Conventional car chargers for car batteries (car 12V, truck 24V) are widely used in the field of lithium battery charging for various portable handheld devices, such as mobile phones, PDA, GPS, etc. Vehicle charger should not only consider the actual demand of lithium battery charging (constant voltage CV, constant current CC, overvoltage protection OVP), but also consider the harsh environment of vehicle battery (transient peak voltage, system switching noise interference, EMI, etc.). ); Therefore, the power management IC selected in the vehicle charging scheme must meet the following requirements at the same time: switching power supply chip with high voltage resistance, high efficiency, high reliability and low frequency (conducive to EMI design); Generally speaking, it is "honesty".
principle of operation
Common car charging schemes are briefly described as follows:
[1] Schematic diagram of low-end car charging scheme realized by single chip microcomputer 34063A
Advantages:
Low cost;
Disadvantages of car charger:
(1) has poor reliability and single function; No safety measures such as over-temperature protection and short-circuit protection;
(2) Although the output is DC voltage, the way to control the output constant current charging current is the maximum switching current peak limit, and the accuracy is not high enough;
(3) Because 34063 is 1.5A switching current PWM+PFM mode (there is no error amplifier inside).
The DC voltage and current ripple output by the on-board charging scheme is relatively large and not pure enough; The output current capability is also very good.
Limit; (common in low-end car charging schemes between 300 ma and 600 ma)
[2] Schematic diagram of vehicle charging scheme with 34063+NPN (NMOS) for current expansion.
Advantages: Based on the [1] scheme, the current is expanded to meet the increasing demand for charging current capacity.
Disadvantages: [1] The scheme has similar disadvantages.
[3] Schematic diagram of using 2576+358+ voltage regulator.
Advantages: (1) Because 2576 has built-in safety measures such as over-current protection and over-temperature protection, it is combined with 358 (double operational amplifier) to realize the functions of outputting constant voltage CV, constant current CC and over-voltage protection OVP; A reliable, safe and perfect lithium battery charging scheme is realized.
(2) Because 2576 is a fixed 52K PWM converter, the EMI design of vehicle charger is relatively easy.
(3) Because both 2576 and 358 are manufactured by 40V high-voltage bipolar process, they are more "solid".
(4) This scheme is commonly used in 0.8A ~ 1.5A car charger; Disadvantages: (1) The system is relatively complex and the cost is high.
(2) Constant current CC and overvoltage protection OVP are realized by the output of 358 controlling the EN of 2576, so the charging current ripple is relatively large, and the response speed of CC and OVP is not fast enough (realized by switching whether 2576 works or not).
[4] XLSEMI design schematic diagram of single-vehicle charging IC XL4002
Based on the system requirements in the field of vehicle charging, Shanghai Xinlong Semiconductor Co., Ltd. provides a series of single-chip IC dedicated to vehicle charging scheme; In addition to the conventional over-current protection, over-temperature protection and output short-circuit protection, CV, CC and OVP special for lithium battery charging are also built in. It is equivalent to integrating all functional modules such as 2576+358+ voltage regulator in scheme [3] into one IC.
Advantages: In addition to the corresponding advantages in [3], there are:
(1) A fully integrated scheme dedicated to vehicle charging has low system cost and high reliability.
(2) CV, CC and OVP in 2)IC are all realized by controlling PWM; Therefore, the output voltage, output current and output overvoltage protection have higher accuracy and faster response.
(3) Xinlong provides a series of cost-effective products, and the charging current is between 0A and 3A.
[5] XLSEMI series products quick selection table
Product model xl4001xl4002xl41kloc-0/xl4102.
Switching frequency150khz 52khz150khz 52khz.
Output current 2A 2A 3A 3A
Packaging sop8-epsopu8-epto263-5l to263-
Vehicle charger application
Car charger is an accessory for the convenience of car owners to charge digital products anytime and anywhere with car charging power supply. Some high-end car chargers generally have two USB ports, which can charge two digital products at the same time. These products generally have overload protection, short-circuit protection, high-voltage input protection, high-temperature protection and four-fold safety protection functions to ensure safe use. The car charger can be used at home or in the car, realizing the multifunctional purpose of car charging, direct charging and USB charging.
Features: Multifunctional, portable, fashionable and safe.
With the development of automobile industry, the application of car charger is more and more extensive, showing the characteristics of multi-function, portability and fashion. In the market, the more influential car chargers include rice universal charging and other products. This product's unique power management scheme, output current 1A, is the fastest charging USB charger in the world.
Multifunctional: this car charger is equipped with four AC connectors: American standard, British standard, Austrian standard and European standard; It integrates vehicle charging, direct charging and USB charging to meet the charging requirements under different conditions. Dual USB output interfaces can charge multiple electronic products. Moreover, this product is also the world's first charger for charging the iPad, which can be completed in about 4 hours, and you can also take the iPad for a ride. Portability of car charger: portability is a major trend in the development of electronic products today. The universal rice charger adopts a unique folding car charger design, which concentrates the product volume to 6.9×5.6×3. 1cm, making it extremely convenient to carry around.
