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Hi Team,
The customer is experiencing below issue and needs your help.
The application circuit is shown in the figure above. DRV8844PWP is very hot when 24V positive and negative terminals are connected to VCC24V and GND respectively, so that GND_24V is floating. Observing the temperature with a thermal imager will rise in a straight line, with more than one hundred degrees. How is it caused?
Thanks.
Hi Annie,
It seems like the thermal pad GND and the other GND pins (6,9,14,28) are left floating. In order for the thermal Pad to dissipate heat, it has to have a return path to the main power supply GND. If you look at the layout example on section 10.2 of the datasheet (shown below), all the GNDs are connected to the bottom layer ground plane.
Hi Pablo,
Customer has following question need your help.
This is the circuit diagram of DRV8844 on the PCB. The main circuit ground (6, 9, 17, 28) is connected to the thermal pad. It is not excluded that the thermal pad PAAD at the bottom of the chip is not connected to the thermal pad on the PCB due to the manual soldering problem.
But as long as the pins (6, 9, 17, 28) are normally connected to the corresponding pads, they are connected to the PPAD. In addition, the signal ground LGND is connected to the other ground through three parallel capacitors. (The signal ground LGND in section 10.2 of the data sheet is directly connected to the PPAD, which is different from the one drawn by the customer.)
Customer question:
Is this the cause of the breakdown of the logic pin (The logic pins that are broken down may be different each time.) and the short circuit to ground?
Thanks.
