ACE ACE4054C 500ma/1.5a standalone linear li-ion battery charge Datasheet

ACE4054C
500mA/1.5A Standalone Linear Li-Ion Battery Charge
Description
The ACE4054C is a single cell, fully integrated constant current (CC)/ constant voltage (CV) Li-ion
battery charger. Its compact package with minimum external components requirement makes the
ACE4054C ideal for portable applications.
No external sense resistor or blocking diode is necessary for the ACE4054C. Build-in thermal feedback
mechanism regulates the charge current to control the die temperature during high power operation or at
elevated ambient temperature.
The ACE4054C has a pre-charge function for trickle charging deeply discharged batteries. The fast
charge current can be programmed by an external resistor. CV regulation mode is automatically enabled
once the battery’s charging curve reaches the constant voltage portion. The output current then decays
and is finally terminated once the charge current drops to 1/10th of the programmed value. The
ACE4054C keeps monitoring the battery voltage and enables a new charge cycle once the voltage drops
by 150mV below the CV value.
Power supply state is constantly monitored and the battery drain current is reduced to minimum value
automatically when the ACE4054C senses a lack of input power. In its shutdown mode, the ACE4054C
can reduce the supply current to less than 25μA. A status pin outputs a logic HIGH/LOW to indicate the
charging status and the presence of power supply.
Other features include charge current monitor, under-voltage lockout.
Features
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Standalone Capability with no Requirement of External MOSFET, Sense Resistor or Blocking Diode
Complete Linear Charger in Compact Package for Single Cell Lithium-Ion Batteries
Programmable Pre-charge, Fast Charge and Termination Current
Constant-Current/Constant-Voltage Operation with Thermal Regulation to Maximize Charge Rate
Without Risk of Overheating
Charges Single Cell Li-Ion Batteries Directly from USB Port
Preset 4.2V Charge Voltage with ±1% Accuracy
Automatic Recharge
Charge Status Output Pin
C/10 Charge Termination
25μA Supply Current in Shutdown
2.9V Trickle Charge Threshold
Soft-Start Limits Inrush Current
Application
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Cellular Telephones,PDAs,MP3 Players
Charging Docks and Cradles
Bluetooth Applications
VER 1.2
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ACE4054C
500mA/1.5A Standalone Linear Li-Ion Battery Charge
Absolute Maximum Ratings
Parameter
Max
Unit
VCC
-0.3 ~6.5
V
PROG
-0.3 ~ VCC+0.3
V
BAT
-0.3 ~ 5
V
-0.3 ~ 6.5
V
CHRG
BAT Short-Circuit Duration
Continuous
PROG Pin Current
2
mA
Maximum Junction Temperature
125
℃
Operating Ambient Temperature Range
-40 ~ 85
℃
Storage Temperature Range
-40 ~ 125
℃
Note: Exceed these limits to damage to the device.
Exposure to absolute maximum rating conditions may affect device reliability.
Packaging Type
SOT-23-6
6
1
5
2
ESOP-8
SOT-23-6 ESOP-8 Description
4
3
1
8
1
7
CHRG
2
7
2
3
GND
3
6
3
5
BAT
4
5
4
4
VCC
5
6
STDBY
6
2
PROG
1.8
NC
Pin Description
CHRG: Open-Drain Charge Status Output. The CHRG pin outputs low when the battery is charging.
STDBY: Open-Drain Charge Status Output. The STDBY pin outputs low when the battery is full.
GND: Ground.
BAT: Charge Current Output. This pin provides charge current to the battery and regulates the final float
voltage to 4.2V which is set by an internal precision resistor divider.
VCC: Positive Input Supply. Needs to be bypassed with at least a 1μF capacitor. When input voltage
drops to within 30mV of the BAT pin voltage, the ACE4054C switches to shutdown mode.
PROG: Program, Monitor the charge current and Shutdown. This pin set to 1V in constant-current mode.
