ADP3801AR ,High Frequency Switch Mode Dual Li-Ion Battery ChargersSPECIFICATIONS AParameter Conditions Symbol Min Typ Max UnitsFINAL BATTERY VOLTAGEOne Li-Ion Cell P ..
ADP3801AR ,High Frequency Switch Mode Dual Li-Ion Battery ChargersFEATURES FUNCTIONAL BLOCK DIAGRAMStand-Alone Li-Ion Battery ChargersHigh End-of-Charge Voltage Accu ..
ADP3802 ,500 kHz, High Frequency Switch Mode Dual Li-Ion Battery ChargerGENERAL DESCRIPTIONThe ADP3801 and ADP3802 are complete battery chargingVCC DRV CS+ CS– A/BEOC3.3VI ..
ADP3802AR ,High Frequency Switch Mode Dual Li-Ion Battery ChargersAPPLICATIONSFast ChargersUniversal ChargersCellular PhonesPortable Computers68mHPortable Instrument ..
ADP3802AR ,High Frequency Switch Mode Dual Li-Ion Battery ChargersGENERAL DESCRIPTIONThe ADP3801 and ADP3802 are complete battery chargingVCC DRV CS+ CS– A/BEOC3.3VI ..
ADP3804JRU-12.5-RL ,High Frequency Switch Mode Li-Ion Battery ChargerSPECIFICATIONSParameter Conditions Symbol Min Typ Max UnitsBATTERY SENSE INPUTADP3804-12.6V T +25 ..
AK4646EN , Stereo CODEC with MIC/SPK-AMP
AK4648EC , Stereo CODEC with MIC/HP/SPK-AMP
AK4665AEN , 20-Bit Stereo CODEC with MIC/HP-AMP
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ADP3801AR-ADP3802AR
High Frequency Switch Mode Dual Li-Ion Battery Chargers
REV.0
High Frequency Switch Mode
Dual Li-Ion Battery Chargers
FUNCTIONAL BLOCK DIAGRAM
DRVVCCCS+CS–A/B
PROG
ADJCOMPGND
RESET
ISET
BATB
BATA
EOC
FEATURES
Stand-Alone Li-Ion Battery Chargers
High End-of-Charge Voltage Accuracy60.4% @ +258C
60.75% @ –108C to +708C
Intelligent End-of-Charge Output Signal
Pin Programmable Cell Number Select
On Chip 3.3 V LDO Regulator
Programmable Charge Current with High Side Sense
Softstart Charge Current
Undervoltage Lockout
Drives External PMOS610% Adjustable End-of-Charge Voltage
Charges NiCad, NiMH (with External mController)
PWM Oscillator Frequency:
ADP3801: 200 kHz
ADP3802: 500 kHz
APPLICATIONS
Fast Chargers
Universal Chargers
Cellular Phones
Portable Computers
Portable Instrumentation
Desktop Chargers
Personal Digital Assistants
GENERAL DESCRIPTIONThe ADP3801 and ADP3802 are complete battery charging
ICs. The devices combine a high accuracy final battery voltage
control with a constant charge current control and an on-board
Low Drop-Out Regulator (LDO). The accuracy of the final
battery voltage control is guaranteed to –0.75% to safely charge
Li-Ion batteries. An internal multiplexer allows the alternate
charging of two separate battery stacks. The final voltage is pin
programmable to one of three Li-Ion options: 4.2 V (one Li-Ion
cell), 8.4 V (two Li-Ion cells), or 12.6 V (three Li-Ion cells).
Paired with an external microcontroller for charge termination,
the ADP3801/ADP3802 works as a fast charger for NiCad/
NiMH batteries or as a universal charger for all three battery
chemistries. In addition, a pin is provided for changing the final
battery voltage by up to –10% to adjust for variations in battery
chemistry from different Li-Ion manufacturers without loss of
accuracy in the final battery voltage.
