Application Note

Primary and Secondary Batteries

BatterySince batteries are important components of today's diverse array of portable equipment, protection of the battery pack is essential to keep the system up and running. Battery chargers are designed to accommodate the power specifications of specific batteries. Charging is limited to the needs of a battery's given charge at any point in time. If the charger's current limiting circuitry fails, the battery pack can be charged beyond what it is designed to handle, thus damaging an expensive battery pack.

Protection of the battery and equipment being powered while the battery is installed can be achieved by several current limiting technologies including PPTC resettable fuses. However, when the battery pack is removed from the portable equipment, it is susceptible to a short circuit across its contacts. Here, designers have fewer choices. High discharge due to short circuits can permanently damage the battery pack, and may constitute a serious potential hazard. Multifuse® Resettable Fuses in the MF-S and MF-LS form factors can prevent such accidents, and the consumer will greatly appreciate the manufacturer's attention to this detail.