Image sensor with reduced column fixed pattern noise

An image sensor may include an array of image pixels arranged in rows and columns. Each column of pixels may be coupled to current source transistors and a threshold voltage mitigation circuit. The threshold voltage mitigation circuit may include a long p-channel device for producing a reference current for the current source transistors. The mitigation circuit also includes an autozero transistor and a sampling transistor for passing a global control voltage to the current source transistors. The global control voltage may be generated using a control voltage generator that includes current mirroring circuits and a replica of the current source transistors and the threshold voltage mitigation circuit.