The charge current is programmed by connecting a 1% resistor, RPROG, to GND pin. The charge
current can be calculated using the following formula:
IBAT=(VPROG/RPROG)*1000
VER 1.2
2
ACE4054C
500mA/1.5A Standalone Linear Li-Ion Battery Charge
The PROG pin can also be used to switch the charger to shutdown mode by disconnecting the program
resistor from ground. This results in a 3μA current to pull the PROG pin to a high level shutdown threshold
voltage, thus stop the charging and reduce the supply current to 25μA. This pin is also clamped to
approximately 2.4V. A higher voltage beyond this value will draw currents as high as 1.5mA. Device
normal operation can be resumed by reconnecting the RPROG resistor to ground.
Ordering information
ACE4054C XX +
H
Halogen - free
Pb - free
GM : SOT-23-6
IM : ESOP-8
Block Diagram
VER 1.2
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ACE4054C
500mA/1.5A Standalone Linear Li-Ion Battery Charge
Electrical Characteristics
VCC=5V,TA=25℃, RPROG=10K, unless otherwise note.
Parameter
Symbol
Input Supply Voltage
VCC
Input Supply Current
Regulated Output (Float)
Voltage
BAT Pin Current
ICC
VFLOAT
IBAT
Conditions
Min
Units
6.0
V
Charge Mode(Note 2)
Standby Mode (Charge
Terminated)
Shutdown Mode (RPROG Not
Connected, VCC<VBAT, or
VCC<VULO)
300
2000
μA
200
500
μA
25
50
μA
IBAT=40mA
4.158
4.2
4.242
V
Current Mode
93
100
107
mA
RPROG=2K, Current Mode
465
500
535
mA
Standby Mode, VBAT=4.2V
Shutdown Mode (RPROG Not
Connected)
0
-2.5
-6
μA
1
5
μA
1
5
μA
ITRIKL
VBAT<VTRIKL, RPROG=2K
20
45
70
mA
VTRIKL
VBAT Rising
2.8
2.9
3
V
60
80
110
mV
2.7
2.8
2.92
V
150
200
300
mV
PROG Pin Rising
1.15
1.21
1.30
V
PROG Pin Falling
0.9
1
1.1
V
VCC from Low to High
70
100
140
mV
VCC from High to Low
5
30
50
mV
ITERM
Note 3
0.085
0.1
0.115
mA
VPROG
VCHRG
Current Mode, VBAT=4V
ICHRG=5mA
0.93
1
1.07
V
0.35
0.6
V
VRECHRG
VFLOAT-VRECHRG
100
150
200
mV
VTRHYS
VUV
From VCC Low to High
VUVHYS
Manual Shutdown
Threshold Voltage
VMSD
VCC-VBAT Lockout
Threshold Voltage
VASD
C/10 Termination Current
Threshold
PROG Pin Voltage
CHRG Pin Output Low
Voltage
Recharge BAT Threshold
Voltge
Junction Temperature in
Constant Temperature
Mode
Max
4.25
Sleep Mode, VCC=0V
Trickle Charge Current
Trickle Charge Threshold
Voltage
Trickle Charge Hysteresis
Voltage
VCC Undervoltage
Lockout Threshold
VCC Undervoltage
Lockout Hysteresis
Typ
TLIM
℃
120
VER 1.2
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ACE4054C
500mA/1.5A Standalone Linear Li-Ion Battery Charge
Power FET “ON”
Resistance (Between VCC
and BAT)
Soft-Start Time
RON
Tss
Recharge Comparator
tRECHARGE
Filter Time
Termination Comparator
tTERM
Filter Time
PROG Pin Pull-Up Current
IPROG
IBAT=0 to IBAT=1000V/RPROG
0.25
Ω
100
μs
VBAT High to Low
0.5
5
20
ms
IBAT Falling Below ICHG/10
400
1000
2500
μs
μA
3
Note 2.Supply current includes PROG pin current (approximately 100μA) but does not include any current delivered to the battery
through the BAT pin (approximately 100mA)
Note 3. ITREM is expressed as a fraction of measured full charge current with indicated PROG resistor
Application Circuit
ACE4054C
Typical Characteristic
(VCC=5V,TA=25℃, unless otherwise noted)
VER 1.2
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ACE4054C
500mA/1.5A Standalone Linear Li-Ion Battery Charge
Typical Characteristic
(VCC=5V,TA=25℃, unless otherwise noted)
VER 1.2
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ACE4054C
500mA/1.5A Standalone Linear Li-Ion Battery Charge
Typical Characteristic
(VCC=5V,TA=25℃, unless otherwise noted)
VER 1.2
7
ACE4054C
500mA/1.5A Standalone Linear Li-Ion Battery Charge
Detailed description
The ACE4054C is a single cell, fully integrated constant current(CC) /constant voltage (CV) Li-ion
battery charger. It can deliver up to 1.5A of charge current with a final float voltage accuracy of
ACE4054C has a build-in thermal regulation circuitry that ensures its safe operation. No blocking diode or
external current sense resistor is required; hence reduce the external components for a basic charger
circuit to two. The ACE4054C is also capable of operating from a USB power source.
