LM7481-Q1: Oring Design

Xiaowei Zhang

Part Number: LM7481-Q1

Tool/software:

Hi team,

My customer are using LM74810 for their project, SCH as attached: VBAT_ORing_0710.pdf

They asked if consider the condition that 2 input are alive at the same time, can they remove the D245, D246 and connect the 2 VBAT_MCU_12V0 net directly? Will this have side effect to Q32/Q92 and oring function?

If EN is 3.3V and VBAT exceeds the OV threshold, HGATE will pull low and turn off Q2, right? Will DGATE pull low and turn off Q1 in this condition?

Best Regards,

Xiaowei Zhang

2 months ago

0 Shiven Dhir 2 months ago

TI__Mastermind 48575 points

Hi Zhang,

EN high and OV high will only pull HGATE low.

For diodes, why do you want to connect common drain points together anyways. Be it with or without diodes

Regards.

Shiven Dhir I iwo

0 Xiaowei Zhang 2 months ago in reply to Shiven Dhir

TI__Expert 3805 points

Hi Shiven,

Shiven Dhir said:
For diodes, why do you want to connect common drain points together anyways. Be it with or without diodes

Customer want to saving 2 diodes due to the cost. So can they connect the net together?

Best Regards,

Xiaowei Zhang

0 Shiven Dhir 2 months ago in reply to Xiaowei Zhang

TI__Mastermind 48575 points

Hi Zhang,

I understand the cost saving. I am trying to understand that why we need to connect them be it with or without diodes?

Also, during ORing, the common drain points are connected via this path all the time, hence I am unsure if seprataly they need to be connected together.

Regards,

Shiven Dhir

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LM7481-Q1: Oring Design