Specifications

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OBSOLETE

LM3647

www.ti.com

SNOS517H –MARCH 2000–REVISED APRIL 2013

LM3647 Universal Battery Charger for Li-Ion, Ni-MH and Ni-Cd Batteries

Check for Samples: LM3647

FEATURES

DESCRIPTION

The LM3647 is a charge controller for Lithium-Ion (Li-

• Auto-Adaptive Fast Charge

Ion), Nickel-Metal Hydride (Ni-MH) and Nickel-

• High-Resolution, Accurate Voltage Monitoring

Cadmium (Ni-Cd) batteries. The device can use

Prevents Li-Ion Undercharge or Overcharge

either a pulsed-current charging or a constant-current

• Fast Charge, Pre-Charge and Maintenance

charging technique. The device can also be

configured to discharge before charging. Throughout

Currents are Provided. Different Currents are

the charging sequence the LM3647 monitors voltage

Selectable via External Resistors

and/or temperature and time in order to terminate

• Fast-Charge Termination by Δ Temperature/Δ

charging.

Time, Maximum Voltage, Maximum

Charge Termination Methods are:

Temperature, Negative Δ Voltage and

Maximum Time

• Negative Delta Voltage (−ΔV)

• Optional: Delta Temperature/Delta Time (ΔT/Δt)

• Dynamically Detects Battery Insertion,

Removal, Short Circuit and Bad Battery

• Backup: Maximum Temperature

Without Additional Hardware

• Backup: Maximum Time

• Supports Charging of Battery Packs with 2–8

• Backup: Maximum Voltage

Cells of Ni-Cd/Ni-MH or 1–4 Cells of Li-Ion (1

If both voltage and temperature fail to trigger the

Cell of NiCd/NiMH can be Supported by Added

termination requirements, then the maximum time

External 2x Voltage Amplifier)

(configured by external hardware) steps in which

• Three Optional LED Indicators and Buzzer

terminates the charging.

Output Indicate Operational Modes

In Ni-Cd/Ni-MH mode, four different charging stages

• Ni-MH/Ni-Cd Charge Mode, Li-Ion Charge Mode

are used:

or Discharge Mode can be Selected Manually

• Soft-Start Charge

• Supports Control of Current Feedback Power

• Fast Charge

Supply and Constant Current Power Supply

• Topping Charge

• Maintenance Charge

APPLICATIONS

In Li-Ion mode, four different charging stages are

• Battery Charging Systems for:

used:

– Portable Consumer Electronics

• Qualification

– Audio/Video Equipment

• Fast Charge Phase 1, Constant Current

– Communications Equipment

• Fast Charge Phase 2, Constant Voltage

– Point of Sale Devices

• Maintenance Charge

– Power Tools

The charge current of the LM3647 is configured via

– Personal Convenience Products

external resistors, which in turn controls the duty

cycle of the PWM switching control output. For cost-

sensitive applications, the LM3647 charge controller

cab be configured to use an external current source

and no temperature sensor.

Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of

Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.

2All trademarks are the property of their respective owners.

PRODUCTION DATA information is current as of publication date.

Products conform to specifications per the terms of the Texas

Instruments standard warranty. Production processing does not

necessarily include testing of all parameters.

Summary of content (19 pages)

