HM4066-42SIR1 [HMSEMI]
Switch Mode Li-Ion/Polymer Battery Charger;
| 型号： | HM4066-42SIR1 |
| 厂家： | 
H&M Semiconductor |
| 描述： | Switch Mode Li-Ion/Polymer Battery Charger 电池 |
| 文件： | 总19页 (文件大小：1488K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
HM4066-4.2 /8.4/ 8.34
Switch Mode Li-Ion/Polymer
Battery Charger
DESCRIPTION
FEATURES
ꢀ
Wide Input Supply Voltage Range:
The HM4066 is a constant current, constant voltage
Li-Ion battery charger controller that uses a current mode
PWM step-down (buck) switching architecture. With a
500kHz switching frequency, the HM4066 provides a
small, simple and efficient solution to fast charge one
(4.2V) or two (8.4V) cell lithium-ion batteries.
4.8V to 20V – 4.2 Version
8.9V to 20V – 8.4 Version
8.9V to 20V – 8.34 Version
ꢀ
ꢀ
ꢀ
ꢀ
ꢀ
ꢀ
ꢀ
ꢀ
500kHz Switching Frequency
End-of-Charge Current Detection Output
12 Hour Charge Termination Timer
±1% Charge Voltage Accuracy
±10% Charge Current Accuracy
Low 10µA Reverse Battery Drain Current
Automatic Battery Recharge
The HM4066 charges the battery in three phases:
conditioning, constant current, and constant voltage. An
external sense resistor sets the charge current with ±10%
accuracy. An internal resistor divider and precision
reference set the final float voltage to 4.2V per cell with ±
1% accuracy. An internal comparator detects the near
end-of-charge condition while an internal timer sets the
total charge time and terminates the charge cycle. The
HM4066 automatically re-starts the charge if the battery
voltage falls below an internal threshold, 4.05V per cell.
The HM4066 also automatically enters sleep mode when
DC supplies are removed.
Automatic Trickle Charging of Low Voltage
Batteries
ꢀ
Automatic Sleep Mode for Low Power
Consumption
ꢀ
ꢀ
ꢀ
ꢀ
ꢀ
Battery Temperature Sensing
Stable with Ceramic Output Capacitor
Support up to 3A Charge Current
8-Lead SOP Package
The HM4066 is available in the 8-lead SOP package.
RoHS Compliant and 100% Lead (Pb)-Free
Halogen-Free
APPLICATIONS
ꢀ
ꢀ
ꢀ
Small Notebook Computer
Portable DVD
Typical Operating Performance
Handheld Instruments
Efficiency vs Input voltage
Efficiency vs Input voltage
100
95
90
85
80
75
70
65
60
100
(Curves include input diode)
(Curves include input diode)
95
90
85
80
75
70
HM4066-8.4
HM4066-4.2
VBAT=3.8V
VBAT=4.0V
VBAT=7.0V
VBAT=8.0V
65
60
5
10
15
20
8
10
12
14
16
18
20
Input Voltage (V)
Input Voltage (V)
1
HM4066-4.2 /8.4/ 8.34
Typical Application Circuit
Figure 1. 1.5A Single Cell/2.0A Dual Cells Li-Ion Battery Charger
2
HM4066-4.2 /8.4/ 8.34
Block Diagram
Figure 2.
3
HM4066-4.2 /8.4/ 8.34
Pin Configurations
Package Type
Pin Configurations
SOP-8
Pin Description
PIN
SOP-8
DESCRIPTION
Current Amplifier Sense Input. A sense resistor, RSENSE, must be connected between
the SENSE and BAT pins. The maximum charge current is equal to 100mV/RSENSE.
SENSE
1
NTC (Negative Temperature Coefficient) Thermistor Input. With an external 10kꢀ NTC
thermistor to ground, this pin senses the temperature of the battery pack and stops the
charger when the temperature is out of range. To disable the temperature qualification
function, ground the NTC pin.
