# Measurement of Quiescent Current and Operating Current in Gate driver

In datasheet they have provided two parameters named Quiescent Current and Operating current in which I am measuring quiescent current i.e, ground current flowing from the device VDD to GND , when device inputs (HI,LI) are grounded (test conditions as mentioned in datasheet.

I am measuring Quiescent current at 1 (VSS) for now from below figure, Or should I consider current at 2 (RT1 and RT2) so that it comes to Quiescent current= Current at 1 + Current at 2 ?

(RT bias voltage is 3V which is given internally)

Where should i measure operating current providing f=500KHz input?

This table gives operating current for 25 degree as 1.5mA

When I relate this to below plot which is w.r.t to temperature the operating current contradicts the table value.

Can anyone shed some light on these parameters measurements

## 1 Answer

I am measuring Quiescent current at 1 (VSS) for now from below figure, Or should I consider current at 2 (RT1 and RT2) so that it comes to Quiescent current= Current at 1 + Current at 2 ?

Carefully look at the subscripts of the parameters (underlined in red):

The current $$\ I_{DD}\$$ is the current that enters the $$\ V_{DD}\$$ pin and is therefore called "$$\ V_{DD}\$$ Quiescent current". So, you should measure this current at the $$\ V_{DD}\$$ pin.

Where should i measure operating current providing f=500KHz input?

Same as above, at the $$\ V_{DD}\$$ pin

This table gives operating current for 25 degree as 1.5mA
When I relate this to below plot which is w.r.t to temperature the operating current contradicts the table value.

Note that the table specifies a typical value. I would also expect this typical value in Figure 2, but probably they used a different measurement setup, yielding a different operating current than the typical value. (Note the same applies to $$\I_{HBO}\$$.)
It is not uncommon to find such a (seemingly) "inconsistency" in datasheets.

• Here is what I understood Quiescent Current and Operating Current is measured at VDD. But, how Operating Current calculated is it average current at VDD? – Adithya Pai Aug 22 at 7:01