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uc2906.pdf

Ładowarka akumulatorów z UC3906 – błędy w schemacie z Praktycznego Elektronika 9/98

Najpierw zrobiłem ją jak w praktycznym elektroniku ale nie działała dobrze potem ja przebudowałem i działała nieźle ale włączała sie przy za niskim napięciu akumulatora. Na koniec przebudowałem układ na 3 stopniową ładowarkę jak poleca producent i to był dobry pomysł. Muszę nad nią jeszcze posiedzieć ale ładuje akumulatory super. Trzy stopnie ładowania doładowują akumulator na maksimum. Jak ją dokończę to dam schemat. Odnośnie obliczeń to polecam kartę katalogową układu UC2906 czyli to samo co UC3906 z korekcja temperaturową. W karcie producent podaje jak dobrać wartości rezystorów do własnej ładowarki :D


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UC2906
UC3906

Sealed Lead-Acid Battery Charger
FEATURES

DESCRIPTION

• Optimum Control for Maximum
Battery Capacity and Life

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 batteries. 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.

• Internal State Logic Provides
Three Charge States
• Precision Reference Tracks
Battery Requirements Over
Temperature

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

• Controls Both Voltage and
Current at Charger Output
• System Interface Functions

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 supply 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.

• Typical Standby Supply Current
of only 1.6mA

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 indicate output and over-charge terminate input.

BLOCK DIAGRAM
SINK

SOURCE

COMPENSATION

16

15

14

DRIVER
+VIN CURRENT
LIMIT
250 mV

VOLTAGE
AMPLIFIER

C/S +

3

C/S -

2

11

CURRENT
SENSE

5

VREF

6

VREF

OVER-CHARGE
INDICATE

7

Q

R
OVER-CHARGE
TERMINATE

STATE LEVEL
CONTROL

ENABLE
COMPARATOR

UV
SENSE
POWER
INDICATE

10

HIGH 0.95 VREF
LOW 0.90 VREF
VREF 2.3 V
at -3.5 mV/C

GND

CHARGE
ENABLE

VREF
SENSE
COMPARATOR

25 mV

+VIN

TRICKLE
BIAS

12

1

VOLTAGE
SENSE

+

C/S OUT

+

4

13

9

C/L

8

S

SLUS186B - SEPTEMBER 1996 - REVISED JULY 2003

Q

R

L1

L2
S

UC2906
UC3906
CONNECTION DIAGRAMS

ABSOLUTE MAXIMUM RATINGS
Supply Voltage (+VIN) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40V
Open Collector Output Voltages . . . . . . . . . . . . . . . . . . . . . 40V
Amplifier and Comparator Input Voltages . . . . . . –0.3V to +40V
Over-Charge Terminate Input Voltage . . . . . . . . –0.3V to +40V
Current Sense Amplifier Output Current. . . . . . . . . . . . . . 80mA
Other Open Collector Output Currents . . . . . . . . . . . . . . . 20mA
Trickle Bias Voltage Differential with respect to VIN . . . . . –32V
Trickle Bias Output Current . . . . . . . . . . . . . . . . . . . . . . –40mA
Driver Current . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80mA
Power Dissipation at TA = 25°C (Note 2) . . . . . . . . . . . 1000mW
Power Dissipation at TC = 25°C (Note 2). . . . . . . . . . . 2000mW
Operating Junction Temperature . . . . . . . . . . –55°C to +150°C
Storage Temperature . . . . . . . . . . . . . . . . . . . –65°C to +150°C
Lead Temperature (Soldering, 10 Seconds) . . . . . . . . . . 300°C

PLCC-20, LCC-20 (TOP VIEW)
Q, L Packages

PIN FUNCTION
N/C
C/S OUT
C/SC/S+
C/L
N/C
+VIN
GROUND
POWER INDICATE
OVER CHARGE TERMINATE
N/C
OVER CHARGE INDICATE
STATE LEVEL CONTROL
TRICKLE BIAS
CHARGE ENABLE
N/C
VOLTAGE SENSE
COMPENSATION
DRIVER SOURCE
DRIVER SINK

Note 1: Voltages are referenced to ground (Pin 6). Currents
are positive into, negative out of, the specified terminals.
Note 2: Consult Packaging section of Databook for thermal
limitations and considerations of packages.

