NJW4120
-
1
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Lithium-ion Battery Charger Controller IC with Timer
■GENERAL DESCRIPTION ■PACKAGE OUTLINE
■FEATURES
● Charge Control Feedback by Photocoupler
● Adjustable Charge Voltage
● Adjustable Pre-Charge and Full Charge Current
● Temperature Monitor
● Over Charge Timer
● Internal Re-Charge function
● Delay timers and Hysteresis inputs for high noise immunity
● Over Discharge Battery Detect
● Over Voltage Protection
● Bi-CMOS Technology
● Package Outline NJW4120M : DMP20
NJW4120V : SSOP20
■PIN CONFIGURATION
NJW4120 is a 1-cell and 2-cell lithium ion battery charge control I
C
with a built-in AC-DC secondary side control feature. Using
a
photocoupler to directly feed back optimum charging voltage and
current information to the primary side, it increases energ
y
efficiency, makes possible a smaller charger, and conserve
s
energy. Charging current can be freely set and therefore it i
s
possible to optimize charging according to battery capacity.
A
s safety features it has over voltage, over discharge, temperatur
e
detection, and a charge over timer. Also, the adaptor and th
e
charge control circuit are mounted on one chip.
NJW4120M NJW4120V
1
4
3
2
20
17
18
19
5
6
7
10
8
9
14
11
12
13
15
16
P-CHG
NFB
TX-SW
GND
PC
A
DP
LED-G
LED-R
C1
C2 CHG-SW
TL
TH
TDET
V+
VREF
VS
CS2
CS1
Q-CHG
NJW4120M
NJW4120V
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■ABSOLUTE MAXIMUM RATINGS (Ta=25°C)
PARAMETER SYMBOL MAXIMUM RATINGS UNIT
Operating Voltage V+ +15 V
C1 Pin Voltage VC1 +5 V
C2 Pin Voltage VC2 +5 V
TDET Pin Voltage VTDET +5 V
TX-SW Pin Output Current ISINK-SW 50 mA
PC Pin Output Current ISINK-PC 50 mA
LED-G Pin Output Current ISINK-G 20 mA
LED-R Pin Output Current ISINK-R 20 mA
Power Dissipation PD DMP20 :300
SSOP20 :300 mW
Operating Temperature Range Topr -20~+85 °C
Storage Temperature Range Tstg -40~+125 °C
■ELECTRICAL CHARACTERISTICS (V+=5V, Ta=25°C)
PARAMETER SYMBOL TEST CONDITION MIN. TYP. MAX. UNIT
General Characteristics
Operating Voltage VOP 2.7 – 14 V
Operating Current ICC CHG-SW: OPEN – 2 3 mA
Under Voltage Lockout Block
ON Threshold Voltage VT-ON 2.2 2.3 2.4 V
OFF Threshold Voltage VT-OFF 2.0 2.1 2.2 V
Hysteresis Voltage VHYS 100 200 300 mV
Reference Voltage Block
Reference Voltage VREF I
REF=0mA 1.228 1.24 1.253 V
Load Regulation ∆VREF I
REF=0mA~1mA – – 10 mV
Voltage Detection Block
Quick Charge Detection Voltage VQ-CHG VS: L→H VBAT
x 0.71
VBAT
x 0.73
VBAT
x 0.75 V
Re-Charge Detection Voltage VR-CHG VS: H→L VBAT
x 0.94
VBAT
x 0.95
VBAT
x 0.96 V
Over Voltage Detection Voltage VOV VS: L→H VBAT
x 1.015
VBAT
x 1.025
VBAT
x 1.035 V
Charge Control Block
Reference Voltage VREF-CV VS Pin 2.08 2.1 2.12 V
Adaptor Control Block
Reference Voltage VREF-ADP 1.228 1.24 1.253 V
VS Pin Input Bias Current IVS VS=2.1V – 50 500 nA
Battery Connected
Detection Voltage VT-TDET TDET Pin – 1.15 – V
Low Voltage Detection (2mA Charge) Block
Charge Current ICHG1 VS=1V 1 2 3 mA
Low Voltage Detection Voltage VLV VS: L→H VBAT
x 0.505
VBAT
x 0.525
VBAT
x 0.545 V
