LM74700-Q1: IC for Power ORing

H Jayaraj

Intellectual 600 points

Part Number: LM74700-Q1
Other Parts Discussed in Thread: LM74500-Q1,

Tool/software:

I am referring to two IC's --LM74500-Q1 and LM74700-Q1.

In the LM74700-Q1 datasheet it's application has Power ORing.

Which feature makes LM74700-Q1 to be used for power ORing?.

Can we use LM74500-Q1 for power ORing?.

What is the difference between those two devices?

In addition to that, Is it okay if enable(20V) comes before the input at ANODE?[Is it Failsafe?]

6 months ago

0 Shiven Dhir 6 months ago

TI__Guru 53385 points

Hi Jayaraj,

Reverse current blocking feature is used for ORing.

Hence, LM74500-Q1 can't be used for ORing.

It is safe to have EN high before ANODE. Sharing the abs-max table which states this.

Regards,

Shiven Dhir

0 H Jayaraj 6 months ago in reply to Shiven Dhir

Intellectual 600 points

Hi,

Let's say I am ORing the two supplies- One at 28V@5A(140W) and the other 20@5A (100W). Total of 240W output. As per datasheet output will take the maximum of two voltages i,e 28V. What will be my output current?. Is it 8.5A( 240W/28V)?. Will output take average current from each source?.

0 Shiven Dhir 6 months ago in reply to H Jayaraj

TI__Guru 53385 points

Hi Jayaraj,

I such case, your output current will be 8.5A. Highest voltage source will power the entire load.

Regards,

Shiven Dhir

0 H Jayaraj 6 months ago in reply to Shiven Dhir

Intellectual 600 points

Hi Shiven Dhir,

But, my 28V source can only give 5A.

0 Shiven Dhir 6 months ago in reply to H Jayaraj

TI__Guru 53385 points

Hi Jayaraj,

In that case, a stronger source needs to be used. Otherwise, the 28V source will get overloaded and start to droop.

Regards,

Shiven Dhir

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LM74700-Q1: IC for Power ORing