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Hello,
I have measured efficiency of the whole driver I built (with R17=0R). The max efficiency is 82%. Comparing to WEBENCH results it is about 10% lower. Provided the input voltage is higher comparing to WEBENCH design (where Vin max = 40V), is there any chance to obtain better efficiency?
Tab 1
Vin (DC) [V] | Iin (DC) [A] | Pin [W] | Vout (DC) [V] | Iout (DC) [A] | Pout [W] | Efficiency [%] |
53.74 | 0.27 | 14.51 | 17.64 | 0.68 | 12.00 | 82.67 |
56.57 | 0.26 | 14.71 | 17.64 | 0.68 | 12.00 | 81.56 |
63.64 | 0.23 | 14.64 | 17.64 | 0.68 | 12.00 | 81.95 |
70.71 | 0.21 | 14.85 | 17.64 | 0.68 | 12.00 | 80.78 |
77.78 | 0.19 | 14.78 | 17.64 | 0.68 | 12.00 | 81.17 |
84.00 | 0.18 | 15.12 | 17.64 | 0.68 | 12.00 | 79.33 |
Fig 1
Fig 2 WEBENCH diagram
Fig 3 WEBENCH efficiency chart
Thanks.
Kind Regards,
Piotr
Yes, you are right. I should have isolated the converter first then measure the efficiency.
However, the currents of different parts of the whole circuit are as follows:
- dimming control <4mA
- 5V reg. 6mA
- LM3488 3mA
So, the power loss in those components should be: P = 17.6V x (4+6+3)mA = 0.23W,
where 17.6V is the output voltage of the converter.
I doubt that 0.23W taken by those components changes the efficiency significantly.