Switching power supply controller for constant current driving of LED by primary side control and method for constant current driving of LED

Abstract

The invention discloses a switching power supply controller for constant current driving of an LED by primary side control, a method for the constant current driving of the LED and a switching power supply control device formed by using the switching power supply controller. The switching power supply controller consists of an input dimming angle detection circuit, a multiplier, an on-signal control circuit, a zero-crossing detection circuit, a comparer, a trigger and a driving circuit. A circuit controls the constant current driving of the LED by using a primary side control method to realize same output current and high power factor under the condition with controlled silicon dimming and high-low voltage input; and transformer isolation is directly used, so that the safety performance of the circuit is improved, a peripheral circuit is simple, the circuit cost is reduced, and the PCB (printed circuit board) distribution space is very small in favor of product miniaturization.

Description

technical field [0001] The invention relates to LED lighting technology, in particular to power factor adjustment (PFC), thyristor dimming, primary side control LED constant current driving technology. Background technique [0002] As LED technology develops, the brightness and efficiency of LEDs continue to increase. LED lighting for daily households continues to develop, and has gradually become the mainstream of energy saving, emission reduction, and green lighting. [0003] The traditional AC power supply LED constant current drive circuit with power factor adjustment (PFC) function has two structures: isolated type and non-isolated type. There are two control structures in the isolation structure, one is two-level control, and the other is single-level control. Compared with two-stage control, the circuit of single-stage control is relatively simple, and the cost is relatively low. [0004] In the isolated single-stage control LED drive circuit, the optocoupler feedb...

AI Technical Summary

Problems solved by technology

[0004] In the isolated single-stage control LED drive circuit, the optocoupler feedback is generally used to obtain the constant current control signal. Due to the optocoupler feedback, an error amplifier needs to be added on the secondary side to sample the output current, and the optocoupler is also required to achieve isolation. The output current signal is transmitted to the input terminal, which requires more components and the circuit implementation is more complicated

The PCB layout space is very large, which is not conducive to product miniaturization, and the circuit cost is high

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