A current source conditioning circuit arranged in a loop with a power supply circuit and a current source circuit, and a conditioning method are disclosed. The current source conditioning circuit is configured to control the magnitude of the supply voltage output by the power supply circuit so as to maintain the voltage drop across each current source in the current source circuit within a limitedrange of voltage values. The limited range of voltage values may be defined such that each current source in the current source circuit may properly adjust the drive current provided to the respective light source coupled thereto, and such that the amount of power dissipated by each current source in the current source circuit during operation is kept within an acceptable range.