UCC28C42-Q1: Schematic for Review

Ajmal T

Intellectual 420 points

Part Number: UCC28C42-Q1
Other Parts Discussed in Thread: UCC28C42, LM5118, PMP10833

Hi,

Can any one help me for reviewing the schematic attached?5758.EFI Regulator.pdf

It is a design with buck and buck-boost converters using UCC28C42 PWM controller and LM5118 buck boost controller.

Please find the attached topology for your reference

Below is the requirement specifications,

Vin: 5VC-212VAC (from alternator)
Vin Frequency : 13.33Hz-300Hz
Vout: 14VDC
Maximum load: 6A
Isolation requirement : No

Below table shows the Input Vs Output characteristics,

Input Freq	Vin VAC	Vout VDC	IL (A)
13.33	9.40	14	0.80
20.00	13.50	14	1.40
26.67	17.50	14	2.00
33.33	21.90	14	2.40
66.67	47.00	14	5.00
100.00	76.50	14	5.00
133.33	94.20	14	5.50
166.67	122.80	14	5.50
200.00	141.80	14	5.50
240.00	169.90	14	5.50
266.67	187.90	14	5.50
280.00	197.20	14	6.00
300.00	210.90	14	6.00

Regards,

Ajmal

over 4 years ago

0 Teng Feng over 4 years ago

TI__Genius 13660 points

Hi Ajmal,

I advise to add a 0.1~1uF capacitor at REF pin.

But I don't think UCC28C42 can work normally in this circuit, because when PWM OUT is turned on (OUT pin), the GND of the chip is equal to V_OR_OUT, however V_OR_OUT is higher than VOUT_14V (VDD pin).

LM5118 is a not a device of HVP, can you create a new post for LM5118?

Regards,

Teng

0 Ajmal T over 4 years ago in reply to Teng Feng

Intellectual 420 points

Hi Teng,

Thanks for the feedback.

Noted the capacitor requirement at vref pin.

Please note that, the buck converter with ucc28c42 is the redesign of the TI reference design PMP10833.

Can you please check and confirm on the working.

I will open a thread for LM5118 schematic.

Regards,

Ajmal

0 Teng Feng over 4 years ago in reply to Ajmal T

TI__Genius 13660 points

Hi Ajmal,

Sorry for my mistake.

I understand this buck application now and it is good to me besides adding a capacitor at REF pin.

Regards,

Teng

0 Ajmal T over 4 years ago in reply to Teng Feng

Intellectual 420 points

Hi Teng,

Thanks for the confirmation.

The Capacitor value at REF is based on the switching frequency. 110kHz is the switching frequency opted (R=15.4kohm and C=1nF)

So if I change this value, it will change my Fsw as well. Can you please check it and suggest?

Regards,

Ajmal T

0 Teng Feng over 4 years ago in reply to Ajmal T

TI__Genius 13660 points

Hi Ajmal,

I was not saying the timing capacitor (CT), please see below figure.

Regards,

Teng

0 Ajmal T over 4 years ago in reply to Teng Feng

Intellectual 420 points

Hi Teng,

Noted it. Thanks!

Regards,

Ajmal

Power management

Power management forum

UCC28C42-Q1: Schematic for Review