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■ELECTRICAL CHARACTERISTICS (V+=5V, Ta=25°C)
PARAMETER SYMBOL TEST CONDITION MIN. TYP. MAX. UNIT
Current Detection Block
Pre-Charge /Quick Charge Bloc
k
Voltage Gain AV1 CS1=3.8V, CS2=3.6V 11.5 12 12.5 dB
Full Charge Detection Voltage VF CS2=4.2V, VS=2.1V 8 12 16 mV
CS1 Pin Input Bias Current ICS1 CS1=4.2V – 10 500 nA
CS2 Pin Input Bias Current ICS2 CS2=4.2V – 10 500 nA
Photocoupler Out Block
Photocoupler Out
Saturation Voltage VOL-PC I
SINK=20mA – 0.2 0.5 V
PC Pin Leak Current ILEAK-PC V
+=14V – – 1
µA
TX-SW Out Block
TX-SW Out Saturation Voltage VOL-SW I
SINK=20mA – 0.2 0.5 V
TX-SW Pin Leak Current ILEAK-SW V
+=14V – – 1
µA
LED Out Block
LED-G Pin Saturation Voltage VOL-G I
SINK=10mA – 0.2 0.5 V
LED-G Pin Leak Current ILEAK-G V
+=14V – – 1
µA
LED-R Pin Saturation Voltage VOL-R I
SINK=10mA – 0.2 0.5 V
LED-R Pin Leak Current ILEAK-R V
+=14V – – 1
µA
Timer Block
OSC1 Timer Error Time ∆T1 -10 – +10 %
OSC2 Timer Error Time ∆T2
C1=C2=0.01µF external
Not including external deviation -10 – +10 %
CHG-SW Block
ON Threshold Voltage VSW-ON – – 0.25 V
OFF Threshold Voltage VSW-OFF 1 – – V
Pull-up Resistance RPULL-UP 300 500 700 kΩ
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■TYPICAL APPLICATION
Reference
Voltage 1
1.24V
Reference
Voltage 2
2.1V
VREF1
VREF2
OSC
1
OSC
2
Full
Charge
Timer
Pre-
Charge
Timer
CLK
Control
Logic
Start/Stop
Time Out
Low Voltage
Detection
Over Voltage
Detection
Re-Charge
Quick Charge
Full Charge
Detection 6dB
CVCC-ON
VREF2
12dB
Pre-Charge
Control
Quick Charge
Control
CVCC-ON
Start/Stop
Time Out
VBAT x 1.025
Charge
-ON
VBAT x 0.525
VBAT x 0.95
VBAT x 0.73
Quick/
Pre-Charge
CVCC-ON
CS1 pin 2mA
Charge
Charge
ON/OFF
Batter
y
Voltage
Detection
RP1
RP2
RQ1
RQ2
Q-CHGP-CHG
VREF
PC
NFB
CS1
RB1
RB2
VS
Rcs
CS2
TX-SW
C1
C2
GND
VREF
V+
Input
GND
CVCC-ON
VREF1
CVCC-ON
PC
A
DP
1-cell: RB1 = RB2
2-cell: RB1 = 3xRB2
A
daptor Output
RA1
RA2
LED-G
LED-R
LED-G
LED-R
RPULL-UP
V+
V+
CHG-SW
Low Temperature
Detection
High Temperature
Detection
Battery Connected
Detection
UVLO
TDET
TH
TL
Lithium Ion Battery
VREF
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■PIN CONFIGULATION
Pin No. Pin Name Function
1 P-CHG Pre-Charge Current Setting
2 NFB Current-Regulation-Loop Compensation
3 TX-SW Switch Transistor connection
4 GND GND
5 PC Photocoupler connection for the first side feedback
6 ADP Adaptor Control Voltage Setting
7 LED-G LED Output
8 LED-R LED Output
9 C1 Pre-Charge Timer, 2mA Charge Timer, LED Blinking Cycle, Delay Time Setting
10 C2 Quick Timer Setting
11 CHG-SW Charge ON/OFF Control
12 TL Batteries Thermal (High Temperature) Setting
13 TH Batteries Thermal (Low Temperature) Setting
14 TDET Battery Temperature Detection, Battery Connected Detection
15 V+ Operating Voltage
16 VREF Reference Voltage Output
17 VS Battery Voltage Detection
18 CS2 Charge Current Detection 2
19 CS1 Charge Current Detection 1
20 Q-CHG Quick Charge Current Setting
■CHARGE VOLTAGE / CURRENT for RESISTANCE SETTING
Parameter Calculation formula Examples of calculation
Adaptor Output Voltage VADP =
2A
2A1A
R
