LT8410-1 Booster Circuit Current Draw

Hi,

I'd like to get some support regarding Linear's LT8410-1 boost converter. 

More specifically I am measuring a large disrepancy between simulated current consumption (using LTspice) and the reality of my circuit. 

To be more precise the boost converter is set to convert about 3.4V to 13.25V or 26.5V. I am measuring about 150uA current drawn from my supply in the first case and about 3mA in the second case. LTspice simulates an average current draw of ~130uA in the first case and about 250uA in the second case. 

The situation is a bit more complicated but I would like to discuss this in private if possible with one of the support engineers.

Thank you for any support.

Parents
  • Hello Dulcevida,

    Thank you for your reply. 

    I selected LT8410-1 in the first place because of its 8mA current limit. I am only using a very small battery and would not like to drain it more than 8mA at anytime for the booster (since there are other loads on it).

    I don't think that using the LT8410 will have much different results. Response time will be better but I am not sure that consumption will be lower. The LT8410-1 does exactly what I need it to do. It has great response time and very good load and line regulation. My circuit does reach 105V from 3.4V which is also great. Also at 50V output the bench measurement matches simulation. 

    The question is very simple:

    the graph above shows the simulated final output voltage at 105V and the average battery draw at 308uA. The load is 4uA @105V.

    My bench measurement shows current draw of about 3.5mA. 

    The simulated switch voltage with no load can be seen below. The OFF time is about 830nsec:

    The actual bench measured switch voltage (blue trace) with no load can be seen below:

    The OFF time is more than a microsecond and switching frequency is less than a MHz. It looks to me that the part is operating in the discontinuous mode. 

    All of the above seem to be very consistent with the datasheet. Hence, either my circuit/layout has some other fault or the simulation is not reliable or the datasheet has some problematic information.

    Which one is true?

Reply
  • Hello Dulcevida,

    Thank you for your reply. 

    I selected LT8410-1 in the first place because of its 8mA current limit. I am only using a very small battery and would not like to drain it more than 8mA at anytime for the booster (since there are other loads on it).

    I don't think that using the LT8410 will have much different results. Response time will be better but I am not sure that consumption will be lower. The LT8410-1 does exactly what I need it to do. It has great response time and very good load and line regulation. My circuit does reach 105V from 3.4V which is also great. Also at 50V output the bench measurement matches simulation. 

    The question is very simple:

    the graph above shows the simulated final output voltage at 105V and the average battery draw at 308uA. The load is 4uA @105V.

    My bench measurement shows current draw of about 3.5mA. 

    The simulated switch voltage with no load can be seen below. The OFF time is about 830nsec:

    The actual bench measured switch voltage (blue trace) with no load can be seen below:

    The OFF time is more than a microsecond and switching frequency is less than a MHz. It looks to me that the part is operating in the discontinuous mode. 

    All of the above seem to be very consistent with the datasheet. Hence, either my circuit/layout has some other fault or the simulation is not reliable or the datasheet has some problematic information.

    Which one is true?

Children
No Data