Abstract: The current regulation system, providing fine dimming control, has an under-voltage circuit, an over-temperature control circuit, and sometimes a variable resistor (VR) control circuit. The under-voltage and over-temperature controls (first and second control signals) pass through voltage limiters such that the lowest level voltage control signal is applied to the voltage reference signal IREF input of LED IC driver. IC driver has a voltage reference input IREF which controls an IC output current for an LED load demand. The VR control generates a third control signal at the junction to reduce the voltage reference signal under control of the VR. The lowest level control signal dims the LED lamps. Since low level voltage control signals are used, a low voltage turn OFF circuit applies an IC disablement signal to the LED IC driver input control based upon sensing a very low voltage at the junction.

Abstract: The current regulation system, providing fine dimming control, has an under-voltage circuit, an over-temperature control circuit, and sometimes a variable resistor (VR) control circuit. The under-voltage and over-temperature controls (first and second control signals) pass through voltage limiters such that the lowest level voltage control signal is applied to the voltage reference signal IREF input of LED IC driver. IC driver has a voltage reference input IREF which controls an IC output current for an load demand. The VR control generates a third control signal at the junction to reduce the voltage reference signal under control of the VR. The lowest level control signal dims the LED lamps. Since low level voltage control signals are used, a low voltage turn OFF circuit applies an IC disablement signal to the LED IC driver input control based upon sensing a. very low voltage at the junction.