Fluorescent light electronic ballast provides initial high voltage for discharging the gas inside the fluorescent lamps/bulbs. Ballast converts power frequency to very high frequency that initializes gas discharge process by controlling voltage and current through the lamps.
There are different types of light ballasts which include electromagnetic, hybrid and electronics. On this page we are talking more about the electronic ballasts which mainly provide the startup voltages. After that it maintains constant current and assures that the circuit will remain stable.
As we know that normal electricity comes with frequency of 50 – 60 Hz which electronic ballast increases and supplies to the lamp at a frequency of 20,000 Hz or higher. The benefit of this is that it eliminates the stroboscopic effect of flicker which can be due to line frequency associated with fluorescent lighting.
Principle of Electronic Ballast
Electronic ballasts are often based on the SMPS topology, first rectifying the input power and then chopping it at a high frequency. Advanced electronic ballasts may allow dimming via pulse- width modulation or via changing the frequency to a higher value.
The high output frequency of electronic ballast refreshes the phosphors in a fluorescent lamp so rapidly that there is no perceptible flicker. The flicker index is used for measuring perceptible light modulation ranges from 0-1, with 0 indicating lower possibility of flickering and 1 indicating the highest.
With the higher efficiency of the ballast itself and the higher lamp efficacy at higher frequency, electronic ballasts offer higher system efficacy for low pressure lamps like the fluorescent lamp.
Types of Electronic Ballasts
There are mainly three types of electronic ballast i.e. instant start, rapid start and programmed start.
- Instant start electronic ballasts start lamps without delay (<0.1 seconds) or flicker by providing a starting voltage that is sufficiently high in order to initiate the discharge through the lamps without waiting the need for heating lamp electrodes. For this types of ballasts the starting voltage is about 600V. Lamps associated and operated by instant start ballasts typically operate 10,000 to 15,000 switch cycles before failure.
- Rapid start electronic ballasts start lamps quickly (0.5– 1.0 seconds) without flicker by heating the lamp electrodes and simultaneously applying a starting voltage. Lamps operated by rapid start ballasts typically operate 15,000 to 20,000 switch cycles before failure.
- Programmed start electronic ballasts are best option to provide maximum lamp life in frequent lamp starting applications such as in areas where occupancy sensor controls are used. Lamps operated by programmed start ballasts typically operate up to 50,000 switch cycles before failure. Hence providing the maximum life span.
How Electronic Ballast Functions
Electronic ballast uses solid state electronic circuitry to provide the proper starting and operating electrical conditions to power discharge lamps. The ballast may be “potted” with a resin to protect the circuit boards and components from moisture and vibration.
There are different types of light ballast circuits i.e. self oscillating and IC driven circuits. Also a new Capacitor Couple Converter (CCC) circuit developed at the HKU Power Electronics Lab is becoming famous.
Electronic ballast can be smaller and lighter than a comparably-rated magnetic one. Electronic ballast is usually quieter than a magnetic one, which produces a line-frequency hum by vibration of the transformer laminations.
Main technical characteristics & Benefits are:
- Start performance is good at low pressure condition, can start smoothly, and preheat tubes after a starting point, to avoid The Times.
- Adaptive voltage range
- Preheats the startup that greatly prolongs lamp life, reduces costs, and enhances environmental protection.
- High power factor, all specifications achieved 0.98.
- Pressure, flow and output abnormal state protection function
- Eliminates strobe light, more stable. To improve vision, improve efficiency, reduce the resolution of continuous operation visual fatigue, help protect eyesight.
- Low noise, lightweight.
LED lighting is the new trend which is now leading the optical industry, which is one of the world’s most energy- intensive sectors. In addition, it has become the most important axis of “Low-carbon Green Growth” industry due to its high-energy efficiency and long life, and has been diversely expanding its application field to electricity/electronics/lighting, and so forth as the key industry of green contents that IT technology and semiconductor technology are integrated.