RR +x VREF-ADP (1.24V) 5.0V 10V
Charge Control Voltage VBAT =2B
2B1B
R
RR +x VREF-CV (2.1V) 4.2V 8.4V
Low Voltage Detection
Voltage VBAT x 0.525 2.21V 4.41V
Quick Charge Start Voltage VBAT x 0.73 3.07 V 6.13 V
Re-Charge Detection Voltage VBAT x 0.95 3.99 V 7.98 V
Over Voltage Detection
Voltage VBAT x 1.025 4.305 V 8.61 V
Pre-Charge Current IP-CHG = ( 2P1P
2P
RR
R
+x VREF (1.24V) / 4) / RCS
(at. RP1:232kΩ, RP2:16kΩ, RCS=0.2Ω)
100mA
Quick Charge Current IQ-CHG = ( 2Q1Q
2Q
RR
R
+x VREF (1.24V) / 4) / RCS
(at. RQ1:128kΩ, RQ2:120kΩ, RCS=0.2Ω)
750mA
Full Charge Current IF-CHG = (96mV / 8) / RCS
(at. RCS=0.2Ω) 60mA
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■TYPICAL CHARACTERISTICS
2.08
2.09
2.1
2.11
2.12
-50 -25 0 25 50 75 100 125
Ambient Temperature Ta (oC)
Reference Voltage
VREF-CV (V)
Charge Control Block Reference Voltage
v.s Temperature (V
+=5V, VS Pin)
1.23
1.235
1.24
1.245
1.25
-50 -25 0 25 50 75 100 125
Ambient Temperature
Ta (oC)
Adoptor Control Block Reference Voltage
VREF-ADP (V)
Adoptor Control Block Reference Voltage
vs. Temperature (V
+=5V)
1.23
1.235
1.24
1.245
1.25
-50 -25 0 25 50 75 100 125
Ambient Temperature
Ta (oC)
Reference Voltage VREF (V)
Reference Voltage vs. Temperature
(V+=5V, IREF=0mA)
11.4
11.6
11.8
12
12.2
12.4
12.6
-50 -25 0 25 50 75 100 125
Ambient Temperature
Ta (oC)
Pre-Charge/Quick Charge Block
Voltage Gain AV1 (dB)
Pre-Charge/Quick Charge Block Voltage Gain
vs. Temperature (V
+=5V, CS1=3.8V, CS2=3.6V)
0.2
0.3
0.4
0.5
0.6
0.7
0.8
-50 -25 0 25 50 75 100 125
Ambient Temperature
Ta (oC)
Threshold Voltage (V)
CHG-SW Block Threshold Voltage
vs. Temperature (V
+=5V)
VSW_OFF
VSW_ON
0
0.5
1
1.5
2
2.5
3
-50 -25 0 25 50 75 100 125
Ambient Temperature
Ta (oC)
Operating Current ICC (mA)
Operating Current vs. Temperature
(V+=5V, CHG-SW:OPEN)
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■TYPICAL CHARACTERISTICS
0
0.1
0.2
0.3
0.4
0.5
0 1020304050
TX-SW
PC
Saturation Voltage VOL-C NT (V)
TX-SW,PC Pin Saturation Voltage vs. Sink Current
(V+=5V, Ta=25oC)
Sink Current ISINK (mA)
0
0.1
0.2
0.3
0.4
0.5
0 5 10 15 20
Saturation Voltage VOL (V)
LED Pin Saturation Voltage vs. Sink Current
(V+=5V, Ta=25oC)
Sink Current ISINK (mA)
LED-R
LED-G
1
10
100
0.001 0.01 0.1
Oscillation Cycle OSC1, OSC2 (ms)
Oscillation Cycle vs. Capacitance
(V+=5V, Ta=25oC)
Capacitance C1, C2 (µF)
6
7
8
9
10
11
12
13
14
-50 -25 0 25 50 75 100 125
Ambient Temperature
Ta (oC)
Oscillation Cycle OSC1, OSC2 (ms)
Oscillation Cycle vs. Temperature
(V+=5V, C1=C2=0.01µF)
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■Feature Description
1. Photocoupler Feedback Unit (PC pin, CHG-SW pin, TX-SW pin)
NJW4120 feeds back voltage and current information that are required for battery charging via a photocoupler to the
primary side of the AC/DC converter, and controls AC/DC converter output. No special method is required if the
primary side of the AC/DC converter that is being controlled (whether self excited or externally excited) has circuitry
that takes into account the range of output voltage and current that is required for charge control.