Fashion: For car owners, a high-end consumer group, the fashion of car chargers is also valued by manufacturers. Generally, ABS material is used, and the piano painting process is not only fashionable and exquisite, but also has a very good feel.
Safety: This product has passed the international safety performance tests such as CCC, UL, FCC and ce. And guaranteed by the insurance company, which effectively guarantees the safety of performance and the rights and interests of consumers.
Function introduction
Folding GPS positioning
A GPS company in Shenzhen has developed and produced a car charger with GPS positioning function, which can realize real-time tracking, historical trajectory playback, parking spot inquiry, collision alarm, overspeed alarm, geographical fence alarm and other functions. It has a monitoring platform, which can be accessed through mobile phones and computers, and provides mobile APP download for easy positioning. For young people who like to play Weibo and road trip, a "Share" button is added to their mobile phones, and they can choose driving tracks for a period of time.
Folding USB interface
The car charger can charge the mobile phone not only through the car adapter and cigarette lighter, but also through the USB interface of the computer.
◆ Product name: Oshur ozio car phone charger /5-in 1 USB car charger /MP4 fast charging B2 1
◆ Manufacturer model: B-2 1
◆ Weight: about 120g
◆ Accessories: 5 universal adapters (2 Nokia 1 Motorola 1 Samsung 1 Sony Ericsson)+1 cigarette plug charger+1 USB data cable.
◆ Product features:
1.500 mA fast charge. There are two ways to charge mobile phones: car 12V or 24V power supply and computer USB interface.
This product supports the charging of mobile phones and MP3 and MP4 with USB interface, which can be charged directly in the car or through a computer. The maximum current of this product is 500 mA, which can quickly charge the mobile phone, making it the best choice in case of emergency.
(1) The mobile phone can be charged from the USB interface of the computer with the adapter.
(2) The mobile phone can be charged through USB car charger adapter (including cigarette lighter); (3) You can charge any MP3\MP4 that supports USB charging.
2. Patent number design: color charging instructions, super convenient to use.
3.5 Different mobile phone interfaces are suitable for various mobile phone models including Nokia, Motorola, Samsung and Sony Ericsson, as well as mobile phones supporting USB charging.
◆ Technical parameters:
Input: DC 12V-24V (with built-in fuse 2A)
Output: 5-6V/DC 500mA (maximum)
Product certification: CE and FCC certification.
◆ Usage:
1. Insert the USB power adapter into the cigarette lighter in the car and charge it when the indicator light is on.
2. Connect the mobile phone, MP3 or standard USB interface product with the vehicle USB power adapter by using USB cable and adapter to charge it.
Product characteristics
Features:
1. Computer automatic protection chip, which can be used safely anywhere and provide perfect protection for your equipment when charging.
2. Car charging plug structure, built-in fuse, over-voltage current is too large, the fuse automatically melts, protecting the safety of the machine.
3. The car charger also has a USB interface, which supports various USB interface power outputs.
4.IPhone/ipad can be charged through the power output interface.
Matters needing attention
The car charger uses the car cigarette lighter as a power socket to directly charge the mobile phone. Because the voltage provided by the car is low, there is only one overload protection circuit in the car charger. The front end of the vehicle charger socket is designed with a safety tube. When the current exceeds the allowable range of the overload protection circuit, the fuse will be blown immediately for protection. Note: You can only charge the car when the engine is started! Regarding the car charger, there are the following precautions:
1, don't use the car charger in wet environment.
2. Do not store the car charger in a humid environment.
3. The suitable temperature is 0-45℃
Step 4 stay away from children
Step 5 avoid lightning strikes
6. Unplug the plug in time after charging.
Therefore, for safety reasons, you must buy regular brands and genuine inferior products, which is prone to security risks. Car chargers are also divided into direct charging and seat charging. You can choose to buy a charger, that is, remove the battery to charge it, so as to avoid the phenomenon that the mobile phone burns out because of the unstable power supply and the sudden peak of high-voltage output. If you want to burn it, you will also burn the battery to reduce the loss. There are many kinds of car chargers to choose from in the market. If you choose online shopping, you must go to a regular website to buy it. The better websites are JD.COM Mall, Dangdang.com and Qiqi.com, of which the first two are large-scale comprehensive malls, and Qiqi.com is the largest and most professional online auto supplies mall at present, which is authentic and can be used as a reference for riders.
product usage
Car charger is an accessory for charging digital products anytime and anywhere with car power supply, which saves you battery cost. These products generally have overload protection, short circuit protection, high voltage input protection, high temperature protection and four-fold safety protection functions to ensure your safe use.