DIL-16, SOIC-16 (TOP VIEW)
J or N Package, DW Package

PIN
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20

ELECTRICAL CHARACTERISTICS: Unless otherwise stated, these specifications apply for TA = –40°C to +70°C for the
UC2906 and 0°C to +70°C for the UC3906, +VIN = 10V, TA = TJ.
PARAMETER

TEST CONDITIONS

UC2906
MIN

UC3906

TYP

MAX

1.6

3.3

1.8

3.6

4.5

4.8

0.20

0.30

2.3

2.325

3

8

MIN

UNITS

TYP

MAX

1.6

3.3

mA

1.8

3.6

mA

4.5

4.8

V

0.20

0.30

V

2.3

2.330

V

3

8

mV

Input Supply
Supply Current

+VIN = 10V
+VIN = 40V

Supply Under-Voltage Threshold +VIN = Low to High

4.2

Supply Under-Voltage
Hysteresis

4.2

Internal Reference (VREF)
Voltage Level (Note 3)

Measured as Regulating Level at
Pin 13 w/ Driver Current = 1mA,
TJ = 25°C

Line Regulation

+VIN = 5 to 40V

Temperature Coefficient

2.275

–3.5

2

2.270

–3.5

mV/°C

UC2906
UC3906
ELECTRICAL CHARACTERISTICS: Unless otherwise stated, these specifications apply for TA = –40°C to +70°C for the
UC2906 and 0°C to +70°C for the UC3906, +VIN = 10V, TA = TJ.
PARAMETER

