This reference design showcases an Infrared LED illumination sub-system for Internet Protocol (IP) network cameras with day and night vision. The system features a cut filter control: LED dimming: ambient light measuring and ballasting for current of each IR LED string. Ballasting is an alternative for driving multi-string LED arrays with a single string LED driver while maintaining uniform illumination under low-light conditions. The OPT3001 Ambient Light Sensor (ALS) with precise visible light measuring and good IR rejection: is an ideal preferred replacement for photodiodes: photoresistors or other ambient light sensors.