Hi everyone ,I am working on a custom PCB using the TI LM5170QPHPRQ1 as a single-channel buck converter. The design converts 30V input to 12V output at 5A. I am using only Channel 1 ,Channel 2 is unused. Despite trying many fixes the IC is not switching and I am not getting the output voltage please help to make this IC functional below is specifications of the IC .
VIN = 30V (Port A)
VOUT = 12V (Port B)
I_fullscale = 5A
Duty cycle = 12/30 = 0.40 (40%)
f_sw = 100kHz (RT = 40kΩ to GND)
VCC / VCCA = 10V
Mode = Single channel buck (Ch1 only)

Current pin voltage readings

Pin	Measured voltage	Expected	Status
VCC	10V	8–14V	OK
VCCA	10V	8–14V	OK
OVPA	0.88V	<1.185V	OK
OVPB	0.11V	<1.185V	OK
BRKG	12.2V	~VCCA+SW	OK
BRKS	6.14V	~VCCA+SW	Asymmetric
HO	4.8V static	Switching	Not switching
LO	0V	Switching	Not switching
SS	0V	0→1.185V ramp	Never charges
COMP	0V	1.5–2.5V	No voltage
OSC	1.18V	~1.185V	OK
ISENA+/−	4.5V both	Equal (no current yet)

Component values used

RT (OSC) = 40kΩ → 100kHz confirmed from datasheet
SS capacitor = 1µF to AGND
Inductor = 15µH per phase (PQ2614BLA-150K)
Sense resistors = 5× 1mΩ in series = 5mΩ total per phase
OVPA = 120K ohm
OVPB = 120K ohm
COMP network = R=10kΩ, C1=10nF, C2=0.1µF (topology under review)
ISETA = 1.1V DC applied
EN1 = 3.3V (HIGH) ✓
EN2 = GND ✓ (Ch2 disabled)
DIR = HIGH ✓
ISETB = GND ✓
IOUT1,IOUT2 = 5.22V
FAULT = HIGH (10kΩ pull-up to VCC) ✓

 

Hi Md,
Do you have a circuit diagram to post?
E

 

Hi Md,
Do you have a circuit diagram to post?
E

Yes please find the attachment in which the texts written in blue color are the pins voltage

 

After carefully examining the circuit, my GUESS is that there is a control input that is not being given the correct command. Nothing clearly marked "enable" but several connections that could be that function given a different name.
SO it is time to read the whole data sheet cover to cover.