Summit charger IC enables slimmer designs

Summit Microelectronics has expanded its range of programmable battery charger integrated circuits (IC) for single-cell Li-ion and Li-polymer powered systems.

The SMB239 is a small charger IC that enables slimmer industrial designs for portable consumer electronics.

The device's battery charging parameters are programmable via the I2C interface and non-volatile memory, allowing system design without any hardware changes.

A set of safety features is incorporated, offering system reliability and protection and eliminating the need for external safety components.

The SMB239 comprises an integrated 500mA linear charging solution that utilises a programmable algorithm for single-cell Li-ion and Li-polymer cells.

All charging parameters - pre-charge/fast-charge/charge termination current, cell float/pre-charge voltage, battery temperature/timer safety limits - are configurable via the IC/SMBus interface, enabling a wide variety of algorithms without hardware changes.

Default (custom) configuration in non-volatile memory allows the same product to be used in different system designs and/or with different battery types and technologies, resulting in lower qualification/inventory costs and sourcing risks.

Host/software control capability allows in-system adjustment of the charging profile, minimising charging time and enhancing safety.

The SMB239 is offered in a 2.1mm x 1.3mm CSP package and requires just two small external chip capacitors for a complete battery charging system design.

Unlike other linear chargers offered in packages with a limited number of pins - most of which need to be used for hardware-based programming - the SMB239's chip-scale package allows the integration of a higher number of features, including critical charging protection functionality.

The device eliminates the need for multiple external components necessary for setting charging parameters, thereby reducing system cost and size.

The SMB239 integrates a complete set of features to meet strict safety standards, including IEEE1725.

These include input and battery over-voltage protection and blocking (+10V), current limit, chip and battery thermal protection, safety timers, battery missing detection and a variety of status and fault registers.

A Status output pin is also available for indicating charge status and fault conditions.

The SMB239 also allows the system to initiate battery charging only when battery voltage is below a certain threshold, thereby eliminating frequent charge cycles that may affect battery life.

The SMB239 is suitable for a wide range of portable devices, including Bluetooth mono/stereo headsets and other accessories, mobile phones, digital cameras, portable music players, portable GPS navigation, and hand-held medical equipment.

The features, size and integration of the SMB239 make it especially suited to devices that include a USB interface because it allows a tiny industry-standard micro USB connector to be the primary data and power/charging interface.

The SMB239 operates with an input range from +4.35V to +6.5V input and safely withstands continuous input over voltage up to +10V (non-operating), while protecting downstream circuitry.

Ensuring long battery life when not connected to a DC power source, the device's reverse leakage current is less than 2uA.

The SMB239 is offered in a 2.1mm x 1.3mm, eight-ball, lead-free chip-scale (CSP) package (0.5mm ball pitch) with an operating temperature range of -30C to +85C.

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