Power Electronics / Power Management

Lithium battery charger with I2C control

24 November 2021 Power Electronics / Power Management

SG Micro’s SGM41509 is a battery charger and system power path management device with integrated converter and power switches for use with single-cell Li-ion or Li-polymer batteries. This highly integrated 5 A device is capable of fast charging and supports 5 V input voltage suitable for smartphones, tablets and portable systems. I2C programming makes it a very flexible powering and charger design solution.

The device includes four main power switches: an input reverse blocking FET, a high-side switching FET for buck or boost mode, a low-side switching FET for buck or boost mode switching, and a battery FET that controls the interconnection of the system and battery. The bootstrap diode for high-side gate driving is also integrated.

The internal power path has a very low impedance that reduces the charging time and maximises battery discharge efficiency. Moreover, input voltage and current regulation provides maximum charging power delivery to the battery with various types of input sources.

The device supports a low-power input voltage (5 V) source and can avoid damage from high-voltage sources with an external N-MOSFET for over-voltage protection. The device also meets the USB On-the-Go (OTG) power rating specification by supplying 5 V (adjustable from 4,5 V to 5,5 V) on the VBUS pin with a default current limit of 2,4 A (adjustable from 1,2 A to 4 A).

The system voltage is regulated slightly above the battery voltage by the power path management circuit and is kept above the programmable minimum system voltage (3,5 V by default). Therefore, system power is maintained even if the battery is completely depleted or removed.

A dynamic power management (DPM) feature is also included that automatically reduces the charge current if the input current or voltage limit is reached. If the system load continues to increase after the reduction of charge current down to zero, the power path management provides the deficit from the battery by discharging it into the system until the system power demand is fulfilled. This is called supplement mode and prevents input source overloading.

Starting and termination of a charging cycle can be accomplished without software control. The sensed battery voltage is used to decide the starting phase for charging from three phases of the charging cycle: pre-conditioning, constant current or constant voltage. When the charge current falls below a preset limit and the battery voltage is above the recharge threshold, the charger function will automatically terminate and end the charging cycle. If the voltage of a charged battery falls below the recharge threshold, the charger starts another charging cycle.

Several safety features are integrated into the SGM41509, such as over-voltage and over-current protection, charging safety timing, thermal shutdown and input under-voltage lockout. This device also features thermal regulation by which the charge current is reduced if the junction temperature exceeds 120℃ (selectable).

Charging status is reported by the STAT output and fault/status bits. A negative pulse is sent to the nINT output pin as soon as a fault occurs to notify the host. BATFET reset control is provided by the nQON pin to exit default mode or for a full system reset.

The device is available in a TQFN-4x4-24L package.


Share this article:
Share via emailShare via LinkedInPrint this page

Further reading:

Microchip expands its mSiC solutions
EBV Electrolink Power Electronics / Power Management
The highly integrated 3,3 kV XIFM plug-and-play digital gate driver is designed to work out-of-the-box with high-voltage SiC-based power modules to simplify and speed system integration.

Dual-port USB-C power delivery solution
Altron Arrow Power Electronics / Power Management
Infineon’s CYPD7272-68LQXQ is the tray packing option of the company’s dual-port USB-C power delivery solution and features an integrated dual-port USB-C PD + DC-DC controller.

Parallel redundancy power module
Conical Technologies Power Electronics / Power Management
The LIR40-40 is a wide input range DC-DC module, with a constant output of 48 V at a nominal output current of up to 40 A.

Motor protection relay front-end
NewElec Pretoria Power Electronics / Power Management
Newelec’s Motor Protection Relay front-end software isn’t just another tool, it’s a game changer that puts control firmly in your hands.

High-power three-phase supplies
Current Automation Power Electronics / Power Management
The units from Meanwell can either be supplied with a three-phase three-wire delta input of 196 to 305 V AC, or they can use a three-phase four-wire star connection of 340 to 530 V AC.

Make your small asset tracker last longer
Altron Arrow Editor's Choice Power Electronics / Power Management
This design solution reviews a typical asset tracking solution, and shows how the MAX3864x nanopower buck converter family, with its high efficiency and small size, enables longer battery life in small portables.

Local procurement should be top of mind in mine-owned solar power projects
Power Electronics / Power Management
Recent changes in government legislation have enabled businesses to develop up to 100 MW energy plants with very little red tape.

The next big shift in SA's energy infrastructure
Power Electronics / Power Management
High-voltage (HV) LiFePO4 battery energy storage systems, commonly referred to as BESS, which drastically improve the power reliability prospects for businesses, have been around for some time, but expect to see a massive surge in 2024.

Multi-channel electronic load series
Conical Technologies Power Electronics / Power Management
ITECH has recently announced the release of their upgraded IT8700P+ series multi-channel electronic loads. This new series supports master-slave parallel configuration between all the modules, allowing for different modules to be mixed and matched for synchronisation.

Self-extinguishing batteries
Power Electronics / Power Management
The most commonly used electrolyte, which is highly combustible – a medium composed of a lithium salt and an organic solvent – is replaced with materials found in a commercial fire extinguisher.