Normal Charge Cycle
The ACE4054C initiates a charge cycle once the voltage at the VCC pin rises above the UVLO threshold
level. A ±1% precision resistor needs to be connected from the PROG pin to ground. If the voltage at the
BAT pin is less than 2.9V, the charger enters trickle charge mode. In this mode, the charge current is
reduced to nearly 1/10 the programmed value until the battery voltage is raised to a safe level for full
current charging.
The charger switches to constant-current mode as the BAT pin voltage rises above 2.9V, the charge
current is thus resumed to full programmed value. When the final float voltage (4.2V) is reached, the
ACE4054C enters constant-voltage mode and the charge current begins to decrease until it drops to 1/10
of the preset value and ends the charge cycle.
Programming Charge Current
The charge current is programmable by setting the value of a precision resistor connected from the
PROG pin to ground. The charge current is 1000 times of the current out of the PROG pin. The program
resistor and the charge current are calculated using the following equations:
RPROG = 1000V/ICHG
The charge current out of the BAT pin can be determined at any time by monitoring the PROG pin
voltage using the following equation:
IBAT=(VPROG/RPORG)*1000
ACE4054C has a self-temperature-limiting (STL) function, the chip starts to limit its charge current by
reducing VPROG gradually after silicon temperature rises above 70
and ambient
ACE4054C would have the same charge current and
junction temperature as chips without STL function at room temperature. As the ambient temperature
ACE4054C
would reduce its charge current and hence the junction temperature would be much lower. The STL
function helps to improve system reliability.
Charge Termination
The ACE4054C keeps monitoring the PROG pin during the charging process. It terminates the charge
cycle when the charge current falls to 1/10th the programmed value after the final float voltage is reached.
When the PROG pin voltage falls below 100mV for longer than tTERM (typically 1ms), charging is
terminated. The charge current is latched off and the ACE4054C enters standby mode, where the input
supply current drops to 200μA. (Note: C/10 termination is disabled in trickle charging and thermal limiting
modes).
VER 1.2
8
ACE4054C
500mA/1.5A Standalone Linear Li-Ion Battery Charge
During charging, the transient response of the circuit can cause the PROG pin to fall below 100mV
temporarily before the battery is fully charged, thus can cause a premature termination of the charge
cycle. A 1ms filter time (tTERM) on the termination comparator can prevent this from happening. Once the
average charge current drops below 1/10th the programmed value, the ACE4054C terminates the charge
cycle and ceases to provide any current through the BAT pin. In this state, all loads on the BAT pin must
be supplied by the battery.
The ACE4054C constantly monitors the BAT pin voltage in standby mode and resume another charge
cycle if this voltage drops below the recharge threshold (VRECHRG). User can also manually restart a
charge cycle in standby mode either by removing and then reapplied the input voltage or restart the
charger using the PROG pin. A diagram of typical charge cycle is shown in Figure 1.
