【Literacy】A comprehensive analysis of LED filament lamp driving technology

I have been selling drivers for LED filament lamps  since the end of last year . During this period, new customers have many questions when choosing products. It seems that everyone is still unfamiliar with the characteristics of several driver solutions for this lamp. In order to facilitate customers to get started and to sort out the knowledge in this area, today, I would like to share with you my understanding of LED filament drivers as follows.

　　1. LED filament driver classification

　　1. From the perspective of driving solutions, LED filament power supplies are divided into three categories: RC step-down; linear constant current; IC constant current.

　　2. From the structural point of view, LED filament power supplies are divided into two categories: all-glass without plastic parts; with plastic parts. Among them, the type of lamp holder needs to be distinguished, for example, E26/E27/B22 is one category; E14/E17 is another category.

　　2. Main features of the three LED filament drive solutions

　　1. RC voltage reduction: small size, low cost, voltage change is not constant current, there is flicker, must pass EMC

　　2. Linear constant current: small size, low cost, constant current within a small voltage range, no flicker at 30cm, and must pass EMC

　　3. IC constant current: large size, high cost, good voltage change constant current accuracy, no flicker, can pass EMC

　　3. Comprehensive comparison of three LED filament drive solutions

　　4. Conventional parameters of LED filament driver

　　1. The output voltage of candle lamp 2W, 3W, 4W is 150V, and the output current is 12mA, 17mA, 24mA

　　2. The output voltage of 2W, 4W, and 6W bulbs is 150V, and the output current is 12mA, 24mA, and 36mA.

　　5. Standardization recommendations for LED filaments and filament drivers

　　Currently, the specifications of LED filaments are not unified. Some filaments are 75V, 10mA; some are 65V, 10mA; when sealing the bulb, some are 2 strings, and some are 1 string. This makes it inconvenient to order and stock filaments and drivers.

　　The characteristics of both RC and IC constant current solutions are combined.

　　It is recommended that you use 75V, 10mA filament and make 2 strings when sealing the bulb.

　　On the one hand, this method has low current, low loss, high power efficiency and high overall lighting efficiency; on the other hand, it is also convenient for standardized and inventory-based production. Especially the latter can solve the current disadvantage of filament drive, which has too many styles, cannot be stocked and has a long delivery time.