Lithium ion battery charger implementation using C8051F300 app note(PDF!) from Silicon Labs.
Driven by the need for untethered mobility and ease of use, many systems rely on rechargable batteries as their primary power source. The battery charging circuitry for these systems is typically implemented using a fixed-function IC to control the charging current/voltage profile.
The C8051F30x family provides a flexible alternative to fixed-function battery chargers. This application note discusses how to use the C8051F30x family in Li-Ion battery charger applications. The Li-Ion charging algorithms can be easily adapted to other battery chemistries, but an understanding of other battery chemistries is required to ensure proper charging for those chemistries.
App note: Lithium ion battery charger using C8051F300 – [Link]
The charging system for a portable device is not always given a high priority in design but it can have a major role in the battery life of the system and, properly optimized, can allow the use of a smaller battery pack than otherwise would be needed. Not only are compact battery-management controllers needed, but intelligence also needs to be deployed tactically to allow the power system to be correctly optimized. This article will look at the needs of the Li-ion chemistry in terms of charging and what techniques can be used to maximize energy delivery and storage and summarize key solutions available for that purpose.
Lithium-Ion Batteries Call for Multi-Cycle Support to Maximize Uptime – [Link]
by Einar Abell @ edn.com:
This Design Idea gives two versions of an indicator light that changes from green to red as a battery discharges. There are many circuits that do this sort of thing, but all the ones I have seen are too complex and costly for my taste. This DI shows a method that uses an absolute minimum of low cost parts: a dual-color LED and four other parts.
Voltage indicator transitions between colours – [Link]
by Colin Jeffrey @ gizmag.com:
Dendrites – thin conductive filaments that form inside lithium batteries – reduce the life of these cells and are often responsible for them catching fire. Scientists working at the Pacific Northwest National Laboratory (PNNL) of the US Department of Energy claim to have produced a new electrolyte for lithium batteries that not only completely eliminates dendrites, but also promises to increase battery efficiency and vastly improve current carrying capacity.
New electrolyte promises to rid lithium batteries of short-circuiting dendrites – [Link]
The Qduino Mini is the first tiny Arduino compatible that has a built-in battery charger & fuel gauge.
The Qduino Mini is perfect to embed in your electronics projects, it’s super small, inexpensive, has a battery connector & charger built-in, & a fuel gauge that can tell you when to charge the battery!
The Qduino Mini is Arduino-compatible & 100% open source, hardware and software meaning that making and programming your first circuit is a breeze. Hardware is hard, so we decided to make it a little bit easier. The day that the first Qduino Mini ships, all of the design files, including EAGLE board files, schematic, and code will be released under an open source license. Here’s what it includes:
Qduino Mini: Arduino Compatible + Battery Charger & Monitor – [Link]
by T.K. Hareendran:
Here is a tried and tested sample circuit of a Li-Ion battery charger that can be used to charge any 3.7V Li-Ion battery using a 5VDC (USB, Solar Panel…) power supply. At the heart of the circuit is one microchip MCP73831, available in SOT-23-5 package. MCP73831 is a highly advanced linear charge management controller for use in space-limited, cost-sensitive applications. This IC employs a constant current/constant voltage charge algorithm with selectable preconditioning and charge termination.
3.7V Li-Ion Battery Charger Circuit – [Link]
Standalone Linear Li-Ion battery charger with thermal regulation in ThinSOT application note (PDF!) from Linear:
The LTC4054 is a single cell lithium-ion battery charger using a constant-current/constant voltage algorithm. It can deliver up to 800mA of charge current (using a good thermal PCB layout) with a final float voltage accuracy of ±1%. The LTC4054 includes an internal P-channel power MOSFET and thermal regulation circuitry. No blocking diode or external current sense resistor is required; thus, the basic charger circuit requires only two external components. Furthermore, the LTC4054 is capable of operating from a USB power source.
App note: Standalone Linear Li-Ion battery charger with thermal regulation – [Link]
The bq2510x series of devices are highly integrated Li-Ion and Li-Pol linear chargers targeted at space-limited portable applications. The high input voltage range with input overvoltage protection supports low-cost unregulated adapters.
The bq2510x has a single power output that charges the battery. A system load can be placed in parallel with the battery as long as the average system load does not keep the battery from charging fully during the 10 hour safety timer.
The battery is charged in three phases: conditioning, constant current and constant voltage. In all charge phases, an internal control loop monitors the IC junction temperature and reduces the charge current if an internal temperature threshold is exceeded.
BQ25101H – 250-mA Single Cell Li-Ion Battery Charger, 1mA termination, 75nA Battery leakage – [Link]
Spacewrench over at Dorkbotpdx published a new build, a Power Playground project:
It’s a PMOS/NMOS H-Bridge with FETs that can handle 3 amps or so, plus a SPI current sensor, some switches & a rotary encoder (not stuffed yet), and a 7-segment display, all controlled by a Teensy-3.1 running FreeRTOS.
I made this because I’m always running into battery, power, inductor and transformer issues I don’t have any experience with. The idea is to use the H-bridge configuration and current sensors to experiment with moderate-current PWM, motor control, power-line synchronization, battery charging and discharging, etc.
Power playground project – [Link]
by Vladimir Rentyuk @ edn.com
Suppose that you need to test a 1.5V, AA-size alkaline battery. You can apply a short circuit and measure current, or you can measure open-circuit voltage, but neither method properly tests the battery. A suitable test current of approximately 250 mA gives you a more reasonable test. You can use a 6Ω resistive load at 1.5V, which produces an output voltage of 1.46V at an ambient temperature of 25°C if the battery is in excellent condition. A poor battery might produce less than 1.2V. Given the load, the output current at 1.2V will be 200 mA instead of 250 mA. The battery will have just 80% of a full load current. Instead, you can use the circuit in Figure 1 to produce a constant-current load.
Circuit provides constant-current load for testing batteries – [Link]