NTC
2
3
Compensation, Soft-Start and Shutdown Control Pin. Charging begins when the COMP
pin reaches 850mV. The recommended compensation components are a 2.2µF (or larger)
capacitor and a 0.5k series resistor (or small). A 100µA current into the compensation
capacitor also sets the soft-start slew rate. Pulling the COMP pin below 280mV will shut
down the charger.
COMP
VCC
SW
4
5
6
7
Positive Supply Voltage Input.
Power Switching Output.
IC Ground.
GND
Charge Status Output.
CHRG
BAT
Battery Sense Input. A bypass capacitor of 22µF is required to minimize ripple voltage.
When VBAT is within 250mV of VCC, the HM4066 is forced into sleep mode, dropping
ICC to 10µA.
8
4
HM4066-4.2 /8.4/ 8.34
Ordering Information
Order Number
Package Type
Marking
Operating Temperature Range
HM4066-42SIR1
HM4066-84SIR1
HM4066-834SIR1
SOP-8
HM4066-4.2
xxxx
-40 °C to +85°C
SOP-8
HM4066-8.4
xxxx
-40 °C to +85°C
-40 °C to +85°C
SOP-8
HM4066-8.34
xxxx
HM4066-□□□ □ □ □ □
Lead Free Code
1: Lead Free, Halogen Free
Packing
R: Tape & Reel
Operating temperature range
I: Industry Standard
Package Type
S:SOP
Output Voltage Option
5
HM4066-4.2 /8.4/ 8.34
Absolute Maximum Ratings
ꢁ Supply Voltage (VCC) -----------------------------------------------------------------------------------
22V
ꢁ SW ------------------------------------------------------------------------------------------------- (-1V) to VCC
ꢁ BAT, SENSE ------------------------------------------------------------------------------------- -0.3V to 14V
ꢁ CHRG ,NTC ----------------------------------------------------------------------------------------- -0.3V to 8V
ꢁ Operating Temperature Range -------------------------------------------------------------- -40°C to +85°C
ꢁ Storage Temperature Range --------------------------------------------------------------- -65°C to +125°C
ꢁ Lead Temperature (Soldering, 10sec) ------------------------------------------------------------------- 260°C
ꢁ ESD protection ---------------------------------------------------------------------------------------------
2kV
Electrical Characteristics (TA = 25°C, VCC = 10V, unless otherwise noted.)
HM4066-4.2
Symbol
Parameter
Conditions
Unit
Min. Typ. Max.
DC Characteristics
VCC
VCC Supply Voltage
4.8
20
5
V
Current Mode
1.5
1.5
10
mA
mA
µA
V
ICC
VCC Supply Current
Shutdown Mode
Sleep Mode
5
20
5V≦ VCC ≦ 20V
VBAT(FLT) Battery Regulated Float Voltage
VSNS(CHG) Constant Current Sense Voltage
VSNS(TRKL) Trickle Current Sense Voltage
4.158
90
4.2
100
4.242
110
115
22
TA =25°C
-40°C≦ TA ≦85°C
3V≦ VBAT
≦ 4V
mV
85
VBAT = 1V
8
15
mV
V
VTRKL
VUV
Trickle Charge Threshold Voltage VBAT = Rising
2.75
2.9
3.05
VCC Undervoltage Lockout
VCC = Rising
3.9
4.2
200
280
250
4.5
V
Threshold Voltage
VCC Undervoltage Lockout
Hysteresis Voltage
Manual shutdown Threshold
∆VUV
VMSD
VASD
mV
mV
mV
COMP Pin Falling
VCC - VBAT
150
450
Voltage
Automatic shutdown Threshold
Voltage
ICOMP
VCHRG
REOC
tTIMER
INTC
COMP Pin Output Current
VCOMP = 1.2V
100
20
µA
mV
%
ICHRG = 1mA
50
32
CHRG Pin Output Low Voltage
End-of-Charge Ratio
VSNS(EOC) /VSNS(CHG)
6
15
Charge time Accuracy
10
%
NTC Pin Output Current
VNTC = 0.85V
VNTC = Falling
Hysteresis
75
85
360
5
95
µA
mV
mV
V
340
380
VNTC-HOT NTC Pin Threshold Voltage (Hot)
VNTC-COLD NTC Pin Threshold Voltage (Cold)
VNTC = Rising
Hysteresis
2.35
100
2.4
100
2.45
mV
Recharge Battery Voltage Offset VBAT(FULLCHARGD) –VRECHRG, VBAT
from Full Charged Battery Voltage Falling
∆VRECHRG
150
200
1
mV
µA
ILEAK
VCHRG= 8V, Charging Stops
CHRG Pin Leakage Current
6
HM4066-4.2 /8.4/ 8.34
Electrical Characteristics (TA = 25°C, VCC = 10V, unless otherwise noted.)
