SMB136

Preliminary Information

http://www.summitmicro.com/

2141 2.0 7/7/2009

1

Programmable Switching Li+ Battery Charger with USB/AC Input, CurrentPath™ Manager,

INTRODUCTION

• Automatic Input Current Limit for universal USB/AC/DC adapter

compatibility*

• Optional automatic power source detection per latest USB

charging specification 1.0

• USB input with programmable input current limiting (USB2.0

compliant)

• Up to 750mA charging output from 500mA USB port or 1500mA

from AC adapter using proprietary “TurboCharge

• Input/output CurrentPath™ control allows system operation

with deeply discharged/missing battery – no start-up delay

• “Low Battery Recovery” mode for >500mA startup from 100mA

USB port with deeply discharged cells – no start-up delay

• USB On-the-Go (OTG) power support (up to 500mA @ +5V)

• Reverse current blocking prevents battery discharge

• High-efficiency step-down regulator with 3MHz switching

• +4.35 to +6.2V input voltage range

• +18V input tolerance (non-operating)

• High-accuracy float voltage regulation: 1.0%

o

Pre-charge voltage, float voltage

o

Input/pre-charge/fast charge/term. current

o

Battery temperature limits, safety timers

• Comprehensive protection features

o

Status/fault indicator

o

Battery/IC thermal protection

o

Short circuit/UV/OV protection

o

Charge termination safety timers

o

Software watchdog timers

• Tiny CSP-30 package

Applications

The SMB136 is a programmable single-cell lithium-ion/lithium-polymer

battery charger designed for a variety of portable applications. The

device provides a simple and efficient way to charge high-capacity Li-

Ion batteries via a USB or AC power source. Unlike conventional

charging devices, the SMB136’s high-efficiency switch-mode operation

eliminates the low charge current and thermal problems of

conventional linear solutions. Also the switching architecture in

conjunction with programmability enables dramatically faster charging

– TurboCharge™ mode - from current limited in puts such as USB.

The SMB136 works seamlessly in conjunction with a USB controller.

Also the SMB136 can manage two outputs independently: battery

charging and system power. This allows immediate system operation

even under missing/deeply discharged battery conditions. In the case

of a low battery and insufficient/missing input supply the SMB136 can

run its switching regulator in reverse to support “Low Battery Recovery”

mode (+4.17V @ 500mA) or USB “On the Go” power (+5.0V @

500mA).

Charge control includes input current limit (supporting USB2.0), trickle

charge, pre-charge, constant current/constant voltage, float voltage

and termination/safety settings that are fully programmable via a serial

I

a flexible solution. Fast charge current level can be set via I

by the input current settings). An Enable (EN) pin is also provided for

suspending charging and/or sleep mode. Built-in reverse-current

blocking prevents inadvertent cell discharge.

The SMB136 also offers a wide variety of features that protect the

battery pack as well as the charger and input circuitry: over-current,

under/over-voltage, safety timers and thermal protection. Accurate

1.0% battery float voltage control ensures complete charging and

improves battery capacity utilization. Status can be monitored via the

serial port for charge state and fault conditions. In addition, the STAT

output can be used to signal charge status. Operating voltage is

specified from +4.35V to +6.2V with +18V non-operating input

tolerance.

The SMB136 is available in an ultra-compact CSP-30

package and is rated over the –30C to +85C temperature range.

SYSTEM APPLICATION

FEATURES & APPLICATIONS

Handheld Device

I2C (optional)

SMB136

Li- Ion

Charging Current

up to 1500mA

USB

System Output

up to 1400mA

USB-OTG

5.0V @ 500mA

OTG/LBR

750mA

LBR Output

5.0V @ 500mA

USB or AC Input

100/500/700-1400mA

"Ideal Diode"

Current

Total Sys. Output

>1400mA

USB

USB

USB

500mA

4.35V-5.5V

AC/DC

300-1800mA

4.5V-6.0V

Figure 1 – Using the SMB136 to charge a single cell Li+ battery from USB or AC Adapter power sources

*Patent Pending