MPS1474 DC DC Buck regulator design online error

DC-DC Power Converters
1

Hi. I am designing a DC DC buck regulator using MP1474S.

MPS have an online tool for designing buck regulator

These are my input specifications that I had given:
Vin= 8.4, Vin(min) = 7, Vin(Max)= 8.4, Vout= 6, Current= 2A, Switching frequency= 500khz, Inductor Current Percentage= 30, UVLO= 5.6V, High current transient= 2A, Low current transient= 1A,
R3/C6 Arrangement= A2

With these data, the online tool gave a schematic circuit in which I had got R4 to be 0 ohm. But how is that possible?

According to the datasheet of MP1474S, R4 should be nearby 16k as shown in the TYPICAL APPLICATION CIRCUIT of 5V,2A

Regards,

Nilotpal Baruah

#MPS1474 DC DC Buck regulator design

2

Hi Nilotpal,

The R4 resistor is for loop stability. A smaller RT value leads to higher bandwidth, but lower phase margin and could cause instability. This value can be adjusted for performance with your specs. For MP1474S, the T-type network is highly recommended when VOUT is low.

Best Regards,
Yu