It also incorporates an adaptor output mode, and extraction of any constant voltage output is possible. The following
will switch between charge control and adaptor output.
CHG-SW pin, and TDET pin battery set detection are both on: Charge control mode
Either CHG-SW pin, or TDET pin battery set detection is off: Adaptor output mode
However, if charging is prohibited due to over voltage detection, temperature detection, or the charge over timer, or
when there is 2mA of charge, the system will move to adaptor mode.
The unit that controls feedback to the photocoupler consists of the ADP voltage control, charge voltage control, and
charge current control amps. Each amp controls the photocoupler drive transistor via an OR circuit (Figure 1).
To VS pin
A
daptor output
RA1
RA2
PC
A
DP NFB
PC
CVCC-ON
CVCC-ON
CVCC-ON
To P-CHG pi n
To Q-CHG pin
To current detection
12dB amp
L
H
VREF1
(1.24V)
Pre/Quick charge switch
VREF2
(2.1V)
To AC/DC co nv erter
primary side control
ADP voltage
control
Charge Current control
Charge voltage control
TX-SW
CVCC-ON
SW transistor
Figure 1 : Photocoupler Feedback Unit and SW Transistor
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■Feature Description (Continued)
Amp control and control of the SW transistor connected to the TX-SW pin are not the same in adapter output mode
and charge control mode.
1-1. Adapter output mode (ADP pin)
In adapter output mode, each of the circuits in the control unit will be in the following state.
● ADP voltage control amp → ON
● Charge voltage control amp → OFF
● Charge current control amp → OFF
● SW transistor → OFF
To set the adapter output voltage, use the ADP pin's external resistors RA1, and RA2 and the following formula.
V
ADP =
2A
2A1A
R
RR +x VREF-ADP (1.24V)
In adapter output mode the SW transistor connected to the TX-SW pin will turn OFF, and charge to the battery will
be cut off. For this reason, take adapter output voltage from a power supply line that comes before the SW transistor.
1-2.Charge control mode
In the case of pre-charge and quick charge each of the circuits in the control unit will be in the following state.
● ADP voltage control amp → OFF
● Charge voltage control amp → ON
● Charge current control amp → ON
● SW transistor → ON
However, when there is 2mA of charge, the system will operate in adapter output mode (SW transistor → OFF).
The SW transistor turns ON, and battery charging will be performed.
Charge voltage and charge current operations are described in "2. Voltage Detection Block", and "3. Current
Detection Block".
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2. Voltage Detection Block (VS pin)
The VS pin determines charge voltage, low voltage, over voltage, and re-charge voltage. Battery voltage conditions are
constantly monitored. (Figure 2)
2-1. Charge Voltage (VS pin)
Charge voltage VBAT is set using the VS pin external
resistors RB1 and RB2 and the following equation:
VBAT =2B
2B1B
R
RR +x VREF-CV (2.1V)
Using the following settings makes it easy to support
applications for one or two cells: for one cell, RB1= RB2;
for two cells, RB1=3 x RB2.
If you use a high resistance, the VS pin's bias current will
cause incorrect values. Use as low a resistance as
possible.
2-2. Overcharge Detection Block (VS pin)
The overcharge detection block stops charging when a
high voltage is detected at the VS pin.
The overcharge detection voltage is obtained with the following equation:
VOV=VBAT × 1.025 (typ.)
When overcharge is detected, charging is prohibited and LED-R blinks. After that, charge will continue to be prohibited, even
after battery voltage drops to a normal value. Turning the power off to release UVLO, battery connection detection, or
CHG-SW switching will enable the charge sequence to restart.
