IC relay?

KMoffett

Joined Dec 19, 2007
2,918
VDD in your schematic is 5VDC. Do you mean that the "input" is pin 9 (Vcc) of the ULN2003? The ULN2003 is an open collector driver...basically an inverter. It's intended to pull a load, attached to Vcc, to ground when the logic input is high (5VDC).

Ken
 

Thread Starter

rubicon99

Joined Apr 19, 2012
46
Oh sorry, there is a voltage regulator that will drop the input voltage from 12-24 to 3.3 volts this power the microcontroller and other ics. Yea we would reverse the logic, If you give a low to the uln2003 in our design it will give you a high of the common since there is a pullup. but attached to a load will drop the voltage.
 

KMoffett

Joined Dec 19, 2007
2,918
This seems like a strange way to drive the output load. In order to pull the load up to near the VCC, the pullup resistor would have to be significantly lower resistance than the load. And when it's pulled low will draw a great deal more current than the load. Can you sketch a schematic of output load with voltage and current requirements?

Ken
 
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