Figure 1. Charge Cycle Diagram
Charge Status Indicator (CHRG)
There are two different states of the charge status output, namely pull-down and high impedance. The
pull-down state indicates that the ACE4054C is in a charge cycle. When the charge cycle has terminated,
the pin state is then determined by undervoltage lockout conditions. If the difference between VCC and
BAT pin voltage is less than 100mV or insufficient voltage is applied to the VCC pin, High impedance
appears on the charge statues pin.
VER 1.2
9
ACE4054C
500mA/1.5A Standalone Linear Li-Ion Battery Charge
Thermal Limiting
Build-in feedback circuitry mechanism can reduce the value of the programmed charge current once the
die temperature tends to rise above 120°C, hence prevents the temperature from further increase and
ensure device safe operation.
Undervoltage Lockout (UVLO)
Build-in undervoltage lockout circuit monitors the input voltage and keeps the charger in shutdown mode
until VCC rises above the undervoltage lockout threshold. The UVLO circuit has a built-in hysteresis of
200mV. Furthermore, to protect against reverse current in the power MOSFET, the UVLO circuit keeps
the charger in shutdown mode if VCC falls to within 30mV of the battery voltage. If the UVLO comparator
is tripped, the charger will not come out of shutdown mode until VCC rises 100mV above the battery
voltage.
Manual Shutdown
Floating the PROG pin by removing the resistor from PROG pin to ground can put the device in
shutdown mode. The battery drain current is thus reduced to less than 5μA and the supply current to less
than 50μA. Reconnecting the resistor back will restart a new charge cycle.
The CHRG pin is in a high impedance state if the ACE4054C is in undervoltage lockout mode.
Automatic Recharge
After the termination of the charge cycle, the ACE4054C constantly monitors the BAT pin voltage and
starts a new charge cycle when the battery voltage falls below 4.05V, keeping the battery at fully charged
condition. CHRG output enters a pull-down state during recharge cycles.
Applications Information
Stability Considerations
When a battery is connected to the output, the constant-voltage mode feedback is always stable.
However, in the case of absence of battery, an output capacitor is recommended to reduce ripple voltage.
In the case of high value capacitance or low ESR ceramic capacitors, a small value series resistor (~1Ω
recommended. No series resistor is needed if tantalum capacitors are used.
In constant-current mode, the PROG pin is in the feedback loop, thus its impedance affects the stability.
The maximum allowed value of the program resistor is 20K, and additional capacitance reduces this value.
The pole frequency at the PROG pin needs to be kept above 100kHz to maintain device stability.
Therefore, the maximum resistance value can be calculated from the following equation, CPROG is the
capacitance loaded to the PROG pin
Average rather than instantaneous charge current is more of a concern. A simple low pass filter can be
used on the PROG pin to measure the average battery current as shown in Figure 2. A 10K resistor has
been added between the PROG pin and the filter capacitor to ensure stability.
VER 1.2
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ACE4054C
500mA/1.5A Standalone Linear Li-Ion Battery Charge
ACE4054C
Figure 2. Isolating Capacitive Load on PROG Pin and Filtering
Power Dissipation
The power dissipated in the IC causes the rise of die temperature. Most of the power dissipation is
caused by the internal power MOSFET, and can be calculated by the following equation:
PD=(VCC-VBAT)*IBAT
Where PD is the power dissipated, VCC is the input supply voltage, VBAT is the battery voltage and
IBAT is the charge current. The approximate ambient temperature at which the thermal feedback begins
to protect the IC is:
TA=120℃-PDΘJA
TA=120℃-(VCC-VBAT)*IBAT*ΘJA
Example: An ACE4054C operating from a 5V USB supply is programmed to supply 400mA full-scale
current to a discharged Li-Ion battery with a voltage of 3.75V. Assuming ΘJA is 150°C /W (see Board
Layout Considerations), the ambient temperature at which the ACE4054C will begin to reduce the charge
current is approximately:
TA=120℃-(5V-3.75V)*(400mA)*150℃/W
TA=120℃-0.5W*150℃/W=120℃-75℃
TA=45℃
The ACE4054C can be used above 45°C ambient, but the charge current will be reduced from 400mA.
