# Op Amp Power Calculation I am simulating an op-amp circuit of which a small section is shown in the image. As per power consumption formula,

P = Icc * (V+ - V-) + Iout * (V+ - Vout)

I tried to calculate the power. I have put the values shown in the image.

P = 1.17mA (I have confusion in this value) * (5V-(-5v)) + 0.36 mA (5V-2.16V)

P = 11.7 mW + 1.0224 mW = 12.72mW. But the Watt meter probe in simulation shows 4.89mW .

I got a confusion that whether I am missing any point or doing wrong in the calculation?

Clarify this!

Power consumption of the op amp is different than the power drawn from the supply.

The equation below should give you the power consumed by the op amp I think.

ICC * VCC + IEE * VEE - I(OUT) * V(OUT)

• Tip: You can use HTML entities such as &times; ($\times$) and some markdown such as <sub>...</sub> and <sup>...</sup> for sub- and superscript. Feb 7 '20 at 20:47
• Thank you I was wondering how people were doing that Feb 10 '20 at 18:27

I'm confused by the various measurements - DC, p-p and RMS - but just working with the DC I get: 1. 5.5 mW is provided by VEE.
2. -0.49 mW is provided by VDC2. I'm not sure how a circuit could do this.
3. The output current is negative so the op-amp is sinking current so power out is -0.41 mW.

Adding them up I get PIC = PIN - POUT = (5.5 - 0.49) + (-0.41) = 4.6 mW.

That's the best I can make of it.