CCS/LM34936: PD charge fail on 5370 of Dell and Y9000K of Lenovo

Jianping

Part Number: LM34936
Other Parts Discussed in Thread: TPS65987D, LM5176

Tool/software: Code Composer Studio

Hi,TI's expert:

we're run into a trouble for the output capacitor choose and confirm the RC network of comp pin of LM34936

becuase it's PD charge fail on Dell_5370(inrush issue,see the capture1) when using low ESR(30mR) capacitor or re-work the RC network(R683 to 3.3K ,C482 to 300pF of comp pin ,

special the temperature rise to 57°C,the issue more terrible.

if change the E- capacitor(EC13 on our shcematic) to above ESR.150mR, the 5370 of NB charge normal.but the Y9000K(Y900K,20V/5A) fail(detail see the below captures)

i tried tune the RT/SYNC pin and COMP pin on LM34936,but get the result didn't compatibility them（Dell_5370 and Lenovo_Y9000K).

as below circuit show to you reference.

kindly advise you give me some comment or solution for the issue.

thanks!

5370 of Dell charge OK when using the E-cap of Higher ESR(above 150mR)

Y9000K charge fail when change E-cap of High ESR(above 150mR) on output power path.

the Y9000K of NB charge OK when re-work the RC network of Comp pin of LM34936 and E-cap of Higher ESR(above 150mR)

or change the E-cap of Lower ESR(30mR),it's same as effect(charge OK)

the 5370 of NB charge fail when re-work the RC network of Comp pin of LM34936 and E-cap of Higher ESR(above 150mR)

or change the E-cap of Lower ESR(30mR),it's same as effect(charge fail)

over 5 years ago

0 Jianping over 5 years ago

Intellectual 550 points

Hi,TI's Expert:

our PD solution has TPS65987D, the interal power switch was withsatand 10A inrush max.

the spec,you can download it from as below link.

thanks!

0 Jianping over 5 years ago in reply to Jianping

Intellectual 550 points

Hi,TI's expert:

sorry for lost the schematic upload.

0 Garrett Roecker over 5 years ago in reply to Jianping

TI__Mastermind 21720 points

Hi Jianping,

Sorry to hear you are having issue with your schematic.

I have a few questions that should help me understand what is happening.

1. What is the input voltage during this operation?

2. Please confirm the switching frequency of the LM34936. It looks like there might be a few options.

3. What is the maximum load current for each of the 4 output voltages in the application

Thanks,

Garrett

0 Jianping over 5 years ago in reply to Garrett Roecker

Intellectual 550 points

Hi,Garrett:

thanks you reply!

1. the input voltage has 19v DC from adaptor.

2. the frequency be follow EVM of LM34936, it's 300K.(but i chang it to 380K if fix the issue)

3. the 5V,9V,12V 15V maximum current 3A; the 20V loading max 5A;

0 Jianping over 5 years ago in reply to Jianping

Intellectual 550 points

Hi,Garrett:

do you have any updated for the issue?

0 Garrett Roecker over 5 years ago in reply to Jianping

TI__Mastermind 21720 points

Hi Jianping,

I have been working with your local TI field engineer on this issue. As to not duplicate the effort I am going to close this thread.

From the LM34936 stand point it looked like the loop compensation needed tuned for the application.

Thanks,

Garrett

0 Jianping over 5 years ago in reply to Garrett Roecker

Intellectual 550 points

Hi,Grrett:

may you share the AE information to me for contact them?

regarding loop compensation tune methodology,

could you share some document of LM34936 to us for study ?

thanks!

0 Garrett Roecker over 5 years ago in reply to Jianping

TI__Mastermind 21720 points

Hi Jianping,

I am working with Antony Lin.

To estimate the loop of the LM34936, I suggest using the LM5176 quick-start calculator

The LM5176 and LM34936 have have the same control loop architecture so the quick-start calculator can be used interchangeably.

Thanks,

Garrett

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CCS/LM34936: PD charge fail on 5370 of Dell and Y9000K of Lenovo