Sealed Lead Acid Battery Charger FEATURES Optimum Control for Maximum

Texas Instruments, Incorporated [Slus186, B]

Description

Niveau: Supérieur, Doctorat, Bac+8
UC2906 UC3906 application INFO available Sealed Lead-Acid Battery Charger FEATURES • Optimum Control for Maximum Battery Capacity and Life • Internal State Logic Provides Three Charge States • Precision Reference Tracks Battery Requirements Over Temperature • Controls Both Voltage and Current at Charger Output • System Interface Functions • Typical Standby Supply Current of only 1.6mA DESCRIPTION The UC2906 series of battery charger controllers contains all of the necessary circuitry to optimally control the charge and hold cycle for sealed lead-acid bat- teries. These integrated circuits monitor and control both the output voltage and current of the charger through three separate charge states; a high current bulk-charge state, a controlled over-charge, and a precision float-charge, or standby, state. Optimum charging conditions are maintained over an extended temperature range with an internal reference that tracks the nominal temperature characteris- tics of the lead-acid cell. A typical standby supply current requirement of only 1.6mA allows these ICs to predictably monitor ambient temperatures. Separate voltage loop and current limit amplifiers regulate the output voltage and current levels in the charger by controlling the onboard driver. The driver will sup- ply at least 25mA of base drive to an external pass device. Voltage and current sense comparators are used to sense the battery condition and respond with logic inputs to the charge state logic. A charge enable comparator with a trickle bias output can be used to implement a low current turn-on mode of the charger, preventing high current charging during abnormal conditions such as a shorted battery cell.

• max min


• output current


• charge


• comparator input


• µa


• voltage sense


• typ max

Sujets

• Régulation
• Charge

Informations

• Publié par: profil-zyak-2012
• Nombre de lectures: 49
• Langue: English

Extrait

UV SENSE

5

POWER INDICATE

OVERCHARGE INDICATE

+VIN

VREF

VREF 2.3 V at 3.5 mV/C

C/S 

C/L

C/S OUT

3

2

1

CURRENT SENSE

25 mV

CURRENT +VIN LIMIT 250 mV 4

9

STATE LEVEL 10 CONTROL

CHARGE 12 ENABLE

ENABLE COMPARATOR

VREF

Precision Reference Tracks Battery Requirements Over Temperature

Typical Standby Supply Current of only 1.6mA

VOLTAGE AMPLIFIER

SINK SOURCE 16 15 DRIVER

HIGH 0.95 VREF LOW 0.90 VREF

C/S +

BLOCK DIAGRAM

Internal State Logic Provides Three Charge States

application INFO available

DESCRIPTION The UC2906 series of battery charger controllers contains all of the necessary circuitry to optimally control the charge and hold cycle for sealed leadacid bat teries. These integrated circuits monitor and control both the output voltage and current of the charger through three separate charge states; a high current bulkcharge state, a controlled overcharge, and a precision floatcharge, or standby, state.

SLUS186B  SEPTEMBER 1996  REVISED JULY 2003

7

8

OVERCHARGE TERMINATE

R Q L1 S

VOLTAGE 13 SENSE

TRICKLE 11 BIAS

Sealed LeadAcid Battery Charger

VREF SENSE COMPARATOR

COMPENSATION 14

Controls Both Voltage and Current at Charger Output

System Interface Functions

UC2906 UC3906

FEATURES
Optimum Control for Maximum Battery Capacity and Life

Other features include a supply undervoltage sense circuit with a logic output to indicate when input power is present. In addition the overcharge state of the charger can be externally monitored and terminated using the overcharge indi cate output and overcharge terminate input.

Optimum charging conditions are maintained over an extended temperature range with an internal reference that tracks the nominal temperature characteris tics of the leadacid cell. A typical standby supply current requirement of only 1.6mA allows these ICs to predictably monitor ambient temperatures.

6

GND

Separate voltage loop and current limit amplifiers regulate the output voltage and current levels in the charger by controlling the onboard driver. The driver will sup ply at least 25mA of base drive to an external pass device. Voltage and current sense comparators are used to sense the battery condition and respond with logic inputs to the charge state logic. A charge enable comparator with a trickle bias output can be used to implement a low current turnon mode of the charger, preventing high current charging during abnormal conditions such as a shorted battery cell.

R Q L2 S