I am trying to work out how the RefOut and RefAdj pins of the LM3914/15 work. These chips are so old I am sure they are explained in "101 courses".
But here goes. There is a fixed voltage drop between RefOut and RefAdj of 1.25V. In addition there is a 80uA (nominal) current through RefAdj to ground.
The closest I could emulate it is shown here but it is not correct. The current flowing out of RefAdj must be around 80uA it must be almost guaranteed. This 80uA must be an artefact of the op-amp's input circuitry whatever is inside the LM3914 and assuming I have got the circuit right.
Am I right?
But here goes. There is a fixed voltage drop between RefOut and RefAdj of 1.25V. In addition there is a 80uA (nominal) current through RefAdj to ground.
The closest I could emulate it is shown here but it is not correct. The current flowing out of RefAdj must be around 80uA it must be almost guaranteed. This 80uA must be an artefact of the op-amp's input circuitry whatever is inside the LM3914 and assuming I have got the circuit right.
Am I right?
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