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FFeeaattuurrees
Input Supply Range: 4.7V ～ 6V
High Efficiency Current Mode PWM Controller
End - Charge - Current Detection Output
Constant Switching Frequency for Minimum
±1% Charge Voltage Accuracy
Automatic Battery Recharge
Automatic Shutdown When Input Supply is
Automatic Trickle Charging of Low Voltage
Battery Temperature Sensing
Stable with Ceramic Output Capacitor
8-Lead SOP Package
AApppplliiccaattiioonn
Charging Docks
Handheld Instruments
Portable Computers
HX1001
SSttaannddaalloonnee LLii--LLoonn SSwwiittcchh MMooddee BBaatttteerryy CChhaarrggeerr
s
Noise
Removed
Batteries
DDeessccrriippttiioon
The HX6202 is a complete battery charger
controller for one (4.22V) cell lithium-ion battery.
The HX6202 provides a small, simple and efficient
solution to fast charge Li-ion battery. An external
sense resistor sets the charge current with high
accuracy. An internal resistor divider and precision
reference set the final float voltage to 4.22V per
cell with ±1% accuracy.
When the input supply is removed, the HX6202
automatically enters a low current sleep mode,
dropping the battery drain current to 4µA. After the
charge cycle ends, if the battery voltage drops
below 4.05V per cell, a new charge cycle will
automatically begin.
The HX6202 is available in the 8-lead SOP
Package.
n
HX6202
TTyyppiiccaall AApppplliiccaattiioonn CCiirrccuuiitt
*The charge current can be set by I
*This application circuit is for MID.
m
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= 0.17V/R3.
BAT
1
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HHXX6622002
2
DC+
Schottky
Diode
C1
10uF
R1
2k
R2
10k
1
7
8
VIN
EN
CHRG
TS FB
GND
6
PROG
SW
5
3
4
2
Schottky
L1 4.7uH
*This application circuit is for backup source specially.
PPiinn AAssssiiggnnmmeenntt aanndd DDeessccrriippttiioonn
PIN NAME DESCRIPTION
1 EN
Diode
C4
10uF
Q1
R3
C2
20uF
R4
100k
R5
22k
Q2
C3
10uF
R6
10k
ON/OFF Control(High Enable)
VOUT
Battery
DC+
2 FB
Feedback
3 PROG Charge Current Program
4 SW
5 GND
6 VIN
7 CHRG Open-Drain Charge Status for Output
Switch Output
Ground
Input
8 TS Temperature Sense
s
AAbbssoolluuttee MMaaxxiimmuumm RRaattiinnggs
(Note 1)
VIN, CHRG, SW, PROG Voltage................................................................................. -0.3V ～ 6.5V
SW Pin Current ......................................................................................................................... 3.8A
Operating Temperature Range (Note 2)..................................................................... -40℃ ～ +85℃
Maximum Junction Temperature ........................................................................................... +150℃
Storage Temperature Range …………………………………………….....................-65℃ ～ +125℃
Lead Temperature (Soldering, 10 sec)....................................................................................+265℃
Note 1: Stresses listed as the above “Absolute Maximum Ratings” may cause permanent damage to the device.
Exposure to absolute maximum rating conditions for extended periods may remain possibility to affect device reliability.
Note 2: The HX6202 is guaranteed to meet performance specifications from 0C to 70C. Specifications over the –40C
to 85C operating temperature range are assured by design, characterization and correlation with statistical process
controls
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HHXX6622002
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EElleeccttrriiccaall CChhaarraacctteerriissttiiccss
Operating Conditions: TA=25 , ℃ VIN=5V, unless otherwise specified.
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
VIN Input Supply Voltage
4.7 5.0 6 V
Shutdown Mode 19 μA
IQ Input Supply Current
Sleep Mode 4 μA
V
ASD
f
OSC
DC Maximum Duty Cycle
Automatic Shutdown
Threshold Voltage
Switching Frequency I
VIN – V
BAT
150 mV
BAT
= 1A 1 MHz
100 %
Battery Voltage Regulation Constant-Current Charge
V
FLOAT
V
SNS(CHG)
Battery Regulated Float
Voltage
Constant Current Sense
Voltage
0 ≤TA≤85 , I℃℃
3V ≤ V
≤ 4V 170 mV
BAT
= 1.2A 4.17 4.22 4.26 V
OUT
Trickle Charge
Trickle Current Sense
V
SNS(TRIKL)
Voltage
Trickle Charge Threshold
V
TRIKL
Voltage
Battery Recharge Threshold
Recharge Battery
ΔV
RECHRG
Voltage Offset from Full
Charged Battery Voltage
TS Pin
TS Pin Threshold
V
V
TS- HOT
TS- COLD
Voltage (Hot)
TS Pin Threshold
Voltage (Cold)
ITS TS Pin Output Current V
V
= 0V 10 mV
BAT
V
Rising 2.9 V
BAT
V
BAT(FULLCHARGED)
V
Falling
BAT
Falling
V
TS
– V
Hysteresis
Rising
V
NTC
Hysteresis
= 0.85V 82 μA
TS
RECHRG
,
170 mV
0.54 V
2.36 V
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HHXX6622002
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TTyyppiiccaall PPeerrffoorrmmaannccee CChhaarraacctteerriissttiiccss
Operating Conditions: TA = 25 ,℃ R3 = 0.33||0.33Ω, unless otherwise specified.
