LED Strip

PFC stage circuit operates in continuous mode. Input current through R5, R8 and R13 through U1  LED Downlight pin ② testing. Output DC bus voltage (395V) by divider R7, R10, R12 and R13 samples fed to U1 pin FB.U1 pin to a voltage error amplifier output ④ , C17, C18 and C21 for the compensation network. By PFC stage current is sensed R4 and R11 and C20 by the U1 pin ③ to detect .

 U1 drive output on pin ⑨ promote VT1/VT3 and VT2.PFC boost converter is the role of the bridge rectifier BR1 and the input produces an AC input voltage tends to the same phase sinusoidal current to meet the IEC61000-3 -2 standard harmonic current limits , the system power factor is much higher than 0.95 , and in the 85 ~ 264V AC input voltage range of 395V to output a stable DC voltage.

LED Strip

( 3 ) start-up circuit and bias supply

R5, R8, R6, R9, VT4, VD4 and C16 , have also formed on the U1 pin ⑧ shoulder moving circuit , U1 , once started , PFC into the operating state , U1 L1 pin by pin ③ ③ and ④ between auxiliary winding , C1 and C2, VD1 and VD2, R15, VZ1, VT5 , and C16 composed of the bias power supply.

2.2 LLC resonant half-bridge power stage

GU10 

LLC resonant half-bridge power stage circuit shown in Figure 2 (b) in Fig. The main circuit of the power stage from Figure 2 (c) shows a control circuit to control .