This product is very important and is an important guarantee for personal safety. The performance and technical requirements of the product are very high. For this reason, the country has formulated the specification of “fire emergency luminaire†for this product.
The production and sales of the products must pass the test of the relevant national authorities and issue the corresponding production and sales licenses before they can be produced and sold. After the products are installed, they must pass the inspection and acceptance of the fire department before they can vote. People use. Fire emergency luminaries can be divided into two types according to different power supply modes. Self-contained power supply, centralized power supply and power supply sub-type. Among them, the power supply type fire emergency luminaire is the most widely used one, especially the fire emergency evacuation lighting and signs.
Since the installation parts of such lighting fixtures are scattered and are in public places, after the fire occurs, all the electrical circuits in the site are easily burnt and burned by water. Short circuit and leakage occur after the line is wetted by water. Burning wires and short-circuit trips can stop the centralized power supply type of lamps. The sparks in the short circuit can promote and spread the fire. The leakage causes people to be exposed to electric shock. Therefore, all the lines in these places are best not charged when a fire occurs. The emergency luminaire with its own power supply works by self-contained battery in the event of fire. The external power supply line can be powered off. The quality of the external circuit will not affect the use of the luminaire. The luminaire and the luminaire do not interfere with each other. The self-contained power supply is specially designed for the emergency light of the self-contained power supply lamp. It is the best power supply method for emergency evacuation lighting and signage lamps. However, since the lamp has a battery inside, the battery pack has control of charging and discharging, external power supply and battery. The conversion of the power supply protects the open circuit, short circuit and overcurrent of the battery circuit, so that a set of control and protection circuits must be provided in the luminaire, and the reliability of the protection circuit directly affects the reliability of the emergency luminaire.
In recent years, the quality of fire emergency lighting in China is not optimistic, the product's unqualified rate is very high, and their installation parts are scattered, which brings inconvenience to maintenance management, which makes users and fire departments worry. For this reason, I believe that it is necessary to improve the quality of self-contained power supply emergency lighting. The author introduces a special emergency line to illustrate how to improve the reliability of emergency luminaires. The specific lines are shown in the figure. The public battery is connected to Xinxin. The line is composed of 2 / 0 1 chip. The emergency light source is the continuous emergency sign. It is the most used one.
To improve the reliability of fire emergency lights, the author believes that the following aspects should be improved to meet the necessary functions, to take the integrated road, simplify the circuit, and thus increase reliability.
As we all know, the more complicated the electronic circuit, the more components, the worse the reliability, and the better the reliability. The integrated circuit simplifies the peripheral circuitry, and the higher the level of integration, the simpler the peripheral circuitry. The 23 / 01 chip in the above line integrates 0 / piece of components into one, many functions have been completed by the chip, the peripheral lines do not need to use many components, the natural peripheral circuit can be simplified. The total number of components of the circuit is six, which can reduce one or six components compared with a circuit composed entirely of discrete components or general-purpose chips, so that the printing plate area is small, the number of soldering points is reduced, and the labor cost for manufacturing is reduced by %. The cost is reduced and the reliability is improved. Prolonged battery life with a reasonable and advanced charging method.
Slow down the decline in battery capacity. The decline in battery life and capacity is related to many factors. The important point is the impact of charging methods on battery life. Many experts believe that most of the current batteries are not used up, but are burnt. In the simple charging mode, there is no control link due to charging, and often due to the voltage level, temperature change, improper charging current, causing overcharge or undercharge, the battery quickly reduces the volume of the period and shortens the use time.
In order to improve the charging effect, the 23/7 chip has the following measures. The segmented charging is the best charging method for the battery. The chip adopts a five-stage charging program to control the first phase of the battery charging to detect the charging. When charging starts, the battery is judged for abnormal performance. When it is detected that the battery voltage is lower than half of the rated voltage, it may be regarded as abnormal condition such as partial short circuit or deep discharge or long-term use of battery or new battery. Using a small current charge, the battery voltage rises slowly.
If the battery is damaged, the voltage will not rise or rise to the maximum value and stop charging immediately. The second stage of normal charging is detected by the normal current constant current charging when the battery voltage reaches the rated value or the battery capacity is greater than %. The charging current is determined by the design requirements, the power supply capacity, the charging rate, the battery voltage, and the rechargeable battery. The capacity is a function relationship. When the specified value is reached, the constant current charging is ended, and the constant voltage charging is performed.
The second stage of maintenance charging detects that the battery capacity reaches above, the giant pressure charging mode replaces the constant current charging mode. This mode can automatically adjust the battery charging current according to the real-time charging state of the battery and the amount of battery charging to ensure the battery charging. The amount of electricity.
When the fourth stage trickle charge reaches the set voltage value, the main circuit charge is immediately turned off, and the other auxiliary constant current charge circuit works immediately, enters the trickle charge state, and supplements the battery pack's power with the left and right currents. The battery is always fully charged. The fifth stage of supplementary charging When the discharge amount of self-discharge is greater than the turbulent current, the voltage loses balance and falls. When it falls to the reference point + below, it enters the supplementary charging phase, and the average supplementary current is about the normal charging current. The internal zero-change standard temperature compensation measure of the chip is within the °C range, the reference voltage remains unchanged, and the precision dynamic reference function is adopted. (The hysteresis control method with memory function is adopted, and the charging is more scientific.
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