2-3. Low Voltage Detection (2mA charge) Block (VS pin, CS1 pin)
The low voltage detection block detects an
over-discharged battery, or an open battery caused by
the battery protection circuit or the like. This will
determine a 2mA charge prior to pre-charging.
The low voltage detection voltage is obtained with the
following equation:
VLV=VBAT × 0.525 (typ.)
During a 2mA charge, the block monitors battery voltage
recovery while a steady 2mA current is output from the
CS1 pin. (Figure 3)
If voltage does not recover within a prescribed time, the
timer will prohibit 2mA charging. Turning the power off to
release UVLO, battery connection detection, or CHG-SW
switching will enable the charge sequence to restart.
2-4. Re-Charge Detection (VS pin)
When a fully charged battery is left for a long period of time, voltage will drop due to self-discharge. The re-charge detection
block detects a drop in voltage and re-charges the battery.
The re-charge detection voltage is obtained with the following equation.
VR-CHG=VBAT × 0.95 (typ.)
Low Voltage
Detection
12dB
CS1
RB1
RB2
VS
Rcs
CS2
To C harge
Output
Control Bloc
k
2mA Charge
Current
To Charge Current
Control Amp
2mA Charge
VBAT x 0.525
RB1
RB2
VS
To Charge
Control Block
To OR
Circuit
Charge Voltage
Control Amp
VREF2
CVCC-ON
Low Voltage
Detection
Over Voltage
Detection
Recharge
Detection
Quick Charge
Detection
Battery
Voltage
Detection
1-cell: RB1 = RB2
2-cell: RB1 = 3xRB2
VBAT x 0.95
VBAT x 0.73
VBAT x 1.025
VBAT x 0.525
Figure 2. Voltage Detection Block Configuration
Figure 3. 2mA Charging Block
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■FEATURE DESCRIPTION (CONTINUE D)
3. Current Detection Block (CS1 pin, CS2 pin)
A current detection resistor RCS is inserted between pin CS1 and pin CS2 to monitor battery charge current.
The input voltage between pin CS1 and pin CS2 is amplified by the 12dB current detection amp and fed back to the charge
current control amp. (Figure 4)
3-1. Pre-Charge Current, Quick Charge Current (P-CHG pin, Q-CHG pin)
This will switch between charging with pre-charge current or quick charge current according to the level of the battery
voltage VBAT that is input from the VS pin.
VBAT x 0.525 to VBAT x 0.73 Pre-charge control
VBAT x 0.73 to VBAT Quick charge control
Pre-charge and quick charge current values are determined by the P-CHG pin and the Q-CHG pin voltage settings.
Settings are made according to the following formulae.
Pre-Charge Current Value
IP-CHG = ( 2P1P
2P
RR
R
+x VREF (1.24V) / 4) / RCS
Quick Charge Current Value
IQ-CHG = ( 2Q1Q
2Q
RR
R
+x VREF (1.24V) / 4) / RCS
3-2. Full Charge Detection (F-CHG pin)
Charge termination is determined by a set full
charge current IF-CHG., which is determined by a
voltage setting on the F-CHG pin.
IF-CHG = (96mV/ 8) / RCS
When charging is terminated, LED-G turns on,
and the sequence moves to the re-charge
detection operation.
Figure 4. Block for Controlling Pre-Charge, Quick Charge,
and Block for Detecting Full Charge.
To OR
Circuit
Quick Charge
Detection
Full Charge
Detection 6dB
CVCC-ON
12dB
Pre-Charge
Current Setting
Quick Charge
Current Setting
Quick/
Pre-Charge
RP1
RP2
RQ1
RQ2
Q-CHG P-CHG
VREF
PC
NFB
CS1
RB1
RB2
VS
Rcs
CS2
To Charge
Output
Switch Pre/Quic
k
Charge Current
Control Block
To Charge Voltage
Control Amp
Charge Current
Control Amp
VBAT x 0.73
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■FEATURE DESCRIPTION (CONTINUE D)
4. Temperature Detection Block, Battery Connected Detection Block (TDET pin, TH pin, TL pin)
The charge temperature range is set with the TL pin (high temperature) and the TH pin (low temperature).
The threshold voltage for the temperature detection comparator is set with the external resistors RTHL, RTH, RTL. Therefore,
you can select any type of thermistor (NTC) and any charge temperature range (Figure 5).
