Hello MPS expert,
I just bought some parts of the MP9488 for the design of a power supply for 5.0VDC / 300mA output and 7.5VDC up to 80VDC input with the smal PCB possible.
A) what is the minimum voltage at the input to keep the MP9488 with the output current at 300mA?
B) what is the suggestion for input to go down to 6.5VDC and keep 5.0VDC at the output?
C) If the current rises above 300mA, would there be any over current protection?
Thanks in advance,
Hello MPS expert,
Welcome to our community.
Can you please share the Inductor value that you are using for the power supply?
The Fixed inductor Wurth WE-PD2 HV 7850 1200uH .28A 4.5 Ohm
Mouser code 710-768775312
Also what are the two diodes D1 and D2 used and the Vcc cap and the feedback cap (C3 and C4) used?
D1 = USB260-E3/52T
Mouse code: 625-USB260-E3
D2 = STPS3150U
Digikey code: 497-6583-2-ND
C3 = CAP CER 2225 220NF 500V X7R 10%
Digikey code: 399-16824-2-ND
C4 = CAP CER 2.2UF 100V X7R 1812 10%
Digikey code: 399-16352-2-ND
VCC Cap used is 10uF/25 common electrolytic
As I already had these pieces, I used them, but I know I could use better ones.
I did simulation for the 5V output of the MP9488 . Based on the simulation result output below are the answers to your questions:
A)what is the minimum voltage at the input to keep the MP9488 with the output current at 300mA? - Minimum Input voltage is 24V to keep the 5V load current at 300mA.
B) what is the suggestion for input to go down to 6.5VDC and keep 5.0VDC at the output? - The minimum voltage with 30mA of load ( 10% of 300mA) is 17V. Any lower input voltage will not be able to regulate 5V .
C) If the current rises above 300mA, would there be any over current protection?- Yes there is current limit on the Mosfet inside the MP9488. This peak current limit is 780mA. The nominal short circuit point (SCP) is 900mA (nominal) and 1200mA (max limit) .