20w Pd Usb Charger For smart phones
Mobile phone chargers can be roughly divided into travel chargers, cradle chargers and maintenance chargers. Generally, users mainly contact the first two. And the most sold on the market is the travel charger.
There are also various forms of travel chargers. The common ones are the cheap duck egg-shaped miniature travel charger, the ordinary desktop card board charger, and the high-end desktop charger with crystal display. Mobile phone charger, also known as: mobile phone adapter, is actually composed of a stable power supply (mainly regulated power supply, providing stable working voltage and sufficient current) plus necessary control circuits such as constant current, voltage limiting, and time limiting. The output parameters marked on the charger (referring to the line charger): such as output 5.0V/1A, output 5.0V/1500mA-11200… refers to the relevant parameters of the internal regulated power supply. Understand this truth, you will know that a (good quality) mobile phone charger is easy to change into a good quality regulated power supply.
The chargers of lithium-ion (li-ion) batteries commonly used in mobile phones use a constant-current and voltage-limited charging system, and the charging current is generally around C2—that is, the charging rate is two hours. For example, a 500mAh battery is charged at 250mA in about two hours 4. Constant voltage charging after 2V.
The lion battery is not suitable for the -DV/DT detection fast charging method used by the NIMH battery advanced fast charger, because the lion battery has a strict limit on the charging current. Lithium ion (Li+) is very active, and high current charging is prone to danger. The general user contacts are mainly the first two. The most popular travel chargers on the market are travel chargers. There are also various forms of travel chargers. The common ones include cheap duck-egg miniature travel chargers, ordinary desktop card board chargers, and high-end desktop chargers with LCD display. device. In view of the fact that most mobile phone users are non-professional users, the chargers basically have the function of full self-stop, and most of the travel chargers are fast chargers, and the charging time is about 1-3 hours. Many chargers on the market advertise that they are controlled by microcomputers, including some very cheap duck-egg-type miniature travel chargers. In fact, strictly analyzed from the charging circuit, only a small number of chargers can be truly controlled by microcomputers (MCU control). .
Some manufacturers claim to be “microcomputer control” when they use integrated blocks on the charging circuit. In fact, many low-cost design integrated blocks are cheap op amp integrated blocks, while some dedicated charging control integrated blocks have higher unit prices. , generally used in relatively high-end or brand-name chargers. So we can’t trust the so-called microcomputer control, especially the cheap products. Many products are similar in appearance but have very different internal circuits, and their performance is also very different.