TPS62090: This Part is Not Able to Generate 1.05V @ 1.3A from 5V Input Supply.

RAJ KUMAR

Part Number: TPS62090
Other Parts Discussed in Thread: TPS62091, TPS62093

Hello TI Team,

I am trying to get regulated output 1.05V @ 1.3A (Nominal current) from 5V Input Supply using the TI Component TPS62090RGTR.

Switching Freq.- 2.8MHz,

Start-up Time- 0.68ms

I tried to simulate the circuit on web-bench, TINA, and Pspice. But TPS62090 is not even able to generate a stable 1.05V @1.3A or higher current up to 3A. Please find attached waveform to see the simulated results.

All simulations like startup, Load Transient, Line(Input) Transient, and Steady State are completely failing.

You are requested to help me out with this. Shouldn't Use this component?

Thank You

Raj Kumar

over 1 year ago

0 Moheddin Pasha Shaik over 1 year ago

TI__Genius 13700 points

Hello Raj Kumar,

Thank you for reaching out. Please make sure that you use the right operating conditions.

I did not find any problem in WEBENCH for simulation, maybe you can try once again (Power Designer (ti.com)). Please find the WEBENCH simulation results of startup and steady state with you operating conditions. Similarly, you can perform for load transient.

WBDesign8_Startup-1.pdf

WBDesign8_Steady State-2.pdf

If you have further questions, please reach out again.

Thank you,

Regards,

Moheddin.

0 RAJ KUMAR over 1 year ago in reply to Moheddin Pasha Shaik

Prodigy 210 points

Hello Moheddin,

Thank you very much for the response!

I have gone through the simulation results that you shared and it looks good.

But my requirement is 2.8MHz switching frequency, could you please verify with 2.8MHz freq also.

Thank You

Raj Kumar

0 Moheddin Pasha Shaik over 1 year ago in reply to RAJ KUMAR

TI__Genius 13700 points

Hello Raj Kumar,

For your information:

How to use WEBENCH - How to use WEBENCH Power Designer | TI.com Video

WEBENCH power design for your operating conditions - Power Designer (ti.com)

You can change the switching frequency here,

Please find the WEBENCH simulation results of startup and steady state with you operating conditions.

WBDesign8_Startup-3.pdf WBDesign8_Steady State-4.pdf

If you don't have any further questions, please close the threat by clicking on Resolved.

Thank you,

Regards,

Moheddin.

0 RAJ KUMAR over 1 year ago in reply to Moheddin Pasha Shaik

Prodigy 210 points

Hello Moheddin,

Thank you for the response!

I know how to use web bench simulation tool. other than TPS62090, all simulations are coming satisfactory (like TPS62091, TPS62093).

Still, TPS62090 is showing misbehave. for example, its working for 1.3A output current But NOT for 3A.

Please preview attached web bench simulation results for the reference.

WBDesign26_Startup-1.pdf

I know this component may work with 1.3A. but my doubt is why it is not stable at higher load current.

Thank You

Raj Kumar

0 Moheddin Pasha Shaik over 1 year ago in reply to RAJ KUMAR

TI__Genius 13700 points

Hello Raj Kumar,

Please refer the datasheet page (9) to understand more clearly about the startup current limit for TPS62090. (TPS6209x 3-A High Efficiency Synchronous Step Down Converter with DCS-Control datasheet (Rev. C) (ti.com))

Your design conditions are hitting a startup current limit check that is done in WEBENCH(R) Power Designer.

While the TPS62090's nominal current limit is 4.6A, the TPS62090 limits the switch current limit to ~1.5A during startup while the charging output Vout is still below 0.6V.

With Vout=1.05 V and Iout=3A, the equivalent steady-state resistor load at the output is 350mohm. WEBENCH(R) Power Designer currently requires that designs be able to startup into the equivalent stead-state resistor load. More on that later. In your case, applying 350mohm at the output during startup would, ignoring current ripple, push the switch current above 1.5A (0.6V / 350mohm = 1.71A > 1.5A limit). To get a passing design, Iout needs to be below 2.5A according to your desired Vout.

We know this requirement is stringent and is failing valid 'steady-state' designs and we know that in real systems full load is typically applied once the output is regulated and out of startup.

Thank you,

Rergards,

Moheddin.

0 RAJ KUMAR over 1 year ago in reply to Moheddin Pasha Shaik

Prodigy 210 points

Hello Moheddin,

Thank You so much for clearing my doubts. it's been really helpful discussion.

Thanks You

Raj Kumar

Power management

Power management forum

TPS62090: This Part is Not Able to Generate 1.05V @ 1.3A from 5V Input Supply.