The approximate current at a given ambient temperature can be approximated by:
Using the previous example with an ambient temperature of 60°C, the charge current will be reduced to
approximately:
Moreover, when thermal feedback reduces the charge current, the voltage at the PROG pin is also
reduced proportionally as discussed in the operation section.
It is important to remember that ACE4054C applications do not need to be designed for worst-case
thermal conditions since the IC will automatically reduce power dissipation when the junction temperature
reaches approximately 120°C.
VER 1.2
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ACE4054C
500mA/1.5A Standalone Linear Li-Ion Battery Charge
Thermal Considerations
Due to its compact size, it is of great importance to use a good thermal PC board. Good thermal
conduction increases maximum allowed charge current value.
The thermal path for the heat generated by the IC is from the die to the copper lead frame, through the
package leads, (especially the ground lead) to the PC board copper. The PC board copper is the heat
sink. The footprint copper pads should be as wide as possible and expand out to larger copper areas to
spread and dissipate the heat to the surrounding ambient. Feed through vias to inner or backside copper
layers are also useful in improving the overall thermal performance of the charger. Other heat sources on
the board, not related to the charger, must also be considered when designing a PC board layout
because they will affect overall temperature rise and the maximum charge current.
Increasing Thermal Regulation Current
Reducing the voltage drop across the internal MOSFET can significantly decrease the power dissipation
in the IC. Minimized power dissipation results in reduced die temperature rise and hence equivalent
increased charge current in thermal regulation. One way is to bypass some of the current through an
external component, such as a resistor or diode.
Example: An ACE4054C operating from a 5V wall adapter is programmed to supply 600mA full-scale
current to a discharged Li-Ion battery with a voltage of 3.75V.
Assuming ΘJA is 125°C /W, the approximate charge current at an ambient temperature of 25°C is:
By dropping voltage across a resistor in series with a 5V wall adapter (shown in Figure 3), the on-chip
power dissipation can be decreased, thus increasing the thermally regulated charge current
ACE4054C
Figure 3. A Circuit to Maximize Thermal Mode Charge Current
VCC Bypass Capacitor
Due to their self-resonant and high Q characteristics, some types of ceramic capacitors can cause high
voltage transients under some start-up conditions (i.e connecting the charger input to a live power source).
Adding a small value resistor in series with the ceramic capacitor can minimize start-up voltage transients
VER 1.2
12
ACE4054C
500mA/1.5A Standalone Linear Li-Ion Battery Charge
Charge Current Soft-Start
To avoid the start-up transients, a soft-start circuit is included to ramp the charge current from zero to
programmed value over a period of time. This has the effect of minimizing the transient current load on
the power supply during start-up.
Packing Information
SOT-23-6
VER 1.2
13
ACE4054C
500mA/1.5A Standalone Linear Li-Ion Battery Charge
Packing Information
ESOP-8
HEAT SLUG
(BTM)
NOTES: ALL DIMENSIONS REFER TO JEDEC STANDARD MS-012 AA DO NOT INCLUDE MOLD
FLASH OR PROTRUSIONS.
BASE METAL
SECTION B-B
VER 1.2
14
ACE4054C
500mA/1.5A Standalone Linear Li-Ion Battery Charge
Notes
ACE does not assume any responsibility for use as critical components in life support devices or systems
without the express written approval of the president and general counsel of ACE Electronics Co., LTD.
As sued herein:
1. Life support devices or systems are devices or systems which, (a) are intended for surgical implant
into the body, or (b) support or sustain life, and shoes failure to perform when properly used in
accordance with instructions for use provided in the labeling, can be reasonably expected to result in
a significant injury to the user.
2. A critical component is any component of a life support device or system whose failure to perform can
be reasonably expected to cause the failure of the life support device or system, or to affect its safety
or effectiveness.
ACE Technology Co., LTD.
http://www.ace-ele.com/
VER 1.2
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