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OBSOLETE LM3647 www.ti.com SNOS517H – MARCH 2000 – REVISED APRIL 2013 LM3647 Universal Battery Charger for Li-Ion, Ni-MH and Ni-Cd Batteries Check for Samples: LM3647 FEATURES DESCRIPTION • • The LM3647 is a charge controller for Lithium-Ion (LiIon), Nickel-Metal Hydride (Ni-MH) and NickelCadmium (Ni-Cd) batteries. The device can use either a pulsed-current charging or a constant-current charging technique. The device can also be configured to discharge before charging.
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OBSOLETE LM3647 SNOS517H – MARCH 2000 – REVISED APRIL 2013 www.ti.com DESCRIPTION (CONTINUED) When using an external current source, the current is controlled by the LM3647 which turns the current source on and off. The LM3647 automatically detects the presence of a battery and starts the charging procedure when the battery is installed. Whenever an error occurs (e.g., short circuit, temperature too high, temperature too low, bad battery, charge time over, and so on.
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OBSOLETE LM3647 www.ti.
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OBSOLETE LM3647 SNOS517H – MARCH 2000 – REVISED APRIL 2013 www.ti.com These devices have limited built-in ESD protection. The leads should be shorted together or the device placed in conductive foam during storage or handling to prevent electrostatic damage to the MOS gates. ABSOLUTE MAXIMUM RATINGS (1) (2) Supply Voltage (VCC) 7V −0.3V to VCC +0.
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OBSOLETE LM3647 www.ti.com SNOS517H – MARCH 2000 – REVISED APRIL 2013 FUNCTIONAL DESCRIPTION GENERAL The LM3647 can be configured to charge three different types of batteries: Ni-Cd, Ni-MH and Li-Ion. The charger behavior for Ni-Cd and Ni-MH is similar but the charge curves will appear slightly different due to the differences in chemistry.
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OBSOLETE LM3647 SNOS517H – MARCH 2000 – REVISED APRIL 2013 www.ti.com ADVANCED PIN DESCRIPTIONS SEL1 is a selection pin to control the LM3647 discharge and maintenance charge modes. The pin has three states: tied to VCC, GND, or unconnected (Hi-Z). When the charger is configured to charge Ni-Cd or Ni-MH batteries, this pin determines if the charger discharges the battery before charging or if the charger shall only maintenance charge the battery.
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OBSOLETE LM3647 www.ti.com SNOS517H – MARCH 2000 – REVISED APRIL 2013 RESET is a reset pin. LED1 is an active-low output used to indicate charge phase. It is also used when measuring the charge timeout value. LED2 is an active-low output used to indicate charge or discharge. It also sends out digitally what the LM3647 has read at the mode selection pins and charge timeout. LED3 is an active-low output used to indicate charge start/stop and error. VREF is the voltage reference analog input.
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OBSOLETE LM3647 SNOS517H – MARCH 2000 – REVISED APRIL 2013 www.ti.com Table 2. Resistor network selection Quick Guide No. of Cells Ni-Cd/Ni-MH Nominal Max R6 R7 2 2.4V 3.7V 10k 43k 3 3.6V 5.55V 47k 56k 4 4.8V 7.4V 16k 11k 5 6V 9.25V 62k 30k 6 7.2V 11.1V 15k 5.6k 7 8.4V 12.95V 27k 8.2k 8 9.6V 14.8V 39k 10k 9 10.8V 16.65V 68k 15k 10 12V 18.5V 22k 3.
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OBSOLETE LM3647 www.ti.com SNOS517H – MARCH 2000 – REVISED APRIL 2013 LI-ION The voltage divider network for Li-Ion must be selected with great care for maximum utilization of the batteries. Li-Ion battery cells have a nominal voltage of 3.6V or 3.7V and the maximum voltage per cell is specified at 4.1V or 4.2V respectively. By multiplying the number of battery cells with the maximum cell voltage, it is possible to determine the Maximum Voltage of the Battery Pack.
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OBSOLETE LM3647 SNOS517H – MARCH 2000 – REVISED APRIL 2013 www.ti.com CHARGE TIMEOUT The LM3647 uses the charge timeout value as a backup termination method if the normal termination methods fail. The charge timeout also controls the length of some of the phases, (for example, the Topping Charge phase).
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OBSOLETE LM3647 www.ti.com SNOS517H – MARCH 2000 – REVISED APRIL 2013 With a current feedback power supply the PWM pin must be configured for “fast” mode (SEL3 = VCC; if SEL2 = GND or VCC; automatic if SEL2 = open). The RC-network R6, C9 and R5, C1||C2 lowpass-filters the PWM-signal from the LM3647 to a DC-level that is fed into the operational amplifier. The resistor R22 is required to prevent DC-output before the LM3647 has control of the RC-networks.
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OBSOLETE LM3647 SNOS517H – MARCH 2000 – REVISED APRIL 2013 www.ti.com DIMENSIONING THE RESET CIRCUITRY The reset-circuitry is designed to hold the RESET pin low until the power supply to the LM3647 has stabilized. The RC-network (R21 and C4) should be dimensioned in the following way: (R21 × C4) > 5×PowerSupplyRiseTime (7) The diode D2 discharges the capacitance C4 when power loss occurs. The resistor R20 is used to protect the SYSOK-pin, and its value is not critical (typical value is 2 kΩ).
PAGE 13
OBSOLETE LM3647 www.ti.com SNOS517H – MARCH 2000 – REVISED APRIL 2013 BUZZER OUTPUT CIRCUITRY The buzzer-circuitry turns the transistor Q3 on when the buzzer should sound. If the current consumption for the buzzer is lower than 0.3 mA then the buzzer may be directly connected to the BUZZER-pin. Please note that the BUZZER-pin does not generate a PWM-signal, therefore the buzzer must have its own oscillator circuitry.
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OBSOLETE LM3647 SNOS517H – MARCH 2000 – REVISED APRIL 2013 www.ti.com Table 5.
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OBSOLETE LM3647 www.ti.com SNOS517H – MARCH 2000 – REVISED APRIL 2013 TYPICAL CIRCUIT CONFIGURATIONS Figure 6.
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OBSOLETE LM3647 SNOS517H – MARCH 2000 – REVISED APRIL 2013 www.ti.com Figure 7.
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OBSOLETE LM3647 www.ti.com SNOS517H – MARCH 2000 – REVISED APRIL 2013 Figure 8. Circuitry Used for Li-Ion NOTE D7 is required to protect Q4 from reverse current. Can also be used for Ni-Cd and Ni-MH if those chemistries are to be supported with the same charger.
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OBSOLETE LM3647 SNOS517H – MARCH 2000 – REVISED APRIL 2013 www.ti.com REVISION HISTORY Changes from Revision G (April 2013) to Revision H • 18 Page Changed layout of National Data Sheet to TI format ..........................................................................................................
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