LM5170EVM-BIDIR: LM5170-EVM-BIDIR-Output Voltage Control-BOOST MODE

Hi Salman,

The configuration now will set output voltage to 50.5V.

1. I think the easiest way to change the output voltage with MCU is to change the voltage applied to pin3 of U2A. This voltage now is 2.048V and output voltage is proportional to this voltage.

2. You can change the value of R77 to adjust the output voltage. Vout=2.048V*(R75+R77)/R77

Best Regards,

Feng Ji

Hello Feng Ji,

1. How I change the pin3 voltage of U2A physically on the board?

Hi Salman,

You may change this voltage with a voltage source and a blue wire connected to this pin.

Best Regards,

Feng Ji

Hi Feng Ji

Thank you for the reply, I do not see any test point for connecting the voltage source to this point, should be tricky. 

Hi Salman,

Yes, you need to use blue wire.

Best Regards,

Feng Ji

Thank you Feng Ji

But do this reference voltage has any limit range, I want to give it 48V through DC supply.

Second, I want to confirm for boost operation I have short circuited the pads of the breakers, the copper wire I have attached can carry atmost 10A, my application is like for 5A maximum. so is it in a safe limit or it can make some damage if the outout current increases.

Hi Salman,

Please describe your request in detail. I do not know what you want to do with the EVM.

Best Regards,

Feng Ji

Hello Feng Ji

1. For a boost operation I have short circuited the breakers by soldering a copper wire on the pads but I am afraid that copper wire can carry 10A of current, Is that would be enough?

2. Second question was related to the voltage control when I am using the MCU, you have said change the reference voltage of IC U3A Pin 3, so it is now 2V, I want the reference voltage 48V, so can I give it through voltage source?

Hi Muhammad,

1. I would suggest to choose wire that is enough to carry your inductor current.

2. You can send a voltage Vref to U3A Pin 3 to adjust the output voltage. Vout=Vref *(R75+R77)/R77.

Best Regards,

Feng Ji