HM4066-4.2
Min. Typ. Max.
55
Symbol
Parameter
Conditions
Unit
RDSON
Oscillator
fOSC
High-Side Switch On-Resistance
mꢀ
Switching Frequency
Maximum Duty Cycle
450
500
550
100
kHz
%
DC
Electrical Characteristics(TA = 25°C, VCC = 10V, unless otherwise noted.)
HM4066-8.4/8.34
Min. Typ. Max.
Symbol
Parameter
Conditions
Unit
DC Characteristics
VCC
VCC Supply Voltage
8.9
20
5
V
Current Mode
1.5
1.5
10
mA
mA
µA
ICC
VCC Supply Current
Shutdown Mode
Sleep Mode
5
20
8.34
8.257
8.316
90
8.34
8.4
100
8.423
8.484
110
115
22
9V≦ VCC
≦ 20V
0°C≦ TA ≦
85°C
VBAT(FLT) Battery Regulated Float Voltage
V
8.4
TA =25°C
6V≦ VBAT
≦ 8V
VSNS(CHG) Constant Current Sense Voltage
VSNS(TRKL) Trickle Current Sense Voltage
mV
-40°C≦ TA ≦85°C
85
VBAT = 1V
8
15
5
mV
V
VTRKL
VUV
Trickle Charge Threshold Voltage VBAT = Rising
4.7
5.3
VCC Undervoltage Lockout
VCC = Rising
7.5
500
280
250
8.5
V
Threshold Voltage
VCC Undervoltage Lockout
Hysteresis Voltage
Manual shutdown Threshold
∆VUV
VMSD
VASD
mV
mV
mV
COMP Pin Falling
VCC - VBAT
150
450
Voltage
Automatic shutdown Threshold
Voltage
ICOMP
VCHRG
REOC
tTIMER
INTC
COMP Pin Output Current
VCOMP = 1.2V
100
20
µA
mV
%
ICHRG = 1mA
50
25
CHRG Pin Output Low Voltage
End-of-Charge Ratio
VSNS(EOC) /VSNS(CHG)
5
15
Charge time Accuracy
10
%
NTC Pin Output Current
VNTC = 0.85V
VNTC = Falling
Hysteresis
75
85
360
5
95
µA
mV
mV
V
340
380
VNTC-HOT NTC Pin Threshold Voltage (Hot)
VNTC-COLD NTC Pin Threshold Voltage (Cold)
VNTC = Rising
Hysteresis
2.35
200
2.4
100
2.45
mV
Recharge Battery Voltage Offset VBAT(FULLCHARGD) –VRECHRG, VBAT
from Full Charged Battery Voltage Falling
∆VRECHRG
300
400
1
mV
ILEAK
VCHRG= 8V, Charging Stops
µA
CHRG Pin Leakage Current
RDSON
High-Side Switch On-Resistance
55
mꢀ
7
HM4066-4.2 /8.4/ 8.34
Electrical Characteristics (TA = 25°C, VCC = 10V, unless otherwise noted.)
HM4066-8.4/8.34
Min. Typ. Max.
