Battery Power - September/October 2011 - (Page 24)

New Products • IC’s & Semiconductors The small strips of solar cells seen in the front panels of today’s small portable consumer, healthcare and security devices are set to become a more valuable source of free energy with help from a new advanced battery charging IC from STMicroelectronics. The IC will increase charging efficiency either indoor or outdoor, using the sun’s radiated energy, enabling longer mobile equipment runtime and avoiding an unexpected lack of power when a mains connection is not available. ST’s SPV1040 is a step-up DC-DC converter tailored to be used as solar battery charger for portable applications to employ Maximum Power Point Tracking (MPPT), a technique for collecting the maximum possible energy from solar cells. It can be connected to strips of even just a few cells, allowing use in products such as portable healthcare devices, watches, calculators, wireless headsets, toys or mobile phones. The battery charger and MPPT technology can also be used in equipment such as sensors and security cameras. The MPPT algorithm embedded in the SPV1040 dynamically adjusts the charger’s input impedance to ensure perfect matching with the solar cell, thereby maximizing energy transfer to the battery and improving overall system efficiency. Without MPPT, changes in the solar cells caused by temperature, ageing, dirt or unit-to-unit variation can produce mismatches that reduce the energy harvested. Available in the TSSOP8 plastic package, the SPV1040 is in full production, priced at approximately $2.00 in quantities of 1,000 units. Alternative pricing options are available for larger quantity orders. STMicroelectronics Tackles Battery-Charging Burden With Solar Charger Linear Technology Corp. has introduced the LTC3226, an inductorless supercapacitor charger with backup PowerPath controller for Li-Ion or other low-voltage system rails in applications that require short term backup power. The device employs a low-noise dual mode charge-pump architecture with constant input current to charge two supercapacitors in series from a 2.5 V to 5.5 V input supply to a programmable capacitor charge voltage between 2.5 V and 5.3 V. Charge current is resistor-programmable up to 150 mA. The device’s automatic cell balancing and voltage clamping features maintain equal voltages on both cells without requiring balancing resistors. This protects each supercapacitor from overvoltage damage that could otherwise be caused by mismatches in cell capacitance or leakage, while minimizing current drain on the capacitors. The LTC3226 has two modes of operation: normal and backup. Operating mode is determined by a programmable power fail (PFI) comparator. In normal mode (PFI high), power flows from VIN to VOUT through a low loss external FET ideal diode, and the charge pump stays on to top off the supercapacitor stack. In backup mode (PFI low), the charge pump is turned off and the internal LDO is turned on to supply the VOUT load current from the stored supercapacitor charge while the external ideal diode prevents reverse current flow into VIN. Up to 2 A of backup current may be provided from the supercapacitor through the internal LDO. The LTC3226 operates with a 55 µA quiescent current when the output voltage is in regulation. The basic charging circuit requires few external components and takes up little space; the IC is offered in a 3 mm by 3 mm QFN package. The device’s high 900 kHz operating frequency reduces the size of external components. Internal current limit and thermal shutdown circuitry allow the device to survive a continuous short-circuit from the PROG, VOUT or CPO pins to ground. Other features include CAP PGOOD and VIN PFO\ (power fail) outputs as well as a VOUT RST\ output for system housekeeping. Housed in a 16-lead, low-profile (0.75 mm) 3 mm by 3 mm QFN package, the LTC3226 operates from -40°C to 125°C. Pricing for the E and I grade devices starts at $2.67 and $3.07 each, respectively, in 1,000-piece quantities. 150 mA Supercapacitor Charger with PowerPath Control and Auto Cell Balancing Single-Chip Battery Management Device for Power Tools and e-Bike Applications Texas Instruments, Inc. (TI) has introduced a fully integrated battery protection and cell-balancing solution for Li-Ion and lithium iron phosphate battery packs. The bq77910 battery management and protection device can manage four- to 10-cell battery packs, and two devices can be stacked to protect 11- to 20-cell packs. The device simplifies battery pack designs for e-bikes, e-scooters, portable gardening tools, power tools and uninterruptible power supplies (UPS) and can also be used when replacing lead acid batteries. The bq77910 protects the battery pack by monitoring individual cell voltages and drives two N-channel power MOSFETs to interrupt current flow during fault conditions. Fault detection and recovery criteria for the device are fully programmable in non-volatile memory to suit all types of lithium battery systems. The bq77910 is available now in a 38-pin TSSOP package, priced at $2.70 in quantities of 1,000. 24 Battery Power • September/October www.BatteryPowerOnline.com http://www.BatteryPowerOnline.com

Table of Contents for the Digital Edition of Battery Power - September/October 2011

Battery Power - September/October 2011
Contents
Portable Battery Market to Reach $30.5 Billion Worldwide by 2015, Forecasts Pike Research
Panasonic Introduces High Rate Li-Ion Cell
A Comprehensive Management Approach to Maximizing UPS Availability
The Evolution of Battery Monitoring: Impedance, Resistance, Conductance or Ohmic Value
The World of Alkaline Batteries
Nickel Zinc’s Powerful Future in Stationary Storage
Batteries
Components
ICs and Semiconductors
Charging & Testing
Power Supplies
Industry News
Marketplace
Calendar of Events
Research & Development

Battery Power - September/October 2011