News & Events
Intersil Launches Advanced Li Battery Charger for Handhelds
-- Highly integrated, thermally controlled and programmable in a very small 5 X 5 mm QFN package
MILPITAS, CA, January 21, 2003 Intersil Corporation (NASDAQ: ISIL), a world leader in the design and manufacture of high performance analog and wireless networking solutions, today announced the new Endura ISL6291 Li-ion/Li-polymer linear battery charger IC. The ISL6291 charger, available in the 16-pad 5 X 5 mm Quad Flat No-lead (QFN) package, reduces parts count, saves board space and costs while offering programmability and ease of design. Target applications include cell phones, PDAs, other handheld devices, stand-alone chargers and USB bus-powered chargers.
The ISL6291 provides a low-cost, highly integrated, charger solution that eliminates the need for an external pass element, current sensing resistor or reverse blocking diode. Programmable charge and end-of-charge currents provide for efficient charging while timer and advanced temperature safety features protect both the circuit and the cell.
The ISL6291 represents the convergence of the best available technology and market research. The result is a battery charger solution that includes all of the features required for new handheld device applications, all wrapped into a space and thermally efficient package, said Dean Henderson, director of marketing for Intersils Portable Power Products. The ISL6291 relieves designers typical problems of space, efficiency, costs and thermal constraints. It also further demonstrates our commitment to enhancing the freedom of mobility through highly efficient power solutions for portable appliances.
The ISL6291 is a constant-current (CC)/constant-voltage (CV) charger. The constant charge current is programmable up to 2.0 A with an external resistor. An internal and trimmed current-sense circuit guarantees 10% accuracy with no bulky external current-sense resistor. The constant voltage is either 4.1 V (ISL6291-1CR) or 4.2 V (ISL6291-2CR) with 1% accuracy. The charger always preconditions the battery with 1/10 of the programmed charge current at the beginning of a charge cycle until it verifies that the battery can be fast-charged.
A thermal-foldback feature of the ISL6291 helps ensure safe operation, reduces design complexity and avoids premature charge termination invoked by the thermal shutdown feature of older-generation solutions. The ISL6291 controls the charge rate in relation to its die temperature. If the operating conditions, which include environment, charge source voltage and charge rate, cause the ISL6291 die temperature to approach maximum, the internal temperature control activates which automatically reduces the charge current (folds it back) to a safe level to maintain a safe temperature. In so doing, the charge cycle can continue uninterrupted and without damage to the ISL6291. As the cell voltage increases with charge, the thermal control of the ISL6291 permits charge current to increase to shorten the charge cycle.
A safety timer adds additional protection by terminating charge if the built-in control does not automatically stop charging because the programmed minimum charge current cannot be reached (such as in the case of a damaged cell or poor cell contact). The charge cycle terminates as the charge current falls below the programmed minimum current during the constant-voltage mode. The charger automatically recharges the battery when the battery voltage drops below a recharge threshold. A simple interface with an NTC thermistor avoids charging the battery outside a programmable temperature window.
ISL6291 Technical Summary
- VIN range of 4.3 V to 10 V, 13.5 V(max)
- Integrated linear pass element
- Integrated charge current sensor
- No external reverse blocking diode required
- 1% voltage accuracy
- Programmable current limit up to 2.0 A
- Programmable end-of-charge current
- Trickle charge an over-discharged battery
- Charge current thermal foldback control
- Simple interface for low-cost thermistor
- Low power-ON-reset voltage threshold of 4.3 V to accept USB bus power
- Ambient temperature range: -20°C to 70°C
- Thermally-enhanced 5 X 5 QFN package (èJA = 33°C/W)
Both the ISL6291-1CR (Vout = 4.1 V) and the ISL6291-2CR (Vout = 4.2 V) are available now and priced at $1.80 in thousand unit quantities. About Intersil
Intersil Corporation is a global semiconductor leader in the design and manufacture of high performance analog and wireless networking solutions. Intersil’s product portfolios address four fast growing markets: flat panel displays, optical storage (CD and DVD recordable), power management and wireless networking. Intersil brings added customer value in providing complete silicon, software and reference design solutions to new products that enhance the computing experience for people wherever they live, work or travel. For more information about Intersil or to find out how to become a member of our winning team, visit the company's web site and career page at: www.intersil.com
Endura is a trademark of Intersil Americas Inc.
All other trademarks mentioned are the property of their respective owners.
