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TPS51120EVM-001: Current mode configuration issue.

Part Number: TPS51120EVM-001
Other Parts Discussed in Thread: TPS51120

I designed a circuit around the TPS51120 for my 5V0 and 3V3 power source. I prefer the "current mode" as it has a low ripple.
The board wouldn't power up and now I'm trying to reproduce the same on the EVM.

I'm using the TPS51120EVM, and the configuration is as shown below.

Pin-Name-Connection

1 - VO1 - NC
2 - COMP1 - NC
3 - VFB1 - NC
4 - VREF2 - 2V0
5 - GND
6 - VFB2 - Wired to VFILT5. For default 3V3 output.
7 - COMP2 - RC to GND. (10K and 1nF)
8 - VO2 - Wired to Output (Ch2)
9 - EN5 - Floating. Enabled.
10 - EN3 - Floating. Enabled.
11 - PGOOD2 - Pulle dup to VFILT5 (100K)
12 - EN2 - Floating. Enabled
13 - VBST2 - 0.1uF cap to LL2
14 - DRVH2 - 5.1Ohms to High side gate.
15 - LL2 - Drain of Low-side MOSFET
16 - DRVL2 - Gate of the low side gate.
17 - PGNG2 - GND
18 - CS2 - 15mOhms sense resistor.
19 - VREG3 - NC
20 - V5FILT - 4ohms to VREG5 and 1uF to GND 
21 - VREG5 - 5V0 - 10uF to GND
22 - VIN - 12V. 1uF to GND
23 - CS1 - NC
24 - PGND1 - GND
25 - DRVL1 - NC
26 - LL1 - NC
27 - DRVH1 - NC
28 - VBST1 - NC
29 - EN1 - NC
30 - PGOOD1 - NC
31 - TONSEL - GND/VFILT5 
32 - SKIPSEL - GND/VREF2
33 - PwPd - GND

In the first step, I'm trying to generate the 3V3 output. I have an LED at the output. The VIN is 12V.
When in enable EN2, The LED just blinks. Probably goes into the fault condition. I read close to 4.65V when I set the JP2 to "Fault-Off" setting.

Is there a working reference design for the 5V0 and 3V3 in the current mode? Did anyone else have a similar stability issue? 
Any help will be greatly appreciated. 

  •  

    The first thing that I notice is your schematic is missing the high-frequency roll-off capacitor from COMP to GND (C15 on the EVM) which is required to roll off the high-frequency gain of the error amplifier.

    The second is to review the existing C14 / C15 / R20 compensation.  Section 7.4.1.1. goes step by step through the current mode compensation design process.