High current synchrous switcher based charger chip

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What's New Abstracts:
Power Management:
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TI Battery Management IC Provides Faster and Cooler Charging in Portable Li-Ion Powered Applications
DALLAS (July 12, 2004) ? Solving the design challenge to efficiently deliver higher battery charge current in small portable applications, Texas Instruments Incorporated announced today the first synchronous, switch-mode battery charge integrated circuit (IC) with internal power FETs capable of supplying up to 2 A of charge current. The new battery management IC enables higher charge current while reducing the amount of heat generated, making it ideal for use in systems that incorporate one-, two- and three-series cell lithium-ion(Li-Ion) or lithium-polymer (Li-Poly) battery packs, such as portable DVD and media players, smart handhelds, medical, industrial and other portable equipment. (See www.ti.com/sc04147).

http://focus.ti.com/docs/pr/pressrelease.jhtml?prelId=sc04147

Tiny Switch-Mode, Battery Charger IC with Integrated FETs Delivers up to 2 A in Applications such as Portable DVD Players, Handhelds

DALLAS (July 12, 2004) - Solving the design challenge to efficiently deliver higher battery charge current in small portable applications, Texas Instruments Incorporated (TI) (NYSE: TXN) announced today the first synchronous, switch-mode battery charge integrated circuit (IC) with internal power FETs capable of supplying up to 2 A of charge current. The new battery management IC enables higher charge current while reducing the amount of heat generated, making it ideal for use in systems that incorporate one-, two- and three-series cell lithium-ion (Li-Ion) or lithium-polymer (Li-Poly) battery packs, such as portable DVD and media players, smart handhelds, medical, industrial and other portable equipment. (See www.ti.com/sc04147.)

TI's bq24100 battery charge IC, which comes in a small 3.5 mm x 4.5 mm QFN package, operates at a fixed frequency of 1.1 MHz from an input voltage up to 16 V. The new IC delivers high accuracy current and voltage regulation for precise battery charging, multiple charge status outputs for charge progress indication and automatic battery full charge detection and charge termination.

Providing safe and reliable charging of Li-Ion or Li-Polymer batteries, the bq24100 device charges in three phases: a low current conditioning phase for deeply discharged batteries, a fast charge constant current phase delivering up to 2 A and a constant voltage phase. In this final phase, the device terminates charge based on a minimum current level. A programmable charge timer provides a safety backup for termination. Separate versions of the IC also allow the portable system's micro-controller to control the battery charging profile and termination with digital inputs to the IC. The bq24100 automatically re-starts the charge if the battery voltage falls below a specific threshold.

As with other TI battery charge management devices, including the popular bqTINYTM family of linear control charge ICs, the new bq24100 integrates reverse-blocking protection to prevent battery drainage through the IC in the absence of the input charging supply.


Key Specifications of the bq24100:

Integrated Synchronous, 1.1 MHz Fixed-Frequency PWM Controller
Integrated PowerFETs for up to 2 A Charge Rate
High Accuracy Voltage and Current Regulation
Offered in Standalone (Built-in Charge Management and Control) and System-Controlled Versions
Status Outputs for LED or Host Processor Interface
20 V Input Voltage Rating
High-Side Current Sensing
Battery Temperature Monitoring
Automatic Sleep Mode for Low Power Consumption



Available Today

The bq24100 is currently shipping in volume from TI and its authorized distributors, and is available in a 20-pin, 3.5 mm x 4.5 mm QFN package. Suggested resale price for the charge IC is $2.10 each per 1,000 units. A bq24100 evaluation module, application notes, technical documentation and TI´s Power Management selection guide are available at power.ti.com.


Datasheet is here:
http://focus.ti.com/lit/ds/symlink/bq24100.pdf

Hi again Newbie,

Looks very interesting. Im wondering if there is an
NiMH mode with that chip.
Did you check the pin spacing...what spacing does it
happen to have or is it available in standard dip pack?

Take care,
Al

It is rather tiny, there is not much call for those monster chips we used to use in the Dual Inline Package.

Pin spacing between pin centers is 0.5 mm


There are alot of other switching chargers, many for multi-chemistry, in larger packages, DIP and SOIC.

