Tan over 7 years ago in reply to user5077041

TI__Expert 8420 points

Hi ,

I think you device is enter to thermal recycling (output current hiccup), It is very easy go into thermal protect recycling since the delta V between the IN and OUT of the device is big . The total power loss : P=(Vin-Vout)*Ilimit_threshold .If device junction temperature exceed 135C will go into thremal pretect recycling, each cycly current be limit at 500mA. (this behavior within SPEC )

0 user5077041 over 7 years ago in reply to Michael Tan

Prodigy 40 points

Hi,

1. Yes, the IC outer temp. is very hot when loading load more then limit.

2. I also found that Vout is fixed around 5.1V when current does not exceed,

but when the current exceeds the limit, Vout changes directly to zero and does not drop slightly (ex: Vout = 5.0~4.9 V when I= 510mA )

So is this normal behavior?

0 Michael Tan over 7 years ago in reply to user5077041

TI__Expert 8420 points

Hi,

Yes, this is normal behavior .
You can try to use CR Mode set the load resistor to 9R or 9.5R to see the current limit behavior .

0 user5077041 over 7 years ago in reply to Michael Tan

Prodigy 40 points

Hi,
You clarified my question, thanks~

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TPS2553: About behavior of this TPS2553 when current over limit