Part Number: LM3150
Tool/software: WEBENCH® Design Tools
Hi,
I am trying to create a design with the LM3150 that has Vin=24-28V and Vout=8V@3A. WEBENCH will create a design for this just fine but when I try and validate it against the datasheet formula there seems to be som discrepancy. Specifically I use Equation 60 and 61 to calculate Ron using the selected switching frequency of fs=530e3
Rond=-(8-1)*(24*16.5+1000)-1000=-10777
Ron=(24*8-8)/(24*100e-12*530e3)-10777=134k
The value in the WEBENCH design is 127k, either way when looking at Figure 15, this does not seem to fit any of the curves shown there, even when interpolating the values. The nearest curve with Ron=115k, has Vout at about 11V for for an input of 24V. Am I interpreting this figure correctly?
Also, the estimates for the minimum Cout and Cin are far greater the those given in the WEBENCH design.
I don't know whetjer to abandon this controller for this application or just believe the WEBENCH design, can someone help? Thanks.
Mike