Symbol
Parameter
Conditions
Unit
Oscillator
fOSC
Switching Frequency
Maximum Duty Cycle
450
500
550
100
kHz
%
DC
8
HM4066-4.2 /8.4/ 8.34
Typical Operating Characteristics
Supply Current vs Vcc
SupplyCurrent vsTemperature
4.0
2.0
(Current mode)
3.5
3.0
2.5
2.0
1.5
1.0
0.5
1.8
1.6
1.4
1.2
1.0
5
10
15
20
-40
-20
0
20
40
60
80
100
120
TEMPERATURE(°C)
Vcc (V)
Oscillator FrequencyvsTemperature
Oscillator Frequency vs Vcc
540
540
520
500
480
460
520
500
480
460
5
10
15
20
-40
-20
0
20
40
60
80
100
120
Vcc (V)
TEMPERATURE(°C)
Undervoltage Lockout Thresholdvs Temperature
9
8
7
6
5
4
3
HM4066-4.2
HM4066-8.4
-40
-20
0
20
40
60
80
100
120
TEMPERATURE(°C)
9
HM4066-4.2 /8.4/ 8.34
Typical Operating Characteristics (continued)
CHRG Pin Output Low Voltage vs Vcc
CHRG Pin Output Low Voltage vs Temperature
25
30
Iload=1mA
Iload=1mA
20
25
20
15
10
15
10
5
5
10
15
20
-40
-20
0
20
40
60
80
100
120
TEMPERATURE(°C)
Vcc (V)
Recharge Voltage Offset from Full Charged
Voltage vs Vcc
Recharge Voltage Offset from Full Charged
Voltage vs Vcc
160
320
HM4066-8.4
HM4066-4.2
315
310
305
300
295
290
285
280
155
150
145
140
5
10
15
20
5
10
15
20
Vcc (V)
Vcc (V)
COMP Pin Output Current vs Vcc
Current Mode Sense Voltage vs Vcc
104
102
100
98
102
100
98
VCOMP=1.2V
VBAT=4.0V
HM4066-4.2
96
96
94
94
5
10
15
20
5
10
15
20
Vcc (V)
Vcc (V)
10
HM4066-4.2 /8.4/ 8.34
Typical Operating Characteristics (continued)
COMPPinOutput Current vsTemperature
Current Mode Sense Voltage vs Vcc
120
106
VCOMP=1.2V
118
VBAT=8V
HM4066-8.4
116
114
112
110
108
106
104
102
104
102
100
98
-40
-20
0
20
40
60
80
100
120
5
10
15
20
Vcc (V)
TEMPERATURE(°C)
TrickleChargeVoltagevsTemperature
Current ModeSenseVoltagevsTemperature
3.00
2.95
2.90
2.85
2.80
104
103
102
101
100
99
HM4066-4.2
98
97
96
-40
-20
0
20
40
60
80
100
120
-40
-20
0
20
40
60
80
100
120
TEMPERATURE(°C)
TEMPERATURE(°C)
Trickle Charge Voltage vs Vcc
Trickle Charge Voltage vs Vcc
5.2
3.0
HM4066-4.2
HM4066-8.4
5.1
5.0
4.9
4.8
2.9
2.8
5
10
15
20
5
10
15
20
Vcc (V)
Vcc (V)
11
HM4066-4.2 /8.4/ 8.34
Typical Operating Characteristics (continued)
TrickleChargeVoltagevsTemperature
TrickleChargeSenseVoltagevsTemperature
5.2
20
HM4066-8.4
VBAT=2.5V
HM4066-4.2
18
5.1
16
14
12
10
8
5.0
4.9
4.8
-40
-20
0
20
40
60
80
100
120
-40
-20
0
20
40
60
80
100
120
TEMPERATURE(°C)
TEMPERATURE(°C)
TrickleChargeSenseVoltagevsTemperature
Trickle Charge Sense Voltage vs Vcc
20
18
16
14
12
10
8
25
VBAT=4V
HM4066-8.4
VBAT=2.5V
HM4066-4.2V
20
15
10
5
-40
-20
0
20
40
60
80
100
120
5
10
15
20
Vcc (V)
TEMPERATURE(°C)
End-of-ChargeRatiovsTemperature
Trickle Charge Sense Voltage vs Vcc
22
25
HM4066-8.4
VBAT=4V
HM4066-8.4V
20
18
16
14
12
20
15
10
5
-40
-20
0
20
40
60
80
100
120
5
10
15
20
TEMPERATURE(°C)
Vcc (V)
12
HM4066-4.2 /8.4/ 8.34
Typical Operating Characteristics (continued)
NTCPinOutput Current vsTemperature
End-of-Charge Ratio vs Vcc
94
22
VNTC=0V
92
HM4066-8.4
20
90
88
86
84
82
80
18
16
14
-40
-20
0
20
40
60
80
100
120
5
10
15
20
Vcc (V)
TEMPERATURE(°C)
NTC Pin Output Current vs Vcc
88
86
84
VNTC=0V
5
10
15
20
Vcc (V)
13
HM4066-4.2 /8.4/ 8.34
Application Information
Figure 3. Operational Flow Chart
14
HM4066-4.2 /8.4/ 8.34
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 of 4.05V per cell.
