Non-isolated Quasi-Resonant Buck LED Power Switch

General Description

KP1051C is a highly integrated power switch with Quasi-Resonant Buck (QR-Buck) constant current (CC) control for LED lighting applications.

KP1051C combines a 500V power MOSFET switch with a power controller in one chip. The IC also integrates high voltage startup/IC supply circuit and a novel transformer demagnetization circuit, which eliminates transformer auxiliary winding. The IC adopts Quasi-Resonant control for high efficiency.

KP1051C integrates functions and protections of Current Limit and Leading Edge Blanking, Under Voltage Lockout (UVLO), Cycle-by-cycle Current Limiting (OCP), Thermal Foldback (OTP), LED Open/Short Protection, etc.


l   Integrated with 500V MOSFET

l   No Auxiliary Winding Needed

l   Quasi-Resonant for High Efficiency

l   Built-in Thermal Foldback

l   Built-in Charging Circuit for Fast Start-Up

l   ±4% CC Regulation

l   Very Low VDD Operation Current

l   Built-in AC Line CC Compensation

l   Build in Protections:

n  LED Short/Open Protection

n  On-Chip Thermal Fold-back (OTP)

n  Cycle-by-Cycle Current Limiting

n  Leading Edge Blanking (LEB)

n  Pin Floating Protection


l   Available with SOP-8,TO-92 and SOT23-3L Package


l   Bulb

l   Spot Light

l   Ceiling Light

l   Tube

1051C EN.png

Pin Configuration

Typical Application Circuit

Ordering Information

Part NumberDescription


SOT23-3L,Halogen free in T&R, 3000Pcs/Reel
KP1051CLPATO-92,Pb free in T&R, 2000Pcs/Box(Tape)
KP1051CSPASOP-8,Pb free in T&R, 4000Pcs/Reel