TEST CONDITIONS

UC2906
MIN

TYP

UC3906
MAX

MIN

TYP

UNITS
MAX

Voltage Amplifier
µA

Input Bias Current

Total Input Bias at Regulating Level

–0.5

–0.2

–0.5

–0.2

Maximum Output Current

Source

–45

–30

–15

–45

–30

–15

µA

90

30

60

90

µA

50

65

dB

0.2

V

Sink

30

60

Open Loop Gain

Driver current = 1mA

50

65

Output Voltage Swing

Volts above GND or below +VIN

0.2

Minimum Supply to Source
Differential

Pin 16 = +VIN, IO = 10mA

2.0

Maximum Output Current

Pin 16 to Pin 15 = 2V

Driver

25

Saturation Voltage

2.2

40

2.0
25

2.2

40

V
mA

0.2

0.45

0.2

0.45

V

0.2

1.0

0.2

1.0

µA

Current Limit Amplifier
Input Bias Current
Threshold Voltage

225

+VIN = 5 to 40V

250

275

0.03

Offset below +VIN

Threshold Supply Sensitivity

0.25

225

250

275

mV

0.03

0.25

%/V

Voltage Sense Comparator
Threshold Voltage

0.94

0.949

0.960

0.94

0.949

0.960

V/V

As a function of VREF, L1 = SET
Input Bias Current

As a function of VREF, L1 = RESET

0.895

0.90

0.910

0.895

0.90

0.910

V/V

Total Input Bias at Thresholds

–0.5

–0.2

–0.5

–0.2

µA

Current Sense Comparator
Input Bias Current

0.1
0.01

Input Offset Current
Input Offset Voltage

Referenced to Pin 2, IOUT = 1mA

Offset Supply Sensitivity

20

+VIN = 5 to 40V

30

0.01
20

0.5
0.2

µA

25

30

mV

0.05

VOUT = 2V

Output Saturation Voltage

0.2

25

µA

0.1

IOUT = 10mA

25

0.35

0.05

0.35

%/V

0.05

Offset Common Mode Sensitivity CMV = 2V to +VIN
Maximum Output Current

0.5

0.35

0.05

0.35

%/V

40

25

0.2

0.45

0.99

1.0

1.01

–0.5
25

40

mA

0.2

0.45

V

0.99

1.0

1.01

V/V

–0.2

–0.5

–0.2

µA

40

25

40

mA

Enable Comparator
Threshold Voltage

As a function of VREF

Input Bias Current
Trickle Bias Maximum Output
Current

VOUT = +VIN − 3V

Trickle Bias Maximum Output
Voltage

Volts below +VIN, IOUT = 10mA

Trickle Bias Reverse Hold-Off
Voltage

+VIN = 0V, IOUT = –10µA

2.0
6.3

7.0

0.7

1.0

2.6

2.0
6.3

7.0

0.7

1.0

2.6

V
V

Over-Charge Terminate Input
Threshold Voltage
Internal Pull-Up Current

At Threshold

1.3

1.3

V

10

10

µA

5

mA

Open Collector Outputs (Pins 7, 9, and 10)
Maximum Output Current

VOUT = 2V

2.5

5

2.5

Leakage Current

IOUT = 1.6mA

0.25

0.45

0.25

0.45

V

IOUT = 50µA

Saturation Voltage

0.03

0.05

0.03

0.05

V

VOUT = 40V

1

3

1

3

µA

Note 3. The reference voltage will change as a function of power dissipation on the die according to the temperature coefficient of
the reference and the thermal resistance, junction-to-ambient.

3

UC2906
UC3906
OPERATION AND APPLICATION INFORMATION
the charger a low current turn on mode. The output current of the charger is limited to a low-level until the battery reaches a specified voltage, preventing a high
current charging if a battery cell is shorted. Figure 2
shows the state diagram of the charger. Upon turn on
the UV sense circuitry puts the charger in state 1, the
high rate bulk-charge state. In this state, once the enable
threshold has been exceeded, the charger will supply a
peak current that is determined by the 250mV offset in
the C/L amplifier and the sensing resistor RS.
To guarantee full re-charge of the battery, the charger’s
voltage loop has an elevated regulating level, VOC, during state 1 and state 2. When the battery voltage
reaches 95% of VOC, the charger enters the over-charge
state, state 2. The charger stays in this state until the
OVER-CHARGE TERMINATE pin goes high. In Figure 1,
the charger uses the current sense amplifier to generate
this signal by sensing when the charge current has tapered to a specified level, IOCT. Alternatively the
over-charge could have been controlled by an external
source, such as a timer, by using the OVER-CHARGE
INDICATE signal at Pin 9. If a load is applied to the battery and begins to discharge it, the charger will contribute its full output to the load. If the battery drops 10%
below the float level, the charger will reset itself to state
1. When the load is removed a full charge cycle will follow. A graphical representation of a charge, and discharge, cycle of the dual lever float charger is shown in
Figure 3.

Internal reference temperature characteristic and
tolerance.
Dual Level Float Charger Operations
The UC2906 is shown configured as a dual level float
charger in Figure 1. All high currents are handled by the
external PNP pass transistor with the driver supplying
base drive to this device. This scheme uses the TRICKLE
BIAS output and the charge enable comparator to give

Figure 1. The UC2906 in a dual level float charger.
4

OPERATION AND APPLICATION INFORMATION (cont.)

UC2906
UC3906

Design Procedure
1) Pick divider current, ID. Recommended value is
50 A to 100 A.
2)

RC = 2 .3V / ID

3)

RA + RB = RSUM = (VF – 2 .3V ) / ID

4)

RD = 2 .3V • RSUM / (VOC – VF )

5)

RA = (RSUM + RX )(1– 2 .3V / VT )

WHERE : RX = RC • RD / (RC + RD )

6)

RB = RSUM − RA

7)

RS = 0.25V / IMAX

8)

RT = (VIN – VT – 2 .5V ) / IT

9)

IOCT =

IMAX
10

Note: V12 = 0.95VOC ,
.
V 31 = 0.90VF ,
For further design and application information see
UICC Application Note U-104

Figure 2. State diagram and design equations for the dual level float charger.

