DLPA2005: Setting LED Current to 2Amp

QI MAO

Part Number: DLPA2005
Other Parts Discussed in Thread: DLPC3470, DLP3010EVM-LC, DLP2010LC

Dear TI,

Resently, I am tsesting my DLPA2005 + DLPC3470(firmware version: dlp2010evm-lc_7.3.1) + DLP2010A FQJ+ LE B Q8WP application(Based on DLP2010EVM-LC)

Tyring to set the LED current to 2A by sending these commands.

Write RGB LED Current PWM (54h)

Write RGB LED Max Current PWM (5Ch)

The Maximun current I can get is about 1000mA(0x0194), higher LED currnent settings will rising the anode voltage of LED to about 6V, with 1000mA LED current.

It seems that DLPA2005 is in VLED Overvoltage (VLED_OVP) Fault conditon.

I noticed that the DLP3010EVM-LC is capable for 2.4A LED current by changing the Inductor of LED Driver. Is it possiable to get similar current with DLPC3470+DLPA2005?

Or the firmware version is not correct? Because I tried on several different PCB and LEDs, the Maximun current is 1000mA aswell.

Could you give me some suggestions?

Regards!

over 3 years ago

0 Mayank Khandelwal over 3 years ago

TI__Genius 9971 points

Hello Mao,

Welcome to TI E2E forums and thanks for showing interest in the DLP technology. When you try to change the Max LED current settings via 5Ch command, have you verified this change by reading back the through 5Dh command?

Also, are you seeing the same behavior on DLP2010EVM-LC as well?

Regards,

Mayank

0 QI MAO over 3 years ago in reply to Mayank Khandelwal

Prodigy 20 points

Hello Mayank ,

Thanks for reply. I read back the current setting of my testing board through advanced tool in GUI , the current value are same as I set.

As the DLP2010EVM-LC has the current lint of 769mA, I didn't try to change the Max LED current on the EVM.

Regards,

Qi Mao

0 Vivek Thakur over 3 years ago in reply to QI MAO

TI__Mastermind 23070 points

Hello Mao,

Is your board design similar to EVM design? Are there differences especially RLIM values?

regards,

Vivek

0 QI MAO over 3 years ago in reply to Vivek Thakur

Prodigy 20 points

Hello Vivek,

Yes, it is similar to EVM board. RLIM parameters are: 0.039Ω ±1%, 1W, 1206.

And to verify my board, I tried use two of them in parallel connection. The voltage across these resistors is 39mV, thus current is 2Amp.

Is that means there is some limit in the firmware I am using?

Regards,

Qi Mao

0 Mayank Khandelwal over 3 years ago in reply to QI MAO

TI__Genius 9971 points

Mao,

Thanks for the information. Yes, there is a limit set in the firmware for the LED currents. But the commands that you were using should override those limits. I am verifying about this on our hardware and will get back to you in a couple of days.

Regards,

Mayank

0 Mayank Khandelwal over 3 years ago in reply to Mayank Khandelwal

TI__Genius 9971 points

Mao,

Are you still facing this issue related to max current limits?

Regards,

Mayank

0 QI MAO over 3 years ago in reply to Mayank Khandelwal

Prodigy 20 points

Hello Mayank ,

Yes, I am still facing the max current limits, have you got any result on the EVM?

Thank you.

0 John McKnight over 3 years ago in reply to QI MAO

TI__Expert 6880 points

Hello Mao,

Thank you for the feedback. It has been some time so the team will refresh itself on the matter and look into a possible resolution.

Have you tried a newer version of the FW? If you can test a newer FW version, can you report if Mayank's suggestion has worked?

Regards,

John

0 QI MAO over 3 years ago in reply to John McKnight

Prodigy 20 points

Hi John,

Yes, DLPA2005 + DLPC3470(dlpc3470_fw_8.0.0) + DLP2010LCFQJ+ LE B Q8WP, also give similar result. Trying to set current above 720mA will not rise the LED anode voltage on DLPA2005.

Regards,

Mao

0 Akhil Guntumadugu over 3 years ago in reply to QI MAO

TI__Expert 3825 points

Hi Mao,

Thanks for the information. Please wait a couple of days for us to share our observations on the EVM and help you.

Regards,

Akhil

0 Mayank Khandelwal over 3 years ago in reply to Akhil Guntumadugu

TI__Genius 9971 points

Hello Mao,

The DLPA2005 supports a LED current up to 2.4A and a max. LED forward voltage of 4.55V. Hence, you will have to pick a LED which has a forward voltage less than 4.55V otherwise the PMIC can not increase VLED far enough to get desired LED current.

Regards,

Mayank

0 Mayank Khandelwal over 3 years ago in reply to Mayank Khandelwal

TI__Genius 9971 points

Mao,

A couple of additional questions -

1. Is this behavior reproducible across multiple boards?

2. We suspect there might be some design issue in the feedback loop of DLPA2005. Can you compare your schematics with the EVM and if possible share the schematics with us.

Regards,

Mayank

0 QI MAO over 3 years ago in reply to Mayank Khandelwal

Prodigy 20 points

Mayank，

Thanks for reply, my question is:

The FWs we are using are based on 2010EVM，dlpc3470_fw_8.0.0 or dlp2010evm-lc_7.3.1 as attached below. Are there any limits on LED curent in these FWs as the LEDs on 2010EVM have 769mA current limit. Would you please test on you board with these FWs?

dlp2010evm-lc_7.3.1.img.zip dlpc3470_fw_8.0.0.img.zip

For your questions:

1. According to the LED Vf[V] vs If[mA] character, forward voltage @2A is about 3.0V.

2. Yes, we tried two different PCB layout, still got the same result?

3. Here is the PCB layout we test right now, schematic of feedback loop is same with EVM. Please check.

Regards,

Mao

0 Mayank Khandelwal over 3 years ago in reply to QI MAO

TI__Genius 9971 points

Mao,

We will get back to you with an update by tomorrow.

Regards,

Mayank

0 Mayank Khandelwal over 3 years ago in reply to Mayank Khandelwal

TI__Genius 9971 points

Mao,

After some experimentation and internal discussion with the team we could figure out that the current is indeed limited to 1A for DLP2010EVM-LC. Here the bottleneck in not the maximum current that DLPA2005 can supply. The current is limited to protect the DLP2010LC optical engine on the EVM.

Regards,

Mayank

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DLPA2005: Setting LED Current to 2Amp