# Quiescent current of Battery charger IC

#### Mahantesh Teli

Joined Apr 2, 2016
21
Hi,
I want to understand how quiescent current is measured Ex Dc Dc battery charger IC, if Iq is 1.5mA during charge mode; Does this mean 1.5mA, device will consume per hour? Or how. ?

Plz educate me.

Thanks

#### Ylli

Joined Nov 13, 2015
1,030
1.5 mA is not a quantity, it is a rate. The IC draws 1.5 mA to power it's internal circuits.

#### Mahantesh Teli

Joined Apr 2, 2016
21

#### #12

Joined Nov 30, 2010
18,217
to be clear on this. You meant IC draws 1.5mA of current per hour.
No, it draws 1.5 milliamp hours per hour.
1.5 ma x 1 hour = 1.5 ma-hours

What if battery contains 1000 MaHr?
Then 1000 MaHr/1.5 MaHr = 666.66 hours.

#### Mahantesh Teli

Joined Apr 2, 2016
21
No, it draws 1.5 milliamp hours per hour.
1.5 ma x 1 hour = 1.5 ma-hours

What if battery contains 1000 MaHr?
Then 1000 MaHr/1.5 MaHr = 666.66 hours.
Battery is : Li-ion, 550mAh.

#### #12

Joined Nov 30, 2010
18,217
Thank you... can you please educate me how does Iq matters to battery charger IC.
Iq doesn't relate to anything important unless you are charging one battery with another battery.
The Iq comes from the wall outlet and the battery never knows about it.

#### Ylli

Joined Nov 13, 2015
1,030
Hi Ylli,

Thank you , to be clear on this. You meant IC draws 1.5mA of current per hour.
NO. It draws 1.5 mA of power. If it is turned on and allowed to draw that 1.5 mA for a hour, then it has used 1.5 mA-hr of energy. If it is on for 100 hours, then it will have used 150 mA-hr of energy.

That 1.5 mA is a rate, not a quantity. 1.5 mA is equivalent to about 9.3 x 10^15 electrons/second.

#### Mahantesh Teli

Joined Apr 2, 2016
21
Iq doesn't relate to anything important unless you are charging one battery with another battery.
The Iq comes from the wall outlet and the battery never knows about it.
But when the application is small power bank applications then ?

#### Mahantesh Teli

Joined Apr 2, 2016
21
NO. It draws 1.5 mA of power. If it is turned on and allowed to draw that 1.5 mA for a hour, then it has used 1.5 mA-hr of energy. If it is on for 100 hours, then it will have used 150 mA-hr of energy.

That 1.5 mA is a rate, not a quantity. 1.5 mA is equivalent to about 9.3 x 10^15 electrons/second.
Thank you Ylli: )

#### Mahantesh Teli

Joined Apr 2, 2016
21
Iq doesn't relate to anything important unless you are charging one battery with another battery.
The Iq comes from the wall outlet and the battery never knows about it.

Thank you: )

#### #12

Joined Nov 30, 2010
18,217
But when the application is small power bank applications then ?
Then the contributing battery has to pay the cost of the Iq.
The receiving battery never knows about Iq.