Voltage, Current, Resistance, and Ohm’s Law – There’ll be quite a bit of talk about current and resistance, so make sure you understand how they’re related with voltage. On this page, we’ll dissect the USB charger, examining all of the inputs, outputs, and specifications of the board. The charge current controls how fast your battery will charge. If you have a 1000mAh battery, charging at 1000mA will fully charge that battery in 1 hour. Есть предохранитель на 2 А для предупреждения перегрузки по току — это защита порта microUSB. Резистор программирования (R2) определяет максимальный ток заряда. Solution B (Schematic) (BoM) Features BQ24073 Power-Path enabled battery charge controller, over-discharge protection and LM3668 3.3V buck/boost power supply. Before adding the resistor, disconnect both jumpers discussed in the section above.
More information about each charging phase can be found in the app note above. Make sure you get the polarity right, though. The higher-voltage supply will source power to the chip.
There are already two resistors on-board, which can set the charge current to either 500mA and 100mA. A small jumper is used to select between those. Care needs to be taken with all parts of the design, from battery charging, to over-discharge protection, to the overall power story of the device. System Output The LiPo USB Charger is designed to be easily embeddable inside a project. Benefits include thousands of recharges and no occurrence of the “memory effect” that infested early NiCd rechargeable cells. Description: The PowerCell board is a single cell LiPo boost converter (to 3.3V and 5V) and micro-USB charger in one. The board incorporates a charging circuit, status LED, connector for your battery (JST-type used in the batteries we carry), and a micro-USB connector. A small mounting hole allows this charger to be easily embedded into a project.