Maxim Integrated introduced two new single-cell battery management ICs that defend against abnormal voltages, currents and temperatures during charging and discharging that can deal damage to the batteries in phones, wearables and other compact gadgets. The Silicon Valley company said the fuel gauge ICs are for customers trying to wring more power out of a capacity-constrained lithium-ion battery without damaging it.
The chips are used to determine the voltage, current and temperature of the battery cell to help defend against over- and under-voltage, over- and under-charge and over-current conditions and short circuits, high heat or intense cold that can damage the battery or degrade its overall capacity. By measuring the battery's state-of-charge (SOC) and state-of-health (SOH), the ICs can figure out how much longer a battery can supply power under safe operating conditions.
The chips, MAX17301 and MAX17311, stand out from other battery protector ICs because they can be programmed to shut down the system at a range of currents and voltages depending on the battery’s temperature.. That not only helps protect the system from crashing due to false alarms but also makes the system more sensitive to unsafe conditions for charging and discharging, Maxim said. The chips sip only 24µA of standby current to help prolong the battery's run time.
"Ensuring that their batteries are reliable and safe is one of the foremost considerations for portable electronics system engineers," Bakul Damle, general manager of the mobile power business at Maxim Integrated, said in a statement. The importance of battery safety was underscored when Samsung was forced to halt production of its flagship phone following a series of battery fires in 2016. It recalled the Galaxy Note 7 because it had started to smoke and burst into flames.
Maxim Integrated said it slapped an additional layer of protection in the MAX17301 and MAX17311, which are both in mass production. The fuel gauges are designed to permanently disable the battery if the primary protector FET fails, overriding the secondary protector or blowing a fuse in severe fault conditions. The ICs operate from -40°C to +85°C. They can also stop themselves from being tripped in the case of short duration voltage dips due to pulse loads on the battery.
The chips cut standby current up to 80% compared to rival battery management ICs, Maxim Integrated said. The standby current can be slashed even further by disabling the protector FETs. They can also determine the battery’s remaining charge 40% more accurately than rival ICs . The enhanced accuracy helps prevent too much voltage from being pumped into or too much being drained out of the battery, prolonging its usable life, the San Diego, California-based company said.
There are other threats that Maxim Integrated is trying to defend against. Customers are also looking to protect smartphones and other gadgets from potentially unsafe counterfeit batteries, which can cause unexpected crashes or even more severe damage. The new chips defend against counterfeits and battery pack cloning by using authentication with a secret key and giving every battery a unique ID. The ICs are shipped in 3mm x 3mm TDFN or 1.7mm x 2.5mm WFN packages.
“Safety is paramount in battery-powered electronic systems and critical to their continued growth,” said Kevin Anderson, power semiconductor analyst at IHS Markit, in a statement.