OPERATION
The HM4066 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 (RSENSE
across the SENSE and BAT pins. The final battery float
voltage is internally set to 4.2V per cell. For batteries like
lithium-ion that require accurate final float voltage, the
internal 2.4V reference, voltage amplifier and the resistor
divider provide regulation with ±1% accuracy.
When the input voltage is present, the charger can be shut
down (ICC =1.5mA) by pulling the COMP pin low. When
the input voltage is not present, the charger goes into
sleep mode, dropping ICC to 10µA. This will greatly
reduce the current drain on the battery and increase the
standby time.
)
A 10kꢀ NTC (negative temperature coefficient)
thermistor can be connected from the NTC pin to ground
for battery temperature qualification. The charge cycle is
suspended when the temperature is outside of the 0°C to
50°C window.
APPLICATIONS INFORMATION
Undervoltage Lockout (UVLO)
An undervoltage lockout circuit monitors the input
voltage and keeps the charger off until VCC rises above
the UVLO threshold (4.2V for the 4.2 version, 7.5V for
the 8.4 version) and at least 250mV above the battery
voltage. To prevent oscillation around the threshold
voltage, the UVLO circuit has 200mV per cell of built-in
hysteresis. When specifying minimum input voltage
requirements, the voltage drop across the input blocking
diode must be added to the minimum VCC supply voltage
specification.
Figure 4.Typical Charge Profile
A charge cycle begins when the voltage at the VCC pin
rises above the UVLO level and is 250mV or more
greater than the battery voltage. At the beginning of the
charge cycle, if the battery voltage is less than the trickle
charge threshold, 2.9V for the 4.2 version and 5V for the
8.4 version, the charger goes into trickle charge mode.
The trickle charge current is internally set to 15% of the
full-scale current. If the battery voltage stays low for 1
hour, the battery is considered faulty and the charge cycle
is terminated.
Trickle Charge and Defective Battery Detection
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 15% of the full-scale current. If the low-battery
voltage persists for 1 hour, the battery is considered
defective, the charge cycle is terminated and the
pin is forced high impedance.
CHRG
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 RSENSE
and an internal 100mV reference;
V
15mV
SNS(TRKL)
I
=
=
TRKL
R
R
SENSE
SENSE
V
100mV
SNS(CHG)
Shutdown
I
=
=
ꢀ
CHG
R
R
The HM4066 can be shut down by pulling the COMP
pin to ground which turning off the P-channel MOSFET.
When the COMP pin is released, the internal timer is
reset and a new charge cycle starts. In shutdown, the
SENSE
SENSE
When the battery voltage approaches the programmed
float voltage, the charge current will start to decrease.
When the current drops to 15% (4.2 version) or 15% (8.4
version) of the full-scale charge current, an internal
comparator turns off the internal pull-down N-channel
output of the
pin is high impedance and the
CHRG
quiescent current remains at 1.5mA. Removing the input
power supply will put the charger into sleep mode. If the
voltage at the VCC pin drops below (VBAT + 250mV) or
below the UVLO level, the HM4066 goes into a low
current (ICC = 10µA) sleep mode, reducing the battery
drain current.
MOSFET at the
pin, and to indicate a near
CHRG
end-of-charge condition.