Figure 1.4 Amp Dual Battery Charger
ADP3801/ADP3802–SPECIFICATIONSBATTERY PROGRAMMING
CURRENT SENSE AMPLIFIER
(@ –408C £ TA £ +858C, VCC = 10.0 V, unless otherwise noted)
ADP3801/ADP3802NOTESVCC = VBAT + 2 V.See Figure 5.VCS = (VCS+) – (VCS–).Accuracy guaranteed by ISET INPUT, Programming Function Accuracy specification.EOC Output Comparator monitors charge current, and it is enabled when VBAT ‡ 95% of the final battery voltage.LDO is active during SD and UVLO.Turn-off threshold depends on LDO dropout.
All limits at temperature extremes are guaranteed via correlation using standard Statistical Quality Control (SQC) methods.
Specifications subject to change without notice.
ADP3801/ADP3802
PIN CONFIGURATION
ABSOLUTE MAXIMUM RATINGS*Input Voltage (VCC to GND) . . . . . . . . . . . . . .–0.3V to 20 V
DRV, VCS+, VCS– to GND . . . . . . . . . . . . . . . . –0.3 V to VCC
BATA, BATB to GND . . . . . . . . . . . . . . . . . –0.3 V to 14.0 V
A/B, ISET, PROG, ADJ to GND . . . . . . . . . . . –0.3 V to VL
SD, RESET, COMP, EOC to GND . . . . . . . . . . –0.3 V to VL
Power Dissipation . . . . . . . . . . . . . . . . . . . . Internally LimitedJA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75°C/W
Ambient Temperature Range . . . . . . . . . . . . –40°C to +85°C
Storage Temperature Range . . . . . . . . . . . . –65°C to +150°C
Lead Temperature Range (Soldering 10 sec) . . . . . . . +300°C
NOTES
*This is a stress rating only and functional operation of the device at these or any
other conditions above those indicated in the operation section of this specification
is not implied. Exposure to absolute maximum rating conditions for extended
periods may affect device reliability.JA is specified for worst case conditions with device soldered on a circuit board.
ORDERING GUIDE
CAUTIONESD (electrostatic discharge) sensitive device. Electrostatic charges as high as 4000V readily
accumulate on the human body and test equipment and can discharge without detection. Although
the ADP3801/ADP3802 features proprietary ESD protection circuitry, permanent damage may
occur on devices subjected to high energy electrostatic discharges. Therefore, proper ESD precau-
tions are recommended to avoid performance degradation or loss of functionality.
PIN FUNCTION DESCRIPTIONSNOTE“L” = Battery “A.”
VBAT ACCURACY – %
TOTAL NUMBEROF PARTS
100Figure 2.VBAT Accuracy Distribution
VADJ – Volts
BAT
PERCENT CHANGE – %0.51.01.52.03.03.5
2.5Figure 5.VBAT Percent Change vs. VADJ
LDO LOAD CURRENT – mA
UVLO TRIP POINT – Votts23467
3.7910Figure 8.UVLO Trip Point-Off vs.
LDO Load Current
TEMPERATURE – 8C
BAT
ACCURACY – %
0.4Figure 3.VBAT Accuracy vs.
Temperature
TEMPERATURE – 8C
THRESHOLD – %
–40–200204080100Figure 6.Overvoltage Comparator
Threshold vs. Temperature
TEMPERATURE – 8C
LDO ACCURACY – %
–20020406080100Figure 9.LDO Accuracy vs.
Temperature
SUPPLY VOLTAGE – Volts
BAT
ACCURACY – %81012141820
0.3Figure 4.VBAT Accuracy vs. Supply
Voltage
TEMPERATURE – 8C
THRESHOLD – mV
200Figure 7.Overcurrent Comparator
Threshold vs. Temperature
Figure 10.LDO Accuracy vs. Supply
Voltage
ADP3801/ADP3802
LOAD CURRENT – mA
DROPOUT VOLTAGE – Volts2346758
0.4Figure 11.LDO Dropout Voltage vs.
