LM76003-Q1: Schematic review

Hi

sure, can you provide input range and output voltage?

It looks you set at 400Khz with 5V output( the net name for TP300 is V12P0, but the FB resistor is 5V output setup), you can choose 10uH inductance with higher than 5A saturation current.  the output capacitor also need to be increased to 100uF-150uF. 

and it is better to add some electrical capacitor too.

Thanks

Hi,

I will ask the power supply designer these datas.

The output shall be 12V, so I think that the FB resistor couple is incorrect. I will let you know.

Baptiste

Hi Baptiste:

thanks, if 24Vin 12Vo, 15uH inductance will be recommend with 44uF-100uF output capacitance.

Thanks

Hi Daniel, 

Thanks for your reply,

I had feedbacks from the power supply designer:

• 12V is what we expect. R303 and R312 values have been inverted..
  • FB divider: R311 = 100K ; R312 = 9K09
  • EN divider: R302 = 100K ; R303 = 24.9K
• all calculation have been done with a 1.5MHz frequency in the DC/DC converter. So R304 will be updated to 24.9K. In this case, the inductor value seems ok, can you confirm ?
• Output capacitor: he calculate a 20mVpp output ripple with the 2*10uF capacitors which is enought for our design. Why more output capacitors?
• Output current: between 0.6A and 1.8A.
• Input voltage: arround 19V.

schematic update extract

Is it answering your questions ?

Do you have additional recommandations?

B.CHERDLE

Regarding input voltage, it is between 19V and 28V and can be up to  54V (in case of load dump). 

HI

I will suggest using L=6.8uH or 4.7uH for 19V-28V Vin, 

for output cap, 22uF output is fine, but cause most of ceramic capacitor will decrease by DC bias, so pls make sure the effective output capacitance under 12V is 22uF. The enough output capacitance can make the buck converter loop stable . 

Thanks