1) Capacity choice
present, double-layer capacitors is the most widely used as a memory backup power supply, because of its low power consumption (more than ten microamps to a few microamps), so double-layer the memory capacitor can be continuously carried out dozens of hours to hundreds of hours of protection. In addition, the capacitor is often used in electronic circuits in the transient voltage fluctuations in the main stable when the main power supply and
49 datasheet and support of instant power off. As the use of standby power to do so, the application must be aware of the protected circuit when some basic conditions, these conditions include the following aspects:
(1) required to maintain stable memory or the minimum line voltage Ei;
(2) required to maintain stable memory or line current,;
(3) power failure before the capacitor charge voltage E. ;
(4) memory or line stability required for the duration of the small;
(5) working temperature range. According to the above conditions, the following formula can be used to select the capacitor capacity:
C = IT / (E. - VES - Ei)
where, V ESR double layer capacitor is equivalent series resistance of the voltage generated in the storage memory protection case, because the current is very small, under normal circumstances may be considered. However, in high current applications must be considered, such as for stable high-power circuit or drive relays, solenoid valves and
49 price and micro-motors.
2) The main application of the following areas
(1) or off the main power outage during the backup power supply. In the shutdown and
49 suppliers and replacement of power, the information in RAM, the memory clock and other information needed to maintain backup power. God in this case, the double-layer capacitors to protect such information, to protect the circuit conditions and time can be double-layer capacitor capacity of a few minutes to several months. Use of the power supply circuit in the digital radio tuning system memory, recording time and keep the clock; the meter in the taxi meter system to maintain the original data; on the phone circuit, you can achieve number memory, redial and auto-response functions; In addition, the VCR, because there are micro-computer support dual-layer capacitors, so the main power outage, you can still continue to recording TV programs.
(2) the main power fluctuations or momentary power failure of instant backup power. In some electronic devices, due to the motor, relay, buzzer, or display the start and the moment caused by the voltage reduction circuit, so as to cause memory errors or circuit malfunction, the use of electric double layer capacitor voltage can play a stabilizing role. In addition, the battery-powered instruments, due to vibration and other reasons, is likely to produce instant power outage, then with aluminum electrolytic capacitors may also play a protection circuit to maintain the memory or the role. However, when the circuit current is relatively large, double-layer capacitor is the best choice. Can also be used in camera systems, taxi meter, car audio systems, automotive electronics and handheld business machines, typewriters and word processors, etc.
(3) in the solar System. In the solar-based power electronic instruments, due to frequent changes in sunlight intensity, and therefore frequent changes in voltage, electric double layer capacitor can be used as an auxiliary power supply to maintain the stability of the circuit work. At the same time. It can also be used in conjunction with solar cells as the main power low-power meter is widely used in digital multimeter and solar clocks and other fields.
(4) high-power electric double layer capacitor effect. Although the power supply type electric double layer capacitors are also far from practical level, but because of its superior performance in a variety of energy sources and systems have been showing a very bright future. According to reports, the Japanese hybrid vehicle power systems, vehicle starting system in Russia are using high-power electric double layer capacitors, and achieved satisfactory results.
3) Note
double-layer capacitors can be used in parallel or in series, but the application must ensure that the series capacitor voltage balanced distribution, so only the same specifications can be connected in series use. As the relatively large equivalent series resistance, therefore, not used for electric double layer capacitor AC circuit and filter circuit. Will open with over-voltage capacitor failure, therefore, the application of electric double layer capacitor voltage can not exceed its rated voltage.