ISL9214A

Li-ion/Li-Polymer Battery Charger Accepting Two Power Sources

OVERVIEW

The ISL9214A is a fully integrated low-cost single-cell Li-ion or Li-polymer battery charger. The charger accepts two power inputs, normally one from a USB (Universal Serial Bus) port and the other from a desktop cradle. The ISL9214A is an ideal charger for smart handheld devices that need to communicate with a personal computer via USB.

The ISL9214A features 28V maximum voltages for both the cradle and the USB inputs. Due to the 28V rated inputs, low-cost, large output tolerance adapters can be used safely. When both inputs are powered, the cradle input is used to charge the battery. The charge current is programmable for the cradle input with a small resistor. The end-of-charge current is also programmable by another external resistor. The charger incorporates Thermaguard™ which protects the IC against over-temperature. If the die temperature rises above a typical value of +125°C, a thermal foldback function reduces the charge current automatically to prevent further temperature rise. The charger has two indication pins. The PPR (power present) pin outputs an open-drain logic LOW when either the cradle or the USB input power is attached. The CHG (charge) pin is also an open-drain output that indicates a logic LOW when the charge current is above a minimum current level. When the charge current is below the preset minimum current, the CHG pin will indicate a logic HIGH signal. This status is latched and will be reset under one of the following events:

1. The part is disabled and re-enabled
2. The selected input source has been removed and reapplied
3. The USBON turns LOW
4. The BAT pin voltage falls below the recharge threshold (~3.9V)

KEY FEATURES

  • Complete Charger for Single-Cell Li-ion/Polymer Batteries
  • Dual Input Power Sources for Cradle and USB
  • Low Component Count
  • Integrated Pass Elements
  • Fixed 380mA USB Charge Current
  • Programmable Cradle Charge Current
  • Charge Current Thermaguard™ for Thermal Protection
  • 28V Maximum Voltages for Cradle and USB Inputs
  • Adapter Presence and Charge Indications
  • Less than 0.5µA Leakage Current Off the Battery When No Input Power Attached
  • Programmable End-of-Charge Current
  • Ambient Temperature Range: -40°C to +85°C
  • No External Blocking Diode Required

BLOCK DIAGRAM

 Block Diagram

PARAMETRICS

Parameters
ISL9214A
Basic Information
Production Status
Mass Production
Output Voltage Typ (V)
4.2
Voltage Accuracy (%)
1
VIN1 (max) (V)
28
VIN2 (max)
7
Output Current 1 Max (A)
1
Safety Timer
No
Self Termination
No
Accepts CC Adapter
No
VIN1 Trickle Charge (min) (% CC)
16
VIN2 Trickle Charge (min) (% CC)
17
Thermal Regulation
Yes
Function (s)
Enable, Charge Status, Programmable IMIN, Reference Voltage
Battery Chemistry
Single Cell Li+/Polymer
Qualification Level
Standard
Can Sample
YES
Temperature Range
-40 to +85

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