Other Parts Discussed in Thread: LM5088
Hello,
I am using LM5088-1 device in one of my project for the input range 30V - 60V and Output voltage 12V/5A. The basic schematic is generated using the Webench Power design tool for the specification defined.
The observation is described below:
For the input voltage <38V and a 10R output load, the device is able to maintain the output power. But i see there is temperature raise for this 20% load current.
For the input range > 38V and 10R output load, the device output voltage significantly drops to ~4.5V
Below is the schematic for your reference, I have verified the schematic and the component values several time and also verified with the calculator provide for the LM5088 device.
In the above schematic and replace the Cdith = 100nF, Ccomp = 270pF, Chf = 47pF. Also the behavior is same with the values shown in the schematic
Below is the layout for the above schematic : Top layer
Layer 2:
Layer 3:
Layer 4:
Layer5:
Bottom Layer:
I see if current sense if hitting the limit, I have reduced the current sense resistor to 7.5mR and also shorted directly to ground. But the behavior is not positive.
Also tide the Css and Rt GND connection directly to IC Gnd pin using a jump. I understand the jumper wire would not so effective can misbehave sometime, expected at least some improvements if this is a issue. But no luck .
I have captured the waveforms on the SW node and the output, but no able understand the behavior of the device operation:
SW at Input voltage 35V @ 10R load
SW node with input voltage VIN = 45, VOUT = 11.15V @ 10R Load
VIN = 50, VOUT = 5V @ 10R Load
Request TI experts and other members in this community to suggest on how to resolve issue at the earliest.
For any more information feel free to ask me
Regards,
Anand M
