Can you recommend a suitable circuit for a switching power supply that will power a compressor motor? Input from AC transformer 15 V, output buck 12 V/≥15 A for a 120 W compressor (start-up peaks 20–30 A).

List of components:

• BR1 KBPC3510, 35 A/1000 V bridge
• NTC1 MF72-5D9 (or 8D-11); K1 12 V relay (NTC bypass)
• C1,C2 22,000 µF/35 V low ESR; C3 10–22 mF/35 V
• TVS SMBJ30A (input), SMBJ18A (output)
• U1 LM5116 (HTSSOP‑20 EP)
• Q1,Q2 MOSFET 60 V, low RDS(on) (e.g. IPT007N06N)
• L1 8.2–10 µH / ≥30 A (SER2918H‑682)
• RS 3.3 mΩ/≥3 W (4‑terminal, parallel 3×10 mΩ)
• CIN 4×470 µF/35 V + 4×2.2–4.7 µF/50 V X7R
• COUT 3–4×820 µF/16 V polymer + 3–4×22 µF X7R
• RT 21 kΩ; CSS 0.22 µF; CRAMP 820 pF (C0G)
• COMP 18 kΩ + 3.3 nF // 330 pF; FB 88.7 kΩ / 10 kΩ + Cff 1 nF
• F1 ATO 15 A
• C_LOAD 2×1000–2200 µF/16 V (for compressor)

 

Where is the details for the compressor motor?

 

Where is the details for the compressor motor?

It is a standard 12V 120W refrigerator compressor. I was told that the short-term peak current can be up to 35A.

 

Short term or long term, the SMPS requires to convert the full load.
Perhaps your best bet is to bypass the SMPS during the startup period, with a couple of diodes in the bypass path to drop the voltage to 13.5, which the compressor should handle without problems. Then after a few seconds switch to the SMPS.

 

Why is the output just 5V and almost no current?

 

Exactly what is this doing?

 

See the "Figure 7-1. 5-V 7-A Typical Application Schematic" in Data Sheet PDF file. PDF page 21.

 

That is not what is actually shown in figure 7.1.
But since you don’t care to check your own errors, even when they have been pointed out, I am bailing out of this thread.

 

Sorry, I overlooked it. You are right.

I have tested the example in TINA-TI simulator which will give 12V 5A on the output at Vin 50V. Need to modify it to output 12V 20A and Vin 15V.