DRV8262EVM: How to decrease the temperature rise of the chip when driving TEC

Matthew Chen

Part Number: DRV8262EVM
Other Parts Discussed in Thread: DRV8262

Tool/software:

Hi- team,

My customer use DRV8262 to drive the TEC 12V@4A, they test it with our EVM. When drive 2 * TEC with 1 DRV8262 for about 30 mins(Line3 &4 in the table), the final temperature is about 55℃ under ambient temperature.

Consider the actual condition, the ambient temperature maybe 40-50℃, which means our device goes to 70℃.

1. Customer wants to make the temperature <60℃ without heatsink. Do you have any suggestion to solve it?

2. I find there are some vias under the chip in the EVM. Do we Resin Plug Hole or fill the hole with copper?

3. for the dead time of DRV8262, is it constant to be 300ns? Is there a way to adjust the dead time?

4 Do we have any TEC testing report using DRV8262 that can share with customer?

5 How to select the value of the capacitor on VM? Is there a formula that can refer to?

Thanks a lot

Matthew

9 months ago

0 Murugavel4637 9 months ago

TI__Mastermind 34915 points

Hi Matthew,

1. How are they driving the TEC? If they're using PWM what is the frequency used? Using higher frequency would increase switching losses and contribute to higher temps of the die.

Customer can also consider the DRV8262 DDV package option that has a lower Rdson hence will run at lower temperature. This package requires a top mounted heatsink and can support much higher currents compared to the DDW package of the same device.

2. These are through hole thermal vias. They're not plugged. The Altium project file can be downloaded from the web.

3. Dead time cannot be changed.

4. Please refer to this E2E post, https://e2e.ti.com/support/motor-drivers-group/motor-drivers/f/motor-drivers-forum/1327477/drv8262evm-driving-tec/5089396?tisearch=e2e-sitesearch&keymatch=DRV8962%25252525252525252520TEC%25252525252525252520current%25252525252525252520regulation#5089396.

5. Please see this application note, bulk capacitor calculation and output capacitor selection, https://www.ti.com/lit/an/slta055/slta055.pdf. These formulae can be used for calculation.

Regards, Murugavel

0 Matthew Chen 9 months ago in reply to Murugavel4637

TI__Intellectual 1340 points

Hi Murugavel,

Customer use 1khz PWM to drive the TEC and they do not want to add the heatsink in there system. Apart from decrease the frequency, do you have other suggestion to improve the thermal performance?

Matthew

0 Murugavel4637 9 months ago in reply to Matthew Chen

TI__Mastermind 34915 points

Hi Matthew,

1 kHz is pretty low and may not contribute much to switching losses. How is the TEC current regulated? Is it just set by duty cycle of the 1 kHz PWM? How's the output ripple to the TEC managed?

Reducing the VM drive voltage will help reduce the power dissipation. In addition if the air circulation around the PCB not adequate, especially around the bottom and top of the driver IC a small fan to force air circulation will help mitigate thermals.

Regards, Murugavel

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DRV8262EVM: How to decrease the temperature rise of the chip when driving TEC