Hi guys,
I want to compare a PWM from [0-5V] to a voltage reference of 2V. I want the output of the comparator to be offseted to the following voltage [5-12]V so I' planning on putting the Vss pin to 5V and the Vdd pin to +12V. That way, a low level would give me 5V and a high level would give me 12V.
Can you confirm that I could use the LM2903BQDRQ1 with two different voltage supplies and no ground please?
Hi Amine,
Thanks for your post. This is an interesting use case. Unfortunately, this would not work because the input voltage range is defined by the VDD and VSS pins. Powering the comparator with 5V at VSS and +12V at VDD would mean the input range is only 5V to 10V so both of your inputs would violate this range.
Can you tell me more about your system needs and application? What is the comparator driving? There are some tricks you could do to achieve the 5V-12V output levels. One way is to create a resistor divider on the output and using the output of that divider to drive the downstream device. Another way is to use a transistor to level shift between the 5V and 12V. The comparator is operated at 12V single supply in both of these methods so that the input can be within the input voltage range. Please see below for the tina circuits.