Explanation: Dual Level Float Charger
A.
B.
C.
D.

Input power turns on, battery charges at trickle current E.
rate.
Battery voltage reaches VT enabling the driver and turning off the trickle bias output, battery charges at lMAX
F.
rate.
Transition voltage V12 is reached and the charger indiG.
cates that it is now in the over-charge state, state 2.
Battery voltage approaches the over-charge level VOC
and the charge current begins to taper.

Charge current tapers to lOCT. The current sense amplifier output, in this case tied to the OC TERMINATE input, goes high. The charger changes to the float state
and holds the battery voltage at VF.
Here a load ( & gt; lMAX) begins to discharge the battery.
The load discharges the battery such that the battery
voltage falls below V31. The charger is now in state 1,
again.

Figure 3. Typical charge cycle: UC2906 dual level float charger.
5

UC2906
UC3906
OPERATION AND APPLICATION INFORMATION (cont.)
tions a series resistor, or external buffering transistor,
may be required at the current sense output to prevent
excessive power dissipation on the UC2906.

Compensated Reference Matches Battery
Requirements
When the charger is in the float state, the battery will be
maintained at a precise float voltage, VF. The accuracy of
this float state will maximize the standby life of the battery
while the bulk-charge and over-charge states guarantee
rapid and full re-charge. All of the voltage thresholds on
the UC2906 are derived from the internal reference. This
reference has a temperature coefficient that tracks the
temperature characteristic of the optimum-charge and
hold levels for sealed lead-acid cells. This further guarantees that proper charging occurs, even at temperature extremes.

A PNP Pass Device Reduces Minimum Input to Output Differential
The configuration of the driver on the UC2906 allows a
good bit of flexibility when interfacing to an external pass
transistor. The two chargers shown in Figures 1 and 4
both use PNP pass devices, although an NPN device
driven from the source output of the UC2906 driver can
also be used. In situations where the charger must operate with low input to output differentials the PNP pass device should be configured as shown in Figure 4. The PNP
can be operated in a saturated mode with only the series
diode and sense resistor adding to the minimum differential. The series diode, D1, in many applications, can be
eliminated. This diode prevents any discharging of the
battery, except through the sensing divider, when the
charger is attached to the battery with no input supply
voltage. If discharging under this condition must be kept
to an absolute minimum, the sense divider can be referenced to the POWER INDICATE pin, Pin 7, instead of
ground. In this manner the open collector off state of Pin
7 will prevent the divider resistors from discharging the
battery when the input supply is removed.

Dual Step Current Charger Operation
Figures 4, 5 and 6 illustrate the UC2906’s use in a different charging scheme. The dual step current charger is
useful when a large string of series cells must be
charged. The holding-charge state maintains a slightly elevated voltage across the batteries with the holding current, 1H. This will tend to guarantee equal charge
distribution between the cells. The bulk-charge state is
similar to that of the float charger with the exception that
when V12 is reached, no over-charge state occurs since
Pin 8 is tied high at all times. The current sense amplifier
is used to regulate the holding current. In some applica-

Figure 4. The UC2906 in a dual step current charger.
6

UC2906
UC3906
OPERATION AND APPLICATION INFORMATION (cont.)

Figure 5. State Diagram and design equations for the dual step current charger.

Explanation: Dual Step Current Charger
A.
B.

C. An external load starts to discharge the battery.
D: When VF is reached the charger will supply the full current IMAX + IH.
E. The discharge continues and the battery voltage reaches
V21 causing the charger to switch back to state 1.

Input power turns on, battery charges at a rate of IH +
IMAX.
Battery voltage reaches V12 and the voltage loop
switches to the lower level VF. The battery is now fed with
the holding current IH.

Figure 6. Typical charge cycle: UC2906 dual step current charger

7

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