Take a look:

TI switching charger chips.

Hi again,

OH yes, thanks. I looked at a few, they got pretty
sophisticated -- looks like a microcontroller internally
to most of them.

I was thinking of going PIC on the chargers...
Kickin some ideas around.

Take care,
Al

There is the Atmel AVR Butterfly (19 dollars as I recall), which you could tack on your own circuit. Then there is their switcher circuit for battery chargers, and even source code. The AVR Butterfly gives you an STN LCD screen, 4 direction joystick with push button, light and temperature sensors, one of the five A/D channels is set to read voltage, additional external serial 4M bit flash storage, piezo speaker, program through UART, and coin cell battery for power to work with.

Digi-Key Part Number ATAVRBFLY-ND
http://www.digikey.com/scripts/DkSearch/dksus.dll?Detail?Ref=19115&Row=204416&Site=US

More info here:
http://www.atmel.com/dyn/resources/prod_documents/doc4271.pdf

Hello again Newbie,

OH yes, pretty cool. I'll need better then 0.1 volt
resolution however. Was hoping for at least as good
as 0.001 volt for that, with maybe a range of 1 or
2 volts.


Take care,
Al

If you utilize an external 4.096V as your reference, the A/D channels can be run as 10-bit converters, for a 0.004 V resolution. Or you can utilize a 2.5V reference reference for 0.0024V resolution. Or use a 1.024V external reference for 0.001 V resolution.

Such as these parts:

http://www.national.com/pf/LM/LM4040.html

or these:

http://www.national.com/pf/LM/LM4041.html

Hi again,

Are we talking about the same thing?
All i can find is 'Voltage Readings' accuracy of "0.1 volts".
Cant find any a/d channels...
What page is that on?

Take care,
Al

Take a look at the chip that is utilized in it, the ATMEGA169V:

16-Kbyte self-programming Flash Program Memory, 1-Kbyte SRAM, 512 Byte EEPROM, 8 Channel 10-bit A/D-converter. JTAG interface for on-chip-debug. 4 X 25 Segment LCD Driver. Up to 16 MIPS throughput at 16 MHz. 5 Volt Operation.
1.8V version: ATmega169V

http://www.atmel.com/dyn/resources/prod_documents/doc2514.pdf

Go to page 194 and you'll see:

• 10-bit Resolution
• 0.5 LSB Integral Non-linearity
• ± 2 LSB Absolute Accuracy
• 13 µs - 260 µs Conversion Time (50 kHz to 1 MHz ADC clock)
• Up to 15 kSPS at Maximum Resolution (200 kHz ADC clock)
• Eight Multiplexed Single Ended Input Channels
• Optional Left Adjustment for ADC Result Readout
• 0 - V CC ADC Input Voltage Range
• Selectable 1.1V ADC Reference Voltage
• Free Running or Single Conversion Mode
• ADC Start Conversion by Auto Triggering on Interrupt Sources
• Interrupt on ADC Conversion Complete
• Sleep Mode Noise Canceler

The ATmega169 features a 10-bit successive approximation ADC. The ADC is connected to an 8-channel Analog Multiplexer which allows eight single-ended voltage inputs constructed from the pins of Port F. The single-ended voltage inputs refer to 0V (GND).
The ADC contains a Sample and Hold circuit which ensures that the input voltage to the ADC is held at a constant level during conversion. A block diagram of the ADC is shown
in Figure 82.

The ADC has a separate analog supply voltage pin, AVCC. AVCC must not differ more than ± 0.3V from VCC . See the paragraph “ADC Noise Canceler” on page 201 on how to connect this pin.

Internal reference voltages of nominally 1.1V or AVCC are provided On-chip. The voltage reference may be externally decoupled at the AREF pin by a capacitor for better noise performance.

10 bit converter....
Add external reference....

Hello again,

Oh ok, you were referring to the chip itself.
Yes, the first page has 8 channel 10bit a/d on it

Thanks for the info!

Take care,
Al

Yup. It is a nice little cheap platform, pre-built, with a LCD display, speaker, joystick and many other things, that is great to modify for whatever use you see fit.