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| [SOLVED]How do I calculate the power dissipation for a ULN2003A Darlington array |
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| SlowBro:
How do I calculate the power dissipation for a ULN2003A Darlington array? Is it Vce(sat) * Ic? https://www.seeedstudio.com/document/pdf/ULN2003%20Datasheet.pdf |
| StillTrying:
Is it Vce(sat) * Ic? Yes, assuming they're fully switched on, the data sheet gives the typical saturation voltages 100mA to 350mA, 0.9V to 1.3V. ...add a few mW for the resistors and 1st transistor. |
| SlowBro:
So for example I want to using multiple channels drive 20 LEDs at 20mA each for 400mA total. Dissipation = 1.6V (max) Vce * 400mA = 640mW. Did I get that right? |
| StillTrying:
one of these channels drive 20 LEDs at 20mA each for 400mA total. I was going to say it might be a bit higher with 400mA though the one channel, 550 to 600mW, but you've already done it. Don't forget to add the other channels. I can't work out the Max. allowed dissipation from that data sheet. |
| SlowBro:
Yeah, all channels combined it will be pushing the Rth j-amb max but the on time will be brief so I feel comfortable about it. Thanks! |
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