Efficiency vs Char ge Cur rent
=5V)
(V
IN
95%
90%
85%
80%
Eff iciency
75%
70%
65%
200 350 500 650 800 950 1100
I
(mA)
BAT
95%
90%
85%
80%
Eff iciency
75%
70%
65%
Efficiency vs Batter y Voltage
(V
3 3.2 3.4 3.6 3.8 4 4.2
V
IN
BAT
=5V)
(V)
Charge Cur r ent vs Battery Voltage
(V
=5V)
IN
1.2
1
0.8
(A)
0.6
BAT
I
0.4
0.2
0
2 2.4 2.8 3.2 3.6 4 4.4
V
(V)
BAT
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HHXX6622002
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PPiinn FFuunnccttiioonnss
EN (Pin 1): ON/OFF Control (High Enable).
FB (Pin 2): Feedback Pin. Receive the feedback voltage from an external resistor across the output.
PROG (Pin 3): Charge Current Program. The output current is set by an external resistor according to
the following formula: I
SW (Pin 4): Charge Current Output. It provides charge current to the battery and regulates the final float
voltage to 4.22V.
GND (Pin 5): IC Ground.
VIN (Pin 6): Positive Supply Voltage Input. VIN can range from 4.7V to 6V. A 10µF low ESR capacitor is
required at the source pins of the power P-channel MOSFET.
CHRG (Pin 7): When the charge current drops below the End-of-Charge threshold for more than 120µs,
the N-channel MOSFET turns off and a weak current source is connected from the CHRG pin to GND.
When the input supply is removed, the weak current source is turned off and the CHRG pin becomes
high impedance.
TS (Pin 8): TS Thermistor Input. With an external 10kΩ negative temperature coefficient thermistor to
ground, this pin senses the temperature of the battery pack and stops the charger when the
temperature is out of range. When the voltage at this pin drops below 540mV at hot temperature or rises
above 2.36V at cold temperature, charging is suspended and the internal timer stops. The CHRG pin
output is not affected during this hold state. To disable the temperature qualification function, ground the
BAT
= 0.17V/R3.
TS pin.
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HHXX6622002
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BBlloocckk DDiiaaggrraamm
M2
VIN
6
M1
I
SLOP
I
L
CLK:
-
C
+
PWM
SRQ
DRIVER
DRIVER
C
CA
VA
EOC
16mV
+
+
-
170mV
+
-
+
-
+
4.22V
M4
4
SW
M5
3
PROG
FB
2
EN
CHRG
+
M3
1
EOC
RQ
C/10
STOP
LOGIC
TEMP
7
Q4
Q5
C
C
C
LB
RQ
COLD
-
2.9V
+
-
+
-
4.05V
2.36V
82µA
VIN
8
TS
-
C
HDT
+
5
GND
540mV
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HHXX6622002
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AApppplliiccaattiioonn IInnffoorrmmaattiioon
Functional Description
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Figure 1: Operation Flow Chart
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Operation
The HX6202 is a constant current, constant voltage Li-Ion battery charger controller that uses a current
mode PWM step-down (buck) switching architecture. The charge current is set by an external sense
resistor (R3) across the PROG and FB pins. The final battery float voltage is internally set to 4.22V. For
batteries like lithium-ion that require accurate final float voltage, the internal reference, voltage amplifier
and the resistor divider provide regulation with high accuracy.
At the beginning of the charge cycle, if the battery voltage is less than the trickle charge threshold, the
charger goes into trickle charge mode. The trickle charge current is internally set to 8% of the full-scale
current.
When the battery voltage exceeds the trickle charge threshold, the charger goes into the full-scale
constant current charge mode. In constant current mode, the charge current is set by the external sense
resistor R3 and an internal 170mV reference: I
When the battery voltage approaches the programmed float voltage, the charge current will start to
decrease. When the current drops to 8% of the full-scale charge current, an internal comparator turns
off the internal pull-down N-channel MOSFET at the CHRG pin, and connects a weak current source to
ground to indicate a end-of-charge condition and then the charge cycle is terminated and the CHRG pin
is forced high impedance.
= 0.17V/R3.
BAT
HHXX6622002
2
To restart the charge cycle, remove and reapply the input voltage or momentarily shut the charger down.
