Hey guys,

I am building a circuit that has a gate driver powered by 2 lithium ion cells. My concern is that, if the gate driver is left connected to the batteries, is their a leakage current I should be worried about that may end up damaging my batteries if left too long? I am specifically using a tc4420 and the data sheet doesn't mention anything about a leakage current. Any input is helpful!

-khan

 

the data sheet doesn't mention anything about a leakage current.

It's given as the operating current as shown here:

So for minimum current you want the input be at 0V.
The maximum quiescent battery life would then be the Ah rating of the battery divided by 400μA.

 

It's given as the operating current as shown here:
View attachment 119226
So for minimum current you want the input be at 0V.
The maximum quiescent battery life would then be the Ah rating of the battery divided by 400μA.

Thank you for the clarification. Is there any way I can limit this to near near zero at zero volts Vin. I am basically trying to make a circuit soldered together that shouldn't be touched. I am wondering how they do this with battery powered devices without letting the battery discharge to a level harming the battery?

 

Is there any way I can limit this to near near zero at zero volts Vin

You need to remove the power to the circuit by some method.
What is the rest of the circuit doing when this IC is not being used?

 

You need to remove the power to the circuit by some method.
What is the rest of the circuit doing when this IC is not being used?

It doesn't seem like I can do that. Though I am open to methods to possibly do that as I am still learning. I will post my circuit soon. Rather, are there any gate drivers out there that have much lower leakage current? Say 20 microamps? The driver is driving a very low power mosfet that switches no more than 3 amps at 5 volts.

 

What is the MOSFET and how fast do you need it to switch?

 

What is the MOSFET and how fast do you need it to switch?

Very slowly. In fact switching is maybe once a minute. The mosfet is irf3205.

 

So, for that slow speed, you don't need a driver.

But that MOSFET needs 10V to fully turn on, and assuming each cell is 3.7V, you only have 7.4V total.
You should really have a logic-level type MOSFET whose Rds(on) in the data sheet is specified at a Vgs of 5V or less.
The irf3205. is specified at a Vgs of 10V.


But for low currents you may be okay.
How much current do you need to switch?
What signal level is controlling the MOSFET?

 

What signal level is controlling the MOSFET?

And what else is in the circuit that is "leaking" or otherwise consuming current?