Cost-effective LED lamps favored

Optimizing the product design will make the parity LED lamps more cost-effective.

Based on the difference of the power supply grid voltage around the world, the LED lamps and lanterns divide the power voltage input into two kinds: wide voltage input and constant voltage input; in order to be able to commonly use the grid voltage in different regions, LED lamps with wide voltage input become mainstream products, wide voltage input The LED lamp power supply needs to use the power source of the switching constant current source. When the voltage of the power supply network changes from AC84-280V, it depends on the switching power supply automatic buck-boost control and outputs a constant DC current. LED lamp beads must work in a constant current environment to emit light normally and efficiently without flicker.

Switching constant current source power supply is to rely on the machine's switching frequency and transformer to automatically raise and lower the voltage, to deal with grid voltage fluctuations, output a constant DC current, provided to the LED lamp beads to make it normal light.

The grid current enters the LED drive power and is preferably treated by EMC. After the bridge rectifier, the AC is converted into DC. Secondly, the power control chip and the transformer reduce the high-voltage DC voltage to the working voltage required by the LED lamp beads, and the output is constant. The operating current; With the appropriate operating voltage, to meet the LED lamp beads VF voltage and IF constant current requirements, LED lamp beads can be normal light.

However, the grid voltage is 50Hz or 60Hz AC frequency, the voltage waveform is a sine wave, so after rectification is a pulsed DC current rich in 50Hz power frequency and frequency doubler ripple, ripple is the residual AC component, must After electrolytic capacitor filtering, energy storage, charge and discharge, can get a relatively smooth DC.

The main chip control IC for the switching constant current source needs a clean power source without ripples, and it is necessary to eliminate the ripple in its operating circuit, so it is necessary to bypass the filter capacitor. Switching constant-current power supply through the circuit in the transformer output LED drive current, the diode is simply rectified into DC, so it will contain a lot of ripple, low-frequency ripple will produce the human eye can see the flicker, you must use the electrolytic capacitor to filter the ripple net.