No bridge, no electrolytic capacitor, low ripple isolated LED lamp constant current power supply

Abstract

The invention discloses a bridgeless, electrolytic capacitor, low ripple isolated constant current power supply for LED lamps, comprising an AC power supply circuit, a start-up and power supply circuit, a coupling output circuit and a ripple suppression circuit; the AC power supply circuit includes an AC positive half-wave current loop and AC negative half-wave current loop, the current of the above current loop flows through the primary windings N11 and N12 of the magnetic integrated transformer TR, and induces a secondary current in the middle column secondary winding N2 of the magnetic integrated transformer TR; the start-up and power supply circuit includes The start-up and power supply circuit of constant current driver chips U1 and U2; the coupling output circuit rectifies and filters the induced secondary current and outputs it to the load LED lamp; the ripple suppression circuit recovers harmonic THD and electromagnetic interference EMI, and outputs it to the load after rectification LED lights; constant current driver chips U1 and U2 use DU8673 integrated chips. The constant current power supply of the present invention does not use bridge rectification to improve electric power, does not use electrolytic capacitors to improve reliability, has high constant current precision, small current ripple, no flickering of LED lights, and is environmentally friendly.

Description

technical field [0001] The invention belongs to the constant-current power supply technology for LED lamps, in particular to a low-ripple isolated constant-current power supply for LED lamps without bridges and electrolytic capacitors. Background technique [0002] The DU series chip of Shanghai Duty Cycle Electronic Technology Co., Ltd. is a combination of mature low-cost analog technology and high-precision digital programming technology. Among them, DU8673 is a buck constant working in TRUQR quasi-resonant mode Current drive chip, built-in 600V high voltage MOSFET tube, mainly used in small and medium power LED constant current drive power system. DU8673 integrated chip is suitable for input power supply voltage range of 176Vac to 264Vac; output voltage of 40Vac to 80Vac, output constant current of 0.3A; power factor of 0.5. Even in the case of output short circuit, the constant current characteristic can still be maintained. But at present, the application of DU8673 in...

AI Technical Summary

Problems solved by technology

But at present, the application of DU8673 integrated chip mostly uses rectifier bridge and electrolytic capacitor, so the power factor is low, the reliability is not ideal, and the volume is large. Therefore, it is necessary to study the bridgeless, electrolytic capacitor and low ripple isolated LED lamp based on DU8673 integrated chip. Constant current power supply

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