Load Current
VCOMP – Volts
DUTY CYCLE – %0.52.02.53.0
100Figure 14.Duty Cycle vs. COMP Pin
Voltage
TEMPERATURE – 8C
CLAMP VOLTAGE – Volts
3.9Figure 17.DRV Output Low Voltage
with VCC = 10 V vs. Temperature
FREQUENCY – Hz
PSRR – dB
1.0E+01
1.0E+021.0E+031.0E+041.0E+051.0E+06Figure 12.LDO PSRR vs. Frequency
TIME – ns
DRV – VoltsFigure 15.DRV Rise and Fall Times
SUPPLY VOLTAGE – Volts
POWER SUPPLY CURRENT – mA16
5.5 Figure 18.Power Supply Current vs.
Supply Voltage @ Three Temperatures
TEMPERATURE – 8C
FREQUENCY – kHz
205Figure 13.Oscillator Frequency vs.
Temperature
Figure 16.DRV High Saturation Volt-
age vs. Temperature
CAPACITIVE LOAD – nF
POWER SUPPLY CURRENT – mA0.51.5
2.01.02.5Figure 19.Power Supply Current vs.
Capacitive Load on DRV
APPLICATIONS SECTION
PRODUCT DESCRIPTIONThe ADP3801 and ADP3802 are complete Li-Ion battery charg-
ing ICs. Combined with a microcontroller, they also function as
voltage limited, mC programmable constant current source chargers
for NiCad and NiMH chemistries. Utilizing an external PMOS
pass transistor, the devices realize a buck type constant current,
constant voltage (CCCV) charger controller that is capable of
charging two separate battery packs for such applications as
portable computer chargers and cellular phone chargers. The
Functional Block Diagram shows the ICs’ functional blocks,
which are detailed below:A/B SELECT MUX—Two-channel multiplexer for charging
two battery stacks.FINAL BATTERY VOLTAGE PROGRAM—Multiplexer to
program 4.2V, 8.4V, or 12.6V final battery voltage.VOLTAGE LOOP AMP—GM-type amplifier to control
the final battery voltage. It includes a built-in overvoltage
comparator.EOC COMPARATOR—End-of-charge detection output to
signal when the battery is fully charged.BATTERY VOLTAGE ADJUST—Amplifier to adjust the
final battery voltage up to –10%.CURRENT LOOP AMP—High-side-current-sense amplifier
to sense and control the charge current at a programmable
level. It includes an overcurrent comparator.PWM—Pulsewidth modulator and oscillator (ADP3801-
200kHz, ADP3802-500kHz).GATE DRIVE—Gate drive to control an external pass tran-
sistor. It includes a clamp to limit the drive voltage to protect
the external PMOS.LDO + REFERENCE—3.3V low dropout regulator to sup-
ply an external microcrontroller and for on-chip supply. In-
cludes an internal precision reference (VREF = VL/2).SHUTDOWN—Logic input to shut down the charger. The
LDO remains on.UVLO—Undervoltage lockout circuit to shut down the charger
for low supply voltages.RESET—Active LOW output to reset external logic on power-
up.
During charging, the ADP3801/ADP3802 maintains a constant,
programmable charge current. The high side current sense
amplifier has low offset allowing the use of a low voltage drop
for current sensing: 165mV for the maximum charge current.
The input common-mode range extends from ground to
VCC – 2V ensuring current control over the full charging volt-
age of the battery, including a short circuit condition. A high
impedance dc voltage input (ISET) is provided for program-
ming the charge current over a wide range. When the battery
voltage approaches its final limit, the part automatically trans-
fers to voltage control mode. Both the current control loop and
the voltage control loop share the same compensation pin mini-
mizing the number of external components. An internal com-
A 3.3V LDO is used to generate a regulated supply for internal
circuitry. Additionally, the LDO can deliver up to 10mA of
current to power external circuitry such as a microcontroller. An
Undervoltage Lockout (UVLO) circuit is included to safely shut
down the charging circuitry when the input voltage drops below
its minimum rating. A shutdown pin is also provided to turn off
the charger when, for example, the battery has been fully charged.
