Cheap charger is damage, cell phone power management need to be cautious A
The market has been sold for several dollars cheaper charger, and some cottage charger configured only cost a few dollars. These low-quality cell phone charger to ensure it? Safe? How do they save the cost of it? Saying "you pay for," Although today is not entirely correct, however, mobile phone charger market, it is still the truth. Here, you will be lifted some of the secrets of cheap chargers, and chargers to prevent the harm of these low-cost, mobile terminal power | regulator management program must be a preventive measure, can not cut corners to save costs, or else.
Causes of poor quality and hazardous charging device
MPS Asia Marketing Director Yuan Wenlin: complete charge management and protection should be divided into three parts: the charger end, the host side, the battery pack. The protection of their respective a chain, are indispensable.
Yuan Wenlin: Many markets sell the cheap charger may only use a simple winding transformers, there is no such over-voltage over-current protection.
Chargers are generally divided into Switch (switch type) and Linear (linear), with many markets selling cheap charger for profits, may only use a simple winding transformers, there is no over-current protection of overvoltage etc. also not taken into account such factors as power supply stability, the potential risk to bring the phone itself. Because mobile phone manufacturers can not predict whether its end customers to use only qualified charger charging the host, so many international brands in order to protect its reputation and reduce the cost of repairing the sale will charge the phone line plus a front-end chip protection .
State Ministry of Information Industry in 2007 by the introduction of handheld mobile communications standard charger, mobile phone manufacturers have specifically requested additional input over-voltage protection function of the host side, but the market many companies to cut costs in shipping in volume after shipment application on the network canceled the certificate was used by the overvoltage protection chip. At the same time, the battery pack side, cancel the NTC should Dianchi package over-temperature cold Baohudianzu the battery core temperature changes Wufajishi charge feedback Ji Guan Li chip, Zhe gave end users were in charge when the charge Xian Lu Dai Lai light damage , shortened battery life; serious cases such as the battery explosion / fire and other potential hazards.
Texas Instruments | Instruments high-performance analog business development manager Zhang is: from the charger side, the biggest problem is the use of optocoupler, transformer insulation is not absolutely reliable, and if to save money, poor quality of materials used, there greater safety hazards; second no-load power consumption too, and now the mainstream requirement is less than 300mW, the Japanese have begun to demand 150mW; third point is that consistency is poor, after the exchange of different adapters can not guarantee applies.
Zhang was: Some mobile phone charger management software by relying, in the event the software errors that may result in accidents and disasters.
From the host side view of a number of mobile phone charging management function from the power management chip alone PMU completed, or anyone else for the single-chip integrated baseband, which charge related work all rely on PMU or the baseband chip to implement the software. While the cost is low, but the software dependent on, if there software errors may cause unexpected disasters; on the other hand, CPU Built-in rechargeable management functions, as process constraints often can not be achieved with higher input voltage, so when the user use of poor quality, or charger, plug the charger because the surge voltage generated all possible PMU or damage to the baseband chip, this time through the software to achieve many of the protection functions are not working, may have unpredictable consequences; s Third, a number of built-charge management can only be achieved and the average pulse current charging current management, the peak current limit is to rely on the charger itself, which may cause the battery life is too short, use of public phones in the future exchange of appropriate different adapter also will be hidden after.
Saint-state microelectronics product line manager, Lu Liang: charger as the product of accessories, competition, cost too much pressure, there will be more hidden than the host side. There are usually indicators of performance and product description does not match, or the electric strength failed. Dielectric strength is the charger product safety assessment of important indicators. If consumers choose such a product, electric shock may occur, threatening the personal safety of consumers.
Security measures
PI, senior vice president Doug Bailey: There are three safety hazards battery charger, or electric shock, fire and damage to the environment.
Doug Bailey: the existence battery charger electric shock, fire and safety hazards and environmental damage.
Security design approach is to supply the high side and low side to maintain the appropriate insulation and between the gap. International Electrotechnical Commission (IEC) of the rules covering the safety of power supply design, there are many security agencies in monitoring production standards.
High quality products include thermal shutdown function, disconnect the power when the charger overheating; also has over-current shutdown feature, you can short-circuit the battery (which may lead to heat and fire) will power down to about 1% of rated power. Through the use of efficient control algorithms, and to ensure that products are free of halogen and PVC to minimize harm to the environment. These algorithms ensure that the charger in the power consumption of non-minimum state of charge.
Texas Instruments high-performance analog business development manager Zhang is: a new generation of mobile charge management chip requires the following characteristics:
Higher pressure, typically 18V ~ 26V; path management function, independent of charge and system power path path; thermal management capabilities, once the chip core temperature rises to a certain point automatically reduces charge current to ensure the safety of the system; LDO function, when the battery is not installed can boot the system, which is especially suitable for debugging or production test, certain occasions such as wireless public telephone, the battery may not be standard when it comes to cost.
USB charging power needed to meet the USB IF standard, low-power power supply 100mA, high-power power supply 500mA; Furthermore, a switch-mode charge will maximize the use of USB port 2.5W maximum power consumption.
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