An internal 12 hour timer determines the total charge
time. After a time out occurs, the charge cycle is
terminated and the CHRG pin is forced high impedance.
15
HM4066-4.2 /8.4/ 8.34
CHRG Status Output Pin
the battery temperature is within an acceptable range.
Connect a 10kꢀ thermistor from the NTC pin to ground.
If the temperature rises to 50°C, the resistance of the
NTC will be approximately 4.2kꢀ. With the 85µA
pull-up current source, the Hot temperature voltage
threshold is 360mV. For Cold temperature, the voltage
threshold is set at 2.4V which is equal to 0°C (RNTC
28kꢀ) with 85µA of pull-up current. If the temperature is
outside the window, turning off P-channel MOSFET and
When a charge cycle starts, the
pin is pulled to
CHRG
ground by an internal N-channel MOSFET which is
capable of driving an LED. When the charge current
drops below the End-of-Charge threshold, the N-channel
MOSFET turns off is connected to the
until the timer ends the charge cycle, or the charger is in
manual shutdown or sleep mode.
pin and
CHRG
Table1:
Status Pin Summary
CHRG
CHARGE STATE
the timer frozen while the output status at the
CHRG
pin remains the same. The charge cycle begins or
resumes once the temperature is within the acceptable
range. Short the NTC pin to ground to disable the
temperature qualification feature. However the user may
modify these thresholds by adding two external resistor.
See figure 6.
Pin
CHRG
Trickle Charge in Process
Strong On
Strong On
Strong On
Constant Current Charge in Process
Constant Voltage Charge in Process
Strong On
(remains the
same)
Charge Suspend (Temperature)
Timer Fault
Hi-Z
Hi-Z
Hi-Z
Hi-Z
Sleep / Shutdown
End of Charge
Battery Disconnected
After a time out occurs (charge cycle ends), the pin will
become high impedance.
Figure 5. Temperature Sensing Configuration
Stability
Both the current loop and the voltage loop share a
common, high impedance, compensation node (COMP
pin). A series capacitor and resistor on this pin
compensates both loops. The resistor is included to
provide a zero in the loop response and boost the phase
margin. The compensation capacitor also provides a
soft-start function for the charger. Upon start-up, then
ramp at a rate set by the internal 100µA pullup current
source and the external capacitor. Battery charge current
starts ramping up when the COMP pin voltage reaches
0.85V and full current is achieved with the COMP pin at
1.3V. With a 2.2µF capacitor, time to reach full charge
current is about 10ms. Capacitance can be increased if a
longer start-up time is needed.
Figure 6. Temperature Sensing Thresholds
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.
Automatic Battery Recharge
After the 12 hour charge cycle is completed and both the
battery and the input power supply (wall adapter) are still
connected, a new charge cycle will begin if the battery
voltage drops below 4.05V per cell due to self-discharge
or external loading. This will keep the battery capacity at
more than 80% at all times without manually restarting
the charge cycle.
Battery Temperature Detection
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
16
HM4066-4.2 /8.4/ 8.34
TJ = 50°C + (0.099W)(65°C /W) = 56.5°C
The selection of output capacitor COUT is primarily
determined by the ESR required to minimize ripple
voltage and load step transients. The output ripple ∆VOUT
is approximately bounded by:
CIN is chosen for an RMS current rating of about 0.8A at
85°C. The output capacitor is chosen for an ESR similar
to the battery impedance of about 100mꢀ The ripple
voltage on the BAT pin is:
1
ꢁV ≤ ꢁI ESR +
∆I
(
ESR
)
OUT
L
L
(
max
2
)
8f
C
OUT
V
=
=
OSC
OUT(RIPPLE)
Since ∆IL increases with input voltage, the output ripple
is highest at maximum input voltage. Typically, 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
0.2ꢀ and the battery impedance is raised to 4ꢀ with a
bead or inductor, only 5% of the current ripple will flow
in the battery.
