I am using TPS5450 for 19V output with 3A load current. I have calculated the inductor value accordingly which comes around 1uH. Iam using shielded inductor from coilcraft. I have calculated the feed back resistors value according to the formula R2 = R1 * 1.221/ (Vout - 1.221) to set the output voltage to 19V.
Problem : When the input voltage is increased till 10 volt the output raises upto 6.7V and then it decreases when the input voltage is further increased to 25V.
My requirement is as follows :
1)Input voltage - 22.4V to 29.4V
Output voltage - 19.5V Output current - 3A
2)Input voltage - 22.4V to 29.4V
Output voltage - 19.5V Output current - 4.6A
3)Input voltage - 22.4V to 29.4V
Output voltage - 19.5V Output current - 4.6A
Kindly help to to design proper circuit using TPS5450
