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   Emergency Lighting Module            

 Emergency Lighting Module

Safety and regulatory demands at commercial and public installation are being enforced in developing nation like ours. As a part of disaster management as in situation like natural calamity, war, fire, accidents, it is very essential to evacuate people safely outside danger zone. Many times in such critical situation, power from grid and secondary source is unlikely to be available. Emergency Lighting module provides required light from its own power source, enhancing search and rescue operations during disaster Management.

 Product Features:

Product is an Emergency lighting module consists of battery charging section and Inverter section. Major function is to provide light for visibility purpose only in during mains & DG failure. This same circuit used in emergency mode for different types of the lamps (14W, 24W, 26W, 28W, 36W, 54W) with Two hours back-up time. This circuit can be used to drive FTL as well as CFL lamps. Wattages covered are from 20W to 54W for FTL and CFL lamps. Product is provided with protection features like No load protection in charging mode, battery reverse polarity, Battery Deep discharge protection, No load protection in inverter mode.

There are two modes operation of Emergency lighting module:

a) Charging mode operation (SMPS)

In Emergency lighting module low power SMPS is used for battery charging operation. The input filter circuit attenuates the high frequency noise generated by the switching circuit. The AC voltage is rectified and then filtered. The switching and control IC TNY277 is used. IC consists of an oscillator, enable circuit (sense and logic), current limit state machine, 5.85 V regulator, bypass/multi-function pin under voltage, over voltage circuit, and Current limit selection circuitry, over- temperature protection, current limit circuit, leading edge blanking, and a 700 V power MOSFET. Tiny Switch-III incorporates additional circuitry for Line under voltage sense, auto-restart, adaptive switching cycle on-time extension, and frequency jitter. This MOSFET switches high frequency i.e. ON/OFF, control to regulate the output voltage. Feedback pin EN/UV enables input and line under voltage. Isolated step-down transformer used, converts the high frequency switching voltage to low output voltage. This voltage is rectified using high frequency rectifier diode and filter.


The generated output DC voltage is used for battery charging in constant current mode.

 b) Inverter (Discharging mode) operation

A Push-Pull circuit two MOSFET based fly back mode inverter is built to drive a lamp in emergency mode. A controller based AT tiny 45 which generates PWM is high frequency square wave (22-35 KHz) as a gate drive for a MOSFET. Generated PWM before drive to MOSFET it amplifies by using totem pole circuit then drive the MOSFET. The isolated step up transformer used, generates the high voltage required to keep the lamp ON; with battery in fully charged condition, backup time of 2 hours can be achieved. Protections like No load protection


While most of the applications used simple battery charger and inverter function, there are some premium models available in the market with self test feature and integration of emergency lighting with DALI (Digital Addressable Lighting Interface) based lighting system. However explained product is intended for middle market segment with cost effective solution.

 Salient Features:

  Implemented a solution to address following functions: 
 * 6- pole technology, 4-pole change over & a delayed action relay for switching the mains supply to ensure Compatibility with the ballast.
 * Battery Back-up time 2-Hrs; duration.
 * AC output optimized for TC-L lamps. (T5 and T8-FTL).
 * Constant battery charging when variations in the input supply 90 to 265V.
 * Change over relay with high current contacts.
 * Battery Deep discharge protection.
 * No load protection in inverter (emergency) mode.
 * Battery charging isolated from mains supply variation over wide range of input supply 90 to   265V.
 * LED indication for battery charging.
 * Double lux output (30%) compared to industry standard (15%)

  Block Diagram :


  Wiring Diagram :


Product Specification Sheet:
Model No.: BL24ELM1542 Date: 12-05-09
I. Model Description
Code Parameter Description
  Ballast Shape Linear
  Input Voltage, V 240 V
  Details Emergency lighting module
  Number of Lamps per Ballast One
  Lamp Watts, W 20-54W, Fluorescent, T5/T8
  Backup time 2 hours
  Model type Basic
II. Test Parameters – Input Characteristics
  Battery charging  
Supply Volts (Vn) 240V, 50Hz
Supply Current (In) 78mA
Power Factor (PF) 0.48
Watts (P) 9 W
Operating Voltage Range 150-265 V
III. Test Parameters – Emergency mode
Battery discharging  
Backup time Approx 2 hours on full charge
Ballast factor Depends upon which lamp to be used
IV. Protections:
Battery reverse polarity Fuse protection
Battery deep discharge Protected
No load protection Protected
Fuse protection for current limiting at input Provided
V. Physical Characteristics
Box Dimensions (LxWxH), mm 250 X 41 X 32
Ballast Mounting Holes distance mm 220
Weight in gms. 240
Maximum operating temp, tc 65˚c
Ambient temp (ta) 0-50˚c
VI. Others
Battery Ni-MH-6V, 8Ah
Battery charging voltage 7.6 V
Battery charging current 500 mA
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