Also, a new charge cycle will begin if the battery voltage drops below the recharge threshold voltage.
When the input voltage is present, the charger can be shut down. When the input voltage is not present,
the charger goes into sleep mode. This will greatly reduce the current drain on the battery and increase
the standby time.
A 10kΩ TS (negative temperature coefficient) thermistor can be connected from the TS pin to ground for
battery temperature qualification.
Qualification and Precharge
The HX6202 suspends charge if the battery temperature is outside the V
charge until the battery temperature is within the allowed range. The HX6202 also checks the battery
voltage. If the battery voltage is below the precharge threshold V
condition the battery. The conditioning charge rate I
current. See Figure 2 for a typical charge-profile.
(PRECHG)
is set at approximately 8% of the regulation
(min)
to V
TS1
, the HX6202 uses precharge to
range and suspends
TS2
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Figure 2: Typical Charge Profile
HHXX6622002
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Charge Termination Recharge
The HX6202 monitors the charging current during the voltage-regulation phase. The HX6202 declares a
done condition and terminates charge when the current drops to the charge termination threshold
new charge cycle begins when the battery voltage falls below 4.05V.
Battery Temperature Monitoring
A negative temperature coefficient (NTC) thermistor located close to the battery pack can be used to
monitor battery temperature and will not allow charging unless the battery temperature is within an
acceptable range.
Connect a 10kΩ thermistor from the TS pin to ground. With the 82µA pull-up current source, the Hot
temperature voltage threshold is 540mV. For Cold temperature, the voltage threshold is set at 2.36V
with 82µA of pull-up current. The charge cycle begins or resumes once the temperature is within the
acceptable range.
Charge Status Indication
The HX6202 reports the status of the charge on the CHRG pin. The following Table 1 summarized the
operation of the CHRG pin. The CHRG pin can be used to drive a chip LED.
Table 1: Pin status summary
A
.
Battery conditioning and charging Low
Charge complete(done) Hi-Z
Temperature fault or sleep mode Hi-Z
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CONDITION CHRG PIN
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Trickle Charge
At the beginning of a charge cycle, if the battery voltage is below the trickle charge threshold, the
charger goes into trickle charge mode with the charge current reduced to 8% of the full-scale current.
Shutdown
The HX6202 can be shut down by pulling the EN pin to ground. In shutdown, the output of the CHRG
pin is high impedance and the quiescent current remains at 19μA.
Input and Output Capacitors
Since the input capacitor is assumed to absorb all input switching ripple current in the converter, it must
have an adequate ripple current rating. Worst-case RMS ripple current is approximately one-half of
output charge current. Actual capacitance value is not critical. Solid tantalum capacitors have a high
ripple current rating in a relatively small surface mount package, but caution must be used when
tantalum capacitors are used for input bypass. High input surge currents can be created when the
adapter is hot-plugged to the charger and solid tantalum capacitors have a known failure mechanism
when subjected to very high turn-on surge currents. Selecting the highest possible voltage rating on the
capacitor will minimize problems. Consult with the manufacturer before use. The selection of output
capacitor C
transients. The output ripple ΔV
is primarily determined by the ESR required to minimize ripple voltage and load step
OUT
is approximately bounded by:
OUT
HHXX6622002
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Since ΔI
once the ESR requirement is satisfied, the capacitance is adequate for filtering and has the necessary
RMS current rating.
Switching ripple current splits between the battery and the output capacitor depending on the ESR of
the output capacitor and the battery impedance. EMI considerations usually make it desirable to
minimize ripple current in the battery leads. Ferrite beads or an inductor may be added to increase
battery impedance at the 500kHz switching frequency. If the ESR of the output capacitor is 0.2Ω and the
battery impedance is raised to 4Ω with a bead or inductor, only 5% of the current ripple will flow in the
battery.
increases with input voltage, the output ripple is highest at maximum input voltage. Typically,
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HHXX6622002
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PPaacckkaaggiinngg IInnffoorrmmaattiioonn
SOP-8L Package Outline Dimension
Symbol
A 1.350 1.750 0.053 0.069
A1 0.100 0.250 0.004 0.010
A2 1.350 1.550 0.053 0.061
b 0.330 0.510 0.013 0.020
c 0.170 0.250 0.006 0.010
D 4.700 5.100 0.185 0.200
E 3.800 4.000 0.150 0.157
E1 5.800 6.200 0.228 0.244
e 1.270(BSC) 0.050(BSC)
L 0.400 1.270 0.016 0.050
θ 0° 8° 0° 8°
Dimensions In Millimeters Dimensions In Inches
Min Max Min Max
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Subject changes without notice.
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Information furnished by Hexin Semiconductor is believed to be accurate and reliable. However, no responsibility is assumed for its use.
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