The TL pin and the TH pin are set to go to the potential states shown below for fluctuations in TDET voltage.
VTL (high temperature) < VTDET (charge Temperature) < VTH (low temperature)
Pin voltages are obtained from the
following formulae.
TDET pin (thermistor setting)
)V24.1(REF
TTDET
T
TDET V
RR
R
V×
+
=
TH pin (low temperature setting)
)V24.1(REF
TLTHTHL
TLTH
TH V
RRR
RR
V×
++
+
=
TL pin (high temperature setting)
)V24.1(REF
TLTHTHL
TL
TL V
RRR
R
V×
++
=
Figure 5 Temperature Detection Block
When the detected temperature goes out of the range of the set values, charging stops, and LED-R and LED-G turn off.
After temperature is restored, charging recommences in line with battery voltage status.
The TDET pin is also used for the battery-connected detection feature.
The battery-connected detection feature determines that a battery is connected if TDET pin voltage is no greater than
1.15V(typ.), and commences charging.
Battery Connected
Detection
Low Temperature
Detection
High Temperature
Detection
Charge
-ON
TDET
TH
TL
Lithium Ion Battery
VREF
To CHG-SW
R
TL
R
TH
R
THL
R
TDET
R
T
To U VLO
VT-TDET=1.15V
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■FEATURE DESCRIPTION (CONTINUE D)
5. Delay Circuits (each detection block)
Each detection block has a delay circuit and extra features for preventing malfunction due to noise or excess signals.
Table 1 Delay Circuits and Extra Features.
Detection Block Delay Circuit Extra Feature
Low Voltage Malfunction
Prevention Circuit Hysteresis
CHG-SW Hysteresis
Battery Connected
Detection Hysteresis
Temperature Detection Hysteresis
Full Charge Detection –
Re-Charge Detection –
Low Voltage Detection Hysteresis
Over Voltage Detection
Delay I
Latch
Quick Charge Detection Delay II Hysteresis
The delay circuit block receives a signal from the timer circuit to fix a delay time.
For details on the relationship between the delay time and capacitors see “6. Timer Circuit Block”.
6. Timer Circuit Block (C1 pin, C2 pin)
OSC1 is used for the timer that is used for pre-charge, 2mA charge and the like. OSC2 is used for the quick charge timer.
You can change the time of the timers with external capacitors. Tables 2, 3 show the relationship between capacitance and
time.
Table 2 C1, C2 Oscillation Cycle t
Capacitance (C1, C2) Oscillation Cycle
(OSC1, OSC2)
4700pF t = 4.7ms
0.01µF t = 10ms
0.022µF t = 22ms
0.047µF t = 47ms
Table 3 Timer Time
Use capacitors the have good temperature characteristics in the OSC block.
Capacitor deviation will cause timer errors.
Block Name Parameter Calculation
Formula
Examples
2mA Charge Timer tx210 10.2s
Pre-Charge Timer tx217 22min.
LED R Blinking Cycle tx27 1.28s
Delay I tx25 0.32s
Pre-Charge Timer
Delay II tx24 0.16s
C1=0.01µF
Quick Charge Timer Quick Charge Timer tx220 2hours 55 min. C2=0.01µF
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■FEATURE DESCRIPTION (CONTINUE D)
In each charge mode if time-over occurs charging is prohibited and LED-R blinks. Turning the power off to release UVLO,
battery connection detection, or CHG-SW switching will enable the charge sequence to restart.
NJW4120 incorporates a test mode that shortens the timer block function's test time by 1/150,000.
To operate in test mode set the TH pin voltage to a value no greater than that of the TL pin. In test mode, regardless of the
external timing capacitors C1, C2, the internal timer clock frequency will operate in a range of approximately 200kHz to
300kHz. The following shows calculation values when the oscillating frequency is 250kHz (4µs cycle).
Table 4. Timer Times in Test Mode.
When the TDET pin voltage is approximately 1.2V or greater, the pre-charge / quick charge timers operate normally.
If you want to further reduce the test time, setting TDET pin voltage makes it possible to run each of the timer counters
divided in half. When the TDET pin is approximately 0.3V or less, the first half of the counter is bypassed. When the voltage
is approximately greater than 0.4V and less than 1.1V, the second half of the counter is bypassed.
