TPS2491: About Response to a Hard Output Short (Figure 14)

Tsukui Yusuke

Guru 21930 points

Part Number: TPS2491

Hi,

Could you tell me about TPS2491 datasheet page15 Fig14?
Please tell me the reason why the gate voltage rise dramatically.
I am pointing to the part indicated by the red frame.
Could you give me your advice?

Best Regards,
Yusuke/Japan Disty

over 8 years ago

0 Tsukui Yusuke over 8 years ago

Guru 21930 points

Hi,

Can I get the information?
Customers need that information for design.
If you need more information or if I should clarify my comment ,
please let me know.

Sorry for rush you.

Best Regards,
Yusuke/Japan Disty

0 Eric Wright over 8 years ago in reply to Tsukui Yusuke

TI__Mastermind 42795 points

Please tell me the reason why the gate voltage rise dramatically.

Do you mean FALL? The GATE voltage is falling, not rising. Falling GATE voltage as a result of an OCP event is how the circuit is designed to operate.

0 Tsukui Yusuke over 8 years ago in reply to Eric Wright

Guru 21930 points

Eric-san,

Thank you for you response.
I want to talk about the waveform before OCP occurs.
In this waveform, Gate starts from 60V and Timer starts from 5V.
Could you tell me the reason for this?

Best Regards,
Yusuke/Japan Disty

0 Eric Wright over 8 years ago in reply to Tsukui Yusuke

TI__Mastermind 42795 points

TIMER starts from 0-V. I think the confusion is caused by poor graphics in the figure (TIMER is GREEN but OUT is light BLUE which appear almost the same).

GATE will start about 14V higher than OUT and TIMER will start at 0-V.

0 Tsukui Yusuke over 8 years ago in reply to Eric Wright

Guru 21930 points

Eric-san,

Thank you for your response and support.
Just as you said.I mistook writing timer and out.
Sorry for the confusion.

However,The out and gate voltages are high.
(Gate≒60 ,OUT≒48V)
What is this status?

Best Regards,
Yusuke/Japan Disty

0 Eric Wright over 8 years ago in reply to Tsukui Yusuke

TI__Mastermind 42795 points

Just before the OCP event occurs (far left side of the graph), the TPS2491 was ON. Therefore, OUT = IN = 48V and GATE = OUT + ~14V = ~62V

0 Aramis P. Alvarez over 8 years ago in reply to Tsukui Yusuke

TI__Genius 10370 points

Hi Yusuke-san,

On top of what Eric said, if the customer/yourself would like a more detailed explanation on all of the equations and methodology behind our hotswap controllers, please go to our app note at www.ti.com/hotswap ==> Click on “Technical Documents” ==> Click on “Robust Hot Swap”. It goes step by step to explain what the waveforms should look like for Vin, Vout, Iout, Vgate, Vtimer. I hope this helps :-)

Best Regards,
Aramis P. Alvarez

Power management

Power management forum

TPS2491: About Response to a Hard Output Short (Figure 14)