UCC283: PLPT9 Laser compatibility

Art Mecina

Part Number: UCC283

Hello Guys,

Good day.

Our customer is looking to use UCC283 for their application. Basically it will be a power supply of 9V then the laser after that would be the UCC283 chip.

He has concerns because he needs 2.5A. Will the PLPT9 laser appropriate for UCC283? Below is the datasheet.

PLPT9 450LA_E_EN (3).pdf

Thanks!

Art

over 4 years ago

0 Juliette over 4 years ago

TI__Mastermind 18466 points

Hi Art,

I will look into this and will follow up tomorrow.

Best,

Juliette

0 Aaron Paxton over 4 years ago in reply to Juliette

TI__Expert 5605 points

Hey Art,

Can you clarify the power topology? What is the input voltage to the LDO?

Thanks, Aaron

0 Art Mecina over 4 years ago in reply to Aaron Paxton

TI__Genius 16795 points

Hi Aaron,

Customer plan to use 9V power supply. He believe the device will regulate the voltage to 4.3 to laser diode.

Thanks!

Art

0 Juliette over 4 years ago in reply to Art Mecina

TI__Mastermind 18466 points

Hi Art,

Is the current (2.5A) a continuous output or is it a max current.

If it is a continuous current, that is a lot of power dissipation on the part of the LDO and this will trigger a thermal shutdown. [meaning this part is not suitable for this design]

If it is a max current, do you know how long those events will last? (Ppulse in the data sheet)

Best,

Juliette

0 Art Mecina over 4 years ago in reply to Juliette

TI__Genius 16795 points

Thanks Juliette!

I'll let you know as soon as I have the answer to your inquiries.

Art

0 Juliette over 4 years ago in reply to Art Mecina

TI__Mastermind 18466 points

Thank you.

Best,

Juliette

0 Art Mecina over 4 years ago in reply to Juliette

TI__Genius 16795 points

Hi Juliette,

To answer your question, yes is a pulse thru the product ever say two minutes or more. Furthermore, customer is planning to have two LDO's in the circuit same configuration but in series to divide the voltage to about 4Volts. Just to be safe they are planning to include a fan to cool down the circuit.

Let me know what you think.

Thanks!

Art

0 Juliette over 4 years ago in reply to Art Mecina

TI__Mastermind 18466 points

Hey Art,

do the pulses last 2 minutes, or do they happen every 2 minutes for an unspecified amount of time?

if so, would you know how long those pulses last?

Best,

Juliette

0 Art Mecina over 4 years ago in reply to Juliette

TI__Genius 16795 points

Apologies for the late response Juliette. The pulses are less than 2 minutes.

Thanks!

Art

0 Art Mecina over 4 years ago in reply to Art Mecina

TI__Genius 16795 points

Hello Juliette,

Just like to update regarding this.

Best regards,

Art

0 Juliette over 4 years ago in reply to Art Mecina

TI__Mastermind 18466 points

Hi Art,

Sorry about that, it seems I wasn't getting notifications for this thread.

Looking at the datasheet's thermal design specs:

The pulse power would be defined as: [the equation on the datasheet seems to be wrong]

PPulse = Ppeak*dutyCycle

Given:

Vin = 9V

Vout = 4.3V

ICL = 2.5A

[I need clarification on the waveform of the pulses]

tON = 2 minutes (?)

tOFF = 2 minutes (?)

Answer:

PPulse = 5. 875 Watts

Thermal Resistance of device is 60C/W

PPulse*ThermalResistance = 352.5C

This means that you would see a rise of 352.5C due to the pulse length, automatically triggering thermal shutdown - which would cause the part to oscillate.

However if your TON time is actually in the range considerably smaller than minutes, this may be a suitable part [meaning the duty cycle value is a small fraction, thereby reducing your average pulse power].

Best,

Juliette

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UCC283: PLPT9 Laser compatibility