Hi,
I probably will use the TPS6140 (boost converter) to generate 5V 1W (0.2A) from a single cell Li-Ion battery (4.2V down to 3.0V).
I'm trying to compute the inductor value that I need. Here is my design procedure :
- Efficiency estimation : n=88%
- Duty cycle : D=1-(VIN x n)/VOUT = 0.472
- Average inductor current : ILavg=IOUT/(1-D)=0.379 A
- Inductance value (dIL=0.2 x ILavg) : L=(VIN x D)/(dIL x fs)=5.34 uH
The problem is that the inductance is out of recommended value in the TSP6140 datasheet (1 to 2.2uH).
What should I do ?
P.S. Is there a tool for formatting equation in this forum ?
Best regards