WEBENCH® Tools/LM3464A: LM3464A

Steven Spencer2

Part Number: LM3464A
Other Parts Discussed in Thread: UCC28740, LM3464

Tool/software: WEBENCH® Design Tools

To whom it may concern, I am using the LM3464A LED driver to power a series of LED. I am utilizing all 4 output of the driver. I am trying to design a power supply using the webench software that can handle my requirments. I have a forward voltage for the series LED (1 out of the 4 channels) that has a forward voltage of 64 volts. The average LED operating current is 700mA. I have attached the power supply that was generated in WEBENCH. Will this work with the driver for all 4 channels or is the power supply output current to small? Does the power supply output current have to be 700mA x 4 = 2.8A at minimum to drive all four channels each at 700mA?Draft1_PowerSupply.pdf

over 4 years ago

0 Sean Zhou over 4 years ago

TI__Mastermind 22745 points

Hi Steven,

So it seems that you are not using the LM3464 for your schematic? Does it seem that you have some questions with the UCC28740 from your attachment?

Sean

0 Steven Spencer2 over 4 years ago in reply to Sean Zhou

Intellectual 380 points

Sean, thank you for the reply. So I think there is some confusion from my first message. What I have attached in the previous email is the power supply that was generated in webench. That is what I am considering using as a power supply. However, the driver that the power supply in the picture will be attached to is the lm3464. I am wondering if the design generated by webench could meet my needs outlined in the previous email. I am trying to avoid having to design a custom transformer. I am simply wondering if the power supply design will be able to meet the requirments of 4x700mA output current needed to drive the lm3464 led outputs. Please let me know if that makes sense, if not please let me know what is confusing so I can clarify my question ad I need a solution as soon as I can have one. I appreciate the help!

0 Sean Zhou over 4 years ago in reply to Steven Spencer2

TI__Mastermind 22745 points

Hi Steven,

Could you share with me the clear block diagram of your system? I'm still not very clear about your requirement. Thanks.

Sean

0 Steven Spencer2 over 4 years ago in reply to Sean Zhou

Intellectual 380 points

I will provide that soon. I having an issue with posting another question on here. So I am asking you here. Does the thermal foldback feature have to be used or is it required for the DHC?

0 Sean Zhou over 4 years ago in reply to Steven Spencer2

TI__Mastermind 22745 points

Hi Steven,

You cna disable this function by the regs if you don't need such kind of function.

Sean

0 Steven Spencer2 over 4 years ago in reply to Sean Zhou

Intellectual 380 points

Thank you Sean, what do you mean by Regs? I am sorry I dont understand what you mean. Could you clarify what you mean?

0 Sean Zhou over 4 years ago in reply to Steven Spencer2

TI__Mastermind 22745 points

Hi Steven,

I'm sorry that I have mixed two question's answer, the thermal foldback function can't be disabled.

Sean

0 Steven Spencer2 over 4 years ago in reply to Sean Zhou

Intellectual 380 points

It is okay! I am wondering if it is at all possible to maybe have a 1 ohm resistor in place of a thermistor in order to constantly be operating in a voltage that does not trigger the thermal foldback?

0 Steven Spencer2 over 4 years ago in reply to Sean Zhou

Intellectual 380 points

Sean, I have an additional question to the one below. I am purchasing the eval board. If I wanted to see how it operates at driving a higher current load would I just need to change Rsense? Obviously I would not exceed power by driving to much on the load. What are your thoughts?

0 Sean Zhou over 4 years ago in reply to Steven Spencer2

TI__Mastermind 22745 points

Hi Steven,

Yes, you need to adjust the Rsense for higher output power and please refer to the application section for modification guideline.

Sean

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WEBENCH® Tools/LM3464A: LM3464A