LT8210 average current limit

Hi,

In the datasheet, I noticed the equation for I_limit is 1675/(R_Imon*Rsense2). It says that those 2 resistors set the average current limit, yet if I plug in the values for the circuits found under "typical applications," the current limit does not come out to the amperage spec'd at the output (i.e., page 38 shows 10A supply, but I_limit comes to 12.9A). Why are these values different?

I am wondering because I have a DC2814A-A demo board, and current at the output says 3A, but I_Limit comes to 6A and I don't see anything limiting my output current except the ferrite beads which are 2.5A.

  • 0
    •  Analog Employees 
    on Nov 9, 2020 4:24 PM 23 days ago

    Hello,

    My name is Chris Gass. I am the product application engineer for the LT8210. I also designed the DC2814A demoboard. 

    We designed both the circuits on the datasheet and the demo board to support, "at a minimum", at least as much current as rated. This means the circuit on page 38 will deliver at least 10 Amps and the demo board will deliver at least 3 Amps. The demo board is rated to 3 Amps continuous based on the thermal performance of the PCB. Figure 9 in the the demo manual shows the thermal performance. 

    Of course you are free to set the current limit lower closer to your desired limit. Please keep in mind that the current limit is a 'soft' limit. It will begin limiting current at about 93% (0.93V) of IMON, fully limiting at 100% (1.0V).

    Please let me know if you have further questions,

    Chris