Design of new LED emergency light control circuit
The emergency light is mainly used for providing emergency lighting after the normal lighting power supply is cut off or the power grid is out of power. It is often used in factories, mines, institutions, schools, buildings and tunnels. The emergency lighting system used in China is mainly controlled by its own power supply. The normal power supply is connected to the normal lighting power supply circuit. The emergency light battery is charged normally. When the normal power is cut off, the backup power supply (battery) is automatically powered. This type of emergency light has a large number of electronic components such as transformer, voltage regulator, charging, inverter, battery, etc. inside the lamp. The battery needs to be charged and discharged during use, maintenance and failure.
The other is a centralized control type of power supply. There is no independent power supply in the emergency light. When the normal lighting power supply fails, it is powered by the centralized power supply system. In this form of emergency lighting system, the complex electronic circuits inside all the lamps are omitted, and the emergency lighting fixtures are no different from ordinary lamps, and the centralized power supply system equipment is in a dedicated room.
At present, the control power supply of most LED lamps and ordinary lamps is the same in complexity, and the power of each control power source is fixed and cannot be adjusted according to actual needs. The LED emergency control circuit designed in this paper is a complete and independent system, which can be used with LED power supply of different powers, which is simple and convenient, and flexible in use.
First, the new LED emergency lighting principle and advantages and disadvantages
The block diagram of this new LED emergency lighting is as follows:
Figure 1 Block diagram of the new LED emergency lighting fixture
When the utility power is normal, the LED driving power supply supplies power to the control board, and the driving light source emits light. The mains charges the battery through the charger. When the battery is fully charged, the power is cut off by the protection circuit to stop charging. When the utility power is cut off or pulled, the battery supplies power to the emergency part of the light source, and the emergency light source is supplied to the emergency light source through the emergency control circuit.
In this design, the emergency light source may be a whole or a part of the normal illumination source; the normal illumination source and the emergency illumination source may be separated separately or as a whole. Just adjust the peripheral circuit slightly.
The emergency control circuit is a relatively new and unique place in this design. It is mainly composed of MT7201 chip, peripheral circuit and relay. The external detection part can be designed into various forms such as microwave radar detection emergency illumination, infrared detection emergency illumination, sound control, and light control.
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