(
0.94A)(0.1Ω)
= 47mV
2
For dual cells charge,
VIN = 5V to 20V, VBAT = 8V nominal, IBAT =3A,
fOSC = 500kHz, IEOC=0.45A,
100mV
R
=
= 33mꢀ
SENSE
3A
Choose the inductor for about 50% ripple current at the
maximum VIN:
8V
500kHz)(0.5)(3A
8V
L =
1 −
= 6.4µH
(
)
20V
Design Example
Selecting a standard value of 6.8ꢁH results in a
maximum ripple current of :
As a design example, take a charger with the following
specifications:
For single cell charge, VIN = 5V to 20V, VBAT = 4V
nominal, IBAT =1.5A, fOSC = 500kHz, see Figure 1.
8V
8V
∆I
=
1 −
= 1.441A
≈ 3.720A
L
(
500kHz)(6.8
µ
H
)
20V
First, calculate the SENSE resistor :
100mV
∆I
1.441A
2
L
2
ILPK = I
+
= 3A +
R
=
= 68mꢀ
CHG
SENSE
1.5A
The maximum power dissipation with VIN = 9V and VBAT
= 8V at 50°C ambient temperature is:
Choose the inductor for about 65% ripple current at the
maximum VIN:
2
4V
500kHz)(0.65)(1.5A
4V
(
3A) (55mΩ)(8V
)
L =
1 −
= 6.56
µ
H
P
=
= 0.44W
(
)
20V
D
9V
TJ = 50°C + (0.44W)(65°C /W) = 78.6°C
Selecting a standard value of 6.8ꢁH results in a
maximum ripple current of :
∆I
(
ESR
)
L
(
max
2
)
V
=
=
OUT(RIPPLE)
4V
4V
∆I
=
1 −
= 941.2mA
(
1.441A)(0.1Ω
)
L
(
500kHz)(6.8
µ
H
)
20V
= 72mV
2
∆I
941.2mA
2
L
The Schottky diode D2 shown in Figure 1 conducts
current when the pass transistor is off. In a low duty
cycle case, the current rating should be the same or
higher than the charge current. Also it should withstand
reverse voltage as high as VIN.
ILPK = I
+
= 1.5A +
≈ 1.975A
CHG
2
Next, the P-channel MOSFET. For example, a SOP-8
package with RDS(ON) = 42mꢀ (nom), 55mꢀ (max) offers
a small solution. The maximum power dissipation with
VIN = 5V and VBAT = 4V at 50°C ambient temperature is:
Board Layout Suggestions
2
(
1.5A) (55mΩ)(4V
)
When laying out the printed circuit board, the following
considerations should be taken to ensure proper operation
of the HM4066.
P
=
= 0.099W
D
5V
17
HM4066-4.2 /8.4/ 8.34
To minimize radiation, the catch diode and the input
bypass capacitor traces should be kept as short as
possible. The positive side of the input capacitor should
be close to the source of the P-channel MOSFET; it
provides the AC current to the pass transistor. The
connection between the catch diode and the pass
transistor should also be kept as short as possible. The
SENSE and BAT pins should be connected directly to the
sense resistor (Kelvin sensing) for best charge current
accuracy. Avoid routing the NTC PC board trace near the
SW switch to minimize coupling switching noise into the
NTC pin.
The compensation capacitor connected at the COMP pin
should return to the ground pin of the IC or as close to it
as possible. This will prevent ground noise from
disrupting the loop stability. The ground pin also works
as a heat sink, therefore use a generous amount of copper
around the ground pin. This is especially important for
high VCC.
18
HM4066-4.2 /8.4/ 8.34
Packaging Information
SOP-8
MILLIMETERS
INCHES
SYMBOLS
MIN.
1.35
0.05
4.80
3.70
5.80
0.40
0.31
Normal
MAX.
1.75
0.25
5.00
4.00
6.20
1.27
0.51
MIN.
0.053
0.002
0.189
0.146
0.228
0.016
0.012
Normal
MAX.
0.069
0.010
0.197
0.157
0.244
0.050
0.020
A
A1
D
E1
E
-
-
-
-
0.193
0.154
0.236
-
4.90
3.90
6.00
L
-
b
-
-
e
1.27 REF
0.050 REF
19
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