TPS40170-EP: Power management forum

venkatesh R

Part Number: TPS40170-EP
Other Parts Discussed in Thread: TPS40170, LM25148

Tool/software:

Hi Team ,

I am using TPS40170 for controlling TEC module ,currently I am controlling TEC by ON/OFF control ,byEN pin of TPS40170 .But with ON/OFF control Reliability of our application is affected .

So we want control the TEC Module by PWM control ,I read from datasheet that TPS40170 is PCM control buck controller, But I have a doubt ,In Which pin i have to feed the PWM signal ,

I need a help to design the PWM controlled buck controller using TPS40170 ,Input voltage is 24V and Expected output (1V-10V) using PWM control .

6 months ago

0 Taru Kapoor 6 months ago

TI__Genius 11815 points

Hi Venkatesh.

Can you share a block diagram of what you plan to implement?
If I understand correctly - you want to change the output voltage on the fly, right?
What is the output current required?

TPS40171 is a Voltage mode controller and not a peak current mode (PCM) controller. It generates a PWM signal to drive the FETs to do buck control (based on voltage mode control - see here to understand different types of buck control schemes: https://www.ti.com/document-viewer/lit/html/SSZTC38)

Also, is there a requirement of an 'Enhanced Product' -EP rated device? (The -EP that you see after the TPS40170 stands for Enhanced product - see https://www.ti.com/support-quality/certifications-and-standards/part-ratings.html). If not - you may want to consider one of newer devices like: https://www.ti.com/product/LM25148

Thanks,

Best Regards,

Taru

0 venkatesh R 6 months ago in reply to Taru Kapoor

Prodigy 30 points

Hi Taru ,

Can you share a block diagram of what you plan to implement?

Below is the high-level block diagram .I am using peltier cooling for laser diode .Instead of I ON/OFF driving .i am planning to drive using PID controller to maintain the stable precise temperature at Internal laser diode .to improve the reliability

If I understand correctly - you want to change the output voltage on the fly, right?

Yes ,your understanding is right

What is the output current required?

5A current at 10V .

0 Taru Kapoor 6 months ago in reply to venkatesh R

TI__Genius 11815 points

Hi Venkatesh,

In my opinion - the best way will be to use the DAC from the MCU - use the implementation similar to the one in this app note (https://www.ti.com/lit/an/slyt777/slyt777.pdf) See Pg. 4.

Also, if you do not need an Enhanced Product - use the LM25148 (https://www.ti.com/product/LM25148)

Thanks,

Best Regards.

Taru