LM5140-Q1: Request Reference Design File for Max 40A per CH.

Louis Han15

Genius 4680 points

Part Number: LM5140-Q1
Other Parts Discussed in Thread: LM5140RWGEVM

Hello

Webench Design support for Max 10A per Channel.

I want Max 40A per Channel

i Request Reference Design File or Schematic File for Max 40A per Channel.

Can you Design Support me Please?

Regards.

over 6 years ago

0 Samuel Jaffe over 6 years ago

TI__Mastermind 25590 points

Louis,

PMP15032 is a Reference Design for 45A (5.5-42VIN, 5VOUT)

-Sam

0 Louis Han15 over 6 years ago in reply to Samuel Jaffe

Genius 4680 points

Hi Sam

Thank your support.

VIN : 24V

VOUT : 12V

IOUT : 40A

Application : Motor Control

Can you recommend reference design for This Condition?

Regards.

0 Samuel Jaffe over 6 years ago in reply to Louis Han15

TI__Mastermind 25590 points

Louis,

I'm not finding a reference design for your specific condition. Your next option would be to use your requirements and go through the datasheet design requirements starting on page 27 of the datasheet. That will walk you through selecting the right components.

-Sam

0 Louis Han15 over 6 years ago in reply to Samuel Jaffe

Genius 4680 points

Hi Sam

Use Only one Phase.

Damage to device when connecting the Load

Check the Schematic Please.

Regards

0 Samuel Jaffe over 6 years ago in reply to Louis Han15

TI__Mastermind 25590 points

Louis,

1. The FETs on your schematic are only rated for ~9A. Is this schematic supposed to do 40A out?
2. Did you get this schematic from WEBENCH or did you follow the datasheet guide and make this yourself?
3. Have you made a board with this schematic? You said there is damage to the device so it sounds like yes. Can you describe more about the damage (how it fails, when it fails, if it is permanently damaged...).

-Sam

0 Ambreesh Tripathi over 6 years ago in reply to Louis Han15

TI__Expert 6860 points

Here are some reference designs which can be used in the application .
www.ti.com/.../pmp7819
www.ti.com/.../PMP10260

----Ambreesh

0 Louis Han15 over 6 years ago in reply to Ambreesh Tripathi

Genius 4680 points

Hi Sam
My Customer was Designed the this Schematic.
1. This Schematic Not 40A output so my customer will Change the FET.
2. LM5140RWGEVM Reference Schematic and Datasheet.
3. Made the Board this Schematic.
No Load - Normally Operate
Connect Load - Output Volt rises Linearly to input Volt(24V).
Finally Short Input and Output.

Regards.

0 Samuel Jaffe over 6 years ago in reply to Louis Han15

TI__Mastermind 25590 points

Louis,

The main differences between the schematic on the TI Design and your schematic are:

1. Sense resistor on TI Design has R28, R30, and C32.

2. Comp C25 is 47pF on TI Design but it's 10nF on your schematic.

3. HO2 and HOL2 on your schematic have resistors in the hundreds of ohms where TI Design is either 10 or 0.

Can you send waveforms of VIN, VOUT, COMP, high-side FET Gate, low-side FET gate, and SW2.

-Sam

0 Louis Han15 over 6 years ago in reply to Samuel Jaffe

Genius 4680 points

Hi Sam

Test Condition

Input Volt : 24V

Output Volt : 12V

No Load

Switching Freq : 22Mhz

High Side Gate Resistor : 700 Ohm(R165), 147 Ohm(R166)

Low Side Gate Resistor : 10 Ohm(R167), 10 Ohm(R168)

Waveform

Check the this Data Please.

Regards.

0 Samuel Jaffe over 6 years ago in reply to Louis Han15

TI__Mastermind 25590 points

Louis,

Change C96 to something around 100pF. 10nF is hurting your phase margin.
Try reducing the resistance on the high-side FET to something around 10 ohms.

-Sam

0 Louis Han15 over 6 years ago in reply to Samuel Jaffe

Genius 4680 points

Hi Sam

Check the Test Result Please.

C96 : 82pF

High Side : 10 Ohm(R165), 160 Ohm(R166 : Switch Voltage Swing the 30V when 10 Ohm)

Low Side : 10 Ohm(R167), 10 Ohm(R168)

No Load : Output Voltage the 12V.(Normal)

Load Connection : Output Voltage Drop the 2.5V or Device Short.

Regards.

0 Samuel Jaffe over 6 years ago in reply to Louis Han15

TI__Mastermind 25590 points

Louis,

Sorry for the delay. I'm thinking now the issue might be layout. Can you share the layout?

-Sam

0 Louis Han15 over 6 years ago in reply to Samuel Jaffe

Genius 4680 points

Hi Sam

Insert Layout File.

Please request the necessary data for check.

Regards.

0755.Layout.pdf

0 Louis Han15 over 6 years ago in reply to Louis Han15

Genius 4680 points

Hi Sam

Do you check the Layout file?

Regards

0 Ambreesh Tripathi over 6 years ago in reply to Louis Han15

TI__Expert 6860 points

Hi Louis ,

I looked into the Schematic and the layout and here are my suggestions :

1. As Sam mentioned replace R166 and R165 with 2.2 ohm or so . THe FET wont be able to turn on and off properly with this high value and that is what is reflected in your waveforms .
2. Are you trying to design 40A 2.2MHz design on single phase ? I would recommend you to design dual phase with switching frequency at 400KHz.
The current sense resistor used in the design is very small and any noise on the sensing line would impact the stability of the design . Use higher value resistor and add filter on sense line . Look into the EVM User'sguide for example www.ti.com/.../snvu499.pdf
3. The board's Layout needs to be changed . There is no Bypass cap placed next to High side Mosfet Drain to Low SIde Mosfet Source ie making bigger di/dt loop . Similar is the case of outloop from switch node to inductor to output cap to its return path .Please follow the layout mentioned in the datasheet/EVM user's guide .

---Ambreesh

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LM5140-Q1: Request Reference Design File for Max 40A per CH.