What are CV, CC, and CV+CC which are often mentioned in LED power supply specification?

CV (Constant Voltage):Conventional power supply will provide stable regulated voltage (constant voltage) for load usage. Regardless of AC input variation (90~264VAC) or load variation, output voltage will be regulated to within voltage tolerance specification (single output unit typically 1~2%). For example, LPV-60-48 used in powering LED driver + LED light strip, output voltage will remain constant at 48V (as shown in figure 2a).
CC (Constant Current): Designed to provide stable output current (constant current), output voltage will be determined by LED total Vf. For example, using LED with Vf = 3.5V @ 350mA and with 12pcs connected in series. The total Vf will be 3.5Vx12=42V. With 2 strips connected in parallel, the total If = 350mAx2 = 700mA。 If MW constant current LED power supply LPC-35-700 (Vin = 90~264VAC, Vout = 48V/700mA) is used to drive LED load directly, LED power supply will work in CC mode. Output voltage will drop to 42VDC while output current remains constant at 700mA (as shown in figure 2b).
CV+CC MW constant current LED power supply possesses both “C.V.+ C.C.” characteristics. During startup it will operate in “C.V. mode”, which is suitable for LED driver IC and series resistor applications. Once output current requirement exceeds rated current of the power supply and reaches the constant current region, the unit will remain in the constant current mode which is suitable for direct drive of LEDs. C.V.+ C.C. characteristics can be used in all types of LED setup making system design more flexible.
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