LM5050-1: LM5050-1

Hi Bosco,

Please share the waveforms and schematics.

Probe VIN1, VIN2, VOUT, GATE1, GATE2

Also, are you switching OFF second LM5050-1 or the second power rail? (50V)

Regards,

Shiven Dhir

Hi Shiven,

Thanks for the reply.

the voltages are as below.

VIN1(PS1)= 24V, VIN2(PS2)=50V, VOUT=50V, GATE1=21V, GATE2=21V

The first LM5050-1  OFF pin is grounded (always ON).

we are switching off the second LM5050-1 (3.3V is fed to OFF pin). 

When the second LM5050-1 is OFF. the output voltage should be 24V. But we are getting 50V

The Oring schematic was taken from the datasheet

Hi Shiven,

Oh. So then, to get my requirement, what is the way out?

Thanks

Hi Shiven,

Thanks.

Will LM74800 work for our requirement? (PS1=24V 30A, PS2=50V 30A.) PS1 should always drive the load, and when PS1 is off, then PS2 should take over.

how to achieve this using LM74800? pl., suggest

Regards

Hi Shiven,

Thanks. 

Hope this device(LM74800 ) will work for our requirement in Common Drain Topology.

also pl., suggest the mosfet that can be used (PS1=24V 30A, PS2=50V 30A.) 

Considering our req , what voltages to be set at the highlighted points

Also for handing high current can we have parallel mosfets?

kindly suggest.

Regards

Hi Shiven,

Was going through LM74900-Q1. is there a ref design for this device. showing power MUX in CD configuration?

pl., share

Hi Shiven,

if we want to monitor the current drawn by the both the  LM74900-Q1. when load is connected.

which is the best pin that can be connected to the MCU. (is it CS+ or IMON) ?

pl., guide

Hi

We are on local holidays and will get back to you on Monday.

Hi Shiven,

Thanks.

Have the following queries

We have decided to go with LM74910 with Priority Power MUX Common Drain and completed the design.
Have few quires which we are not clear.

1. In the VPRIM circuit, not sure how to connect the FLT, EN and SLEEP# pins

2. we are using 2 mosfets for the VPRIM and VAUX circuit and calculated Rsense is 1mohms. we have connected 2nos 2mohms making it 1mohms and the watt is 2W. is this ok. ?

3. In the VAUX circuit , we are not sure
   a. how to connect the SW,UVLO
   b. how to connect the FLT, EN and SLEEP# pins
   c. what is value of transistor is required at the HGate pin to drive the mosfet.

Please clarify.

Regards,

Hi Shiven,

Thanks for clarifying.

We have connected both the FLTB to VS pin . hope this fine.

Secondly, in the VPRIM circuit the connection for SW,UVLO,OV is as below.

in the VAUX circuit the connection for SW,UVLO,OV is as below.

Hope this is ok.?

Regards.

Hi Shiven,

Thanks for the support.

We have the below nets. is it better to leave the GND and AGND nets separate are do we need to tie them together?

Hi Shiven,

you mean to keep the net separate and dont connect them together? is our understanding correct?

Thanks, Shiven