The LDO remains active during shutdown or UVLO and has a
quiescent current of 110mA.
Battery Charging OverviewFigure 20 shows a simplified Buck type battery charger applica-
tion circuit for the ADP3801/ADP3802. When a discharged
battery is first placed in the charger, the battery voltage is well
below the final charge voltage, so the current sense amplifier
controls the charge loop in constant current mode. The charge
current creates a voltage drop across the sense resistor RCS. This
voltage drop is buffered and amplified by amplifier GM1. Am-
plifier GM2 compares the output of GM1 to an external current
control voltage provided at the ISET pin and servos the charger
loop to make these voltages equal. Thus, the charge current is
programmed using the ISET input voltage.
The output of GM2 is analog “OR’ed” with the output of GM3,
the voltage loop amplifier. Only one or the other amplifier con-
trols the charge loop at any given time. As the battery voltage
approaches its final voltage, GM3 comes into balance. As this
occurs, the charge current decreases, unbalancing GM2, and
control of the feedback loop naturally transfers to GM3.
The ADP3801/ADP3802 can control the charging of two inde-
pendent battery stacks or a single battery stack. The A/B SELECT
MUX has a logic input to choose between the two batteries. See
Figure 31 for more information on dual battery charging. The
output of the multiplexer is applied to a precision thin-film
resistor string to divide down the battery voltage. The final
battery voltage is chosen by selecting the proper resistor divider
tap with the PROG multiplexer. The output of this mux goes
directly to the input of GM3, comparing the divided down
battery voltage to the internal reference. To guarantee –0.75%
accuracy, a high precision internal reference and high accuracy
thin film resistors are used. Including these components on-
chip saves the significant cost and design effort of adding them
externally.
ADP3801/ADP3802
RESETRCS
3.3V
BATA
(FROM mC)
(TO mC)
(TO mC)Figure 20. Simplified Application Diagram
Setting the Final Battery VoltageThe final battery voltage is determined by the voltage on the
Battery Programming (PROG) pin. This pin controls the state
of the PROG multiplexer, which selects the appropriate tap
from the internal battery voltage resistor divider. The specifica-
tion table details the PROG voltages for each final battery volt-
age. A resistor divider from the LDO can be used to set the
PROG voltage as shown in Figure 21. To provide fail safe op-
eration, a PROG voltage equal to 0.0V or 3.3V results in the
minimum final battery voltage of 4.2V. The PROG input is
high impedance, so the voltage can be set with a high imped-
ance resistor divider from VL. Alternatively, a PWM output
from a microcontroller can be used with an RC filter to generate
the desired threshold voltage.
PROG
*CONNECT PROG TO
GND FOR VBAT = 4.2VFigure 21.Resistor Divider Sets the Final Battery Voltage
Adjusting the Final Battery VoltageIn addition to the PROG input, the ADP3801/ADP3802 pro-
vides an input (ADJ) for fine adjustment of the final battery
voltage. For example, the ADJ amplifier allows the nominal
4.2V per cell setting for Li-Ion battery cells to be adjusted to
4.1V for certain chemistries. An internal amplifier buffers the
ADJ pin and adjusts the internal reference voltage on the input
to GM3. Figure 5 shows a graph of the percent change in final
battery voltage vs. the ADJ voltage. The linear portion between
0.6 VREF and 1.4VREF follows the formula below:
The factor of four in the denominator is due to internal scaling.
When VADJ is above 2.5V, an internal comparator switches off
the ADJ amplifier, giving a 0% change in VBAT. Whenever the
ADJ function is not used it should be connected to VL.
The total range of adjustment is –10%. For example, the 4.2V
final battery voltage setting can be adjusted from 3.78V to
4.62V. Of course, care must be taken