Table 5. Reduced Test Time Mode
Block Name Parameter Calculation
Formula
Example
(t = Appx. 4µs)
2mA Charge Timer tx210 Appx. 4ms
Pre-Charge Timer tx217 Appx. 0.5s
LED R Blinking Cycle tx27 Appx. 0.5ms
Delay I tx25 Appx. 0.13ms
Pre-Charge Timer
Delay II tx24 Appx. 64µs
Quick Charge Timer Quick Charge Timer tx220 Appx. 4.2s
Parameter Calculation
Formula Example (t =Appx. 4µs)
Pre-Charge Timer tx28 , tx28 Appx. 1ms, Appx. 1ms
Quick Charge Timer tx29 , tx210 Appx. 2ms, Appx. 4ms
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■FEATURE DESCRIPTION (CONTINUE D)
7. Reference Voltage Block (VREF pin)
This block generates 1.24V and 4.2V reference voltages. The VREF pin outputs 1.24V. In addition to the IC internal
reference voltage, this is also used as a reference voltage for charge current setting and temperature detection setting.
It is not recommended to connect a capacitor to VREF pin.
It will take a long time to start-up of reference voltage when a capacitor is connected to VREF pin.
Therefore, it may cause malfunction of logic, charge voltage and charge current circuit.
8. Power Block, Under Voltage Lockout Circuit (UVLO) Block (V+ pin, GND pin)
An integrated Under Voltage Lockout circuit prevents IC malfunction when power is turned on or off. This circuit
incorporates a 200mV hysteresis width to prevent chattering.
As required, insert a bypass capacitor near the IC's V+ pin when there is power line noise or when wires are long.
9. LED Block (LED-R pin, LED-G pin)
The 2 LEDs can indicate charge status. (Figure 6)
The LED drive circuit is an open collector output configuration.
Therefore, it is easy to set a constant LED drive current with resistance values.
The expression for setting the current that flows through the LEDs is shown below.
ILED-G ≒ (Vcc - VF-LED - VOL-G) / RLED
or
ILED-R ≒ (Vcc - VF-LED - VOL-R) / RLED
Figure 6. LED Drive Circuit
LED-G
LED-R
Input
VF-LED
ILED
RLED
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■FLOW CHART
Start
Pre-Charge
Timer Start
YES
NO
Check
Adapter Voltage
V+>2.3V
Check
Battery Temp.
VTL<VTDET<VTH
YES
NO
YES
NO
Check
Battery Voltage
VBAT<VOV
YES
NO
Check
Voltage
VBAT>VQ-CHG
Quick Charge
Timer Start
Quick Charge Start
LED-G: OFF
LED-R: ON
TX-SW:ON
YES
NO
Time Out
YES
NO
Battery
Battery Voltage
VBAT>VQ-CHG
Time Out
NO
Check
Full Charge
IBAT<IF-CHG
YES
Charge Complete
LED-G: ON
LED-R: OFF
TX-SW:OFF
Check
Battery Voltage
VBAT<VR-CHG
YES
NO
NO
YES
Check
Battery Connection
CHG-SW Pin=GND
YES
NO
Abnormal Charging
Prohibited
LED-G: OFF
LED-R: OFF
TX-SW:OFF
LED-G: OFF
LED-R: ON
2mA Charge: ON
Abnormal Charging
Prohibited
LED-G: OFF
LED-R: ON/OFF
TX-SW:OFF
Pre-Charge Start
2mACharge: OFF
TX-SW:ON
YES
NO
Check
Battery Voltage
VBAT>VLV
YES
NO
Time Out
NO
Check
Battery Connection
VTDET<1.15V
YES
A
daptor voltage, Battery connection,
Battery Temp. and Battery voltage are
monitored during charging.
When charging is prohibited, one of the
following action resumes the charging;
Unplug and plug power supply
Remove and set batteries
Charge-SW ON/OFF
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■TIMING CHART
0V
CHG-SW
LED-R
LED-G
ON
ON
OFF ON
ON OFF
OFF
OFF
0V
TX-SW ON OFF ON ON OFF
OFF
Battery Voltage
Charge Current
Pre-
Charge
Quick
Charge
Constant
Voltage
Charge
Full
Charge
Re-
Charge
Pre-Charge Current
Full Charge Current
Quick Charge
Detecting Voltage
Quick Charge Current
Charge Control Voltage
Re-Charge Detecting Voltage
A
daptor Voltage
Charge Control Mode
A
daptor Output Mode
■The timing chart at the time of protection circuit operation
In addition to a charge timing chart, a protection circuit with a built-in IC operates according to the state and
circumference environment of a battery.
The timing chart when various protection circuits operate is as follows.
●Pre-charge time out ●Quick charge time out
Battery Voltage
0V
Charge Current
CHG-SW
LED-R
LED-G
ON
Quick charge detecting voltage
ON
OFF
OFF
A
daptor Voltage
0V
TX-SW OFF ON
OFF
Pre-charge
22min*
OFF
ON/OFF 1.28s*
Battery Voltage
0V
Charge Current
CHG-SW
LED-R
LED-G
ON
Charge Voltage
ON
OFF
OFF
A
daptor Voltage
0V
TX-SW OFF ON
OFF
Quick charge
3h*
OFF
ON/OFF
Full charge
detection
60mA*
C1=0.01
µ
F C2=0.01µF
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■The timing chart at the time of protection circuit operation (Continued)
●Over voltage battery (Return) ●Over voltage battery(Abnormalities)
Battery voltage
0V
Charge Current
CHG-SW
LED-R
LED-G
ON
Low voltage
Detecting voltage
ON
OFF
OFF
A
daptor voltage
0V
TX-SW OFF ON
OFF
Pre-charge
2m
A
Battery voltage
0V
Charge Current
CHG-SW
LED-R
LED-G
ON
ON
OFF
OFF
A
daptor voltage
0V
TX-SW OFF
OFF
Charge
STOP
2m
A
ON/OFF 1.28s*
Charge voltage
2mAcharge
10s*
C1=0.01
µ
F
2mAcharge
10s*
C1=0.01µF
Low voltage
Detecting voltage
●Over charge battery ●Abnormalities in temperature
Battery Voltage
0V
Charge Current
CHG-SW
LED-R
LED-G
ON
OFF
A
daptor Voltage
0V
TX-SW OFF
OFF
Charge STOP
Battery Voltage
0V
Charge Current
CHG-SW
LED-R
LED-G
ON
OFF
OFF
A
daptor Voltage
0V
TX-SW OFF
OFF
Charge STOP
Temperature
Detecting
ON
Over charge detecting
OFF
ON/OFF 1.28s*
C1=0.01
µ
F
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■OPERATION MATRIX
Parameter Adaptor
Mode
Quick
Charge
Pre-
Charge
2mA
Charge
Full
Charge
Temperature
Error
Over
Voltage
Error
Time OUT
LED-G OFF OFF OFF OFF ON OFF OFF OFF
LED-R OFF ON ON ON OFF OFF BLINKING BLINKING
SW-Tr. OFF ON ON OFF OFF OFF OFF OFF
Control Mode Adaptor Charge Adaptor Adaptor Adaptor Adaptor Adaptor Adaptor
Charge Current - Q-CHG P-CHG 2mA - - - -
Return Charge - - - - Re-Charge Auto Latch Latch
Timer Stop Operate Operate Operate Stop Stop Stop -
Temperature
Detecting Disregard Operate Operate Operate Operate - Operate Operate
Over Voltage
Detecting Disregard Operate Operate Operate Operate Operate - Operate
CHG-SW Stay Operate Operate Operate Operate Re-start Re-start Re-start
Battery Setting Stay Operate Operate Operate Operate Re-start Re-start Re-start
Full Charge
Detecting Disregard Operate Stop Disregard - Disregard Disregard Disregard
Disregard: Detection function is not reflected in control although it is operating.
■LED ON/OFF PATTERN
NJW4120
Parameter LED
-
R
LED
-
G
Adaptor Volta
ge
OFF OFF
Charging ON OFF
Full Charging OFF ON
Temperature Error OFF OFF
Over Voltage Detecting BLINKING OFF
Time Out BLINKING OFF
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MEMO
[CAUTION]
The specifications on this databook are only
given for information , without any guarantee
as regards either mistakes or omissions. The
application circuits in this databook are
described only to show representative usages
of the product and not intended for the
guarantee or permission of any right including
the industrial rights.