MP2480 Temperature issues


I designed a LED driver with the MP2480, with the following specs:

Vin: 24V
Vout: 20V (6 LEDs @3.3V)
Iout: 2A
Inductor: 47uH @3A

FR-4 board, with vias and solder mask free area under the IC. Under operation, the IC temperature reaches 110°C (measured with a thermocouple at the area under the chip).

Increasing the inductor value would help reduce the temperature? What can be done?


Well have you tried using a larger inductor? What diode are you using for a catch diode? The data sheet doesn’t provide much guidance, but I would be using a 30V 3A Schottky type .
This design should be workable.

Plus there is this

External Bootstrap Diode
An external bootstrap diode may enhance the
efficiency of the LED driver. For the cases listed
below, add an external BST diode is from a 5V
rail to the BST pin:
z There is a 5V rail available in the system;
z VIN ≤ 5V;
z 3.3V < VOUT < 5V;
Add a diode for high duty cycle operations
(when VOUT/VIN > 65%), and for very-high–

from the datasheet

Thanks for the reply.

Yeah, I saw that in the datasheet but for some reason the duty cycle case slipped my mind.
I´m gonna add the diode and check if it helps.

Another thing I noticed is related to the solder paste: in a second board, with exaclty the same circuit and components, the MP2480 does not heat up as much, in the same conditions and same LED string. I think the solder under the IC is better in this case, maybe there was more solder paste, I don´t know, will investigate that too.