AUTOMATIC MODE-SWITCHING FULL VOLTAGE SEGMENTED LINEAR CONSTANT CURRENT LED DRIVE CIRCUIT

摘要

Disclosed is an automatic mode-switching full voltage segmented linear constant current LED drive circuit, comprising at least two LED groups sequentially connected in series, and a voltage detection control circuit used for detecting a power source voltage. A positive electrode end of each LED group is directly connected to a power source or connected to the power source via a switching switch. A negative electrode end of each LED group is respectively grounded via a corresponding control switch. An LED group comprises at least two LED units sequentially connected in series, and a negative electrode end of each LED unit is grounded via a corresponding control switch. The switching switch and the control switches are accessed and controlled by the voltage detection control circuit in order to alter series/parallel connection modes between the groups and turn different LED units on/off. The drive circuit switches the LED series/parallel connection modes according to the voltage, and also adjusts the total load current in a convenient and timely manner according to the wave of the voltage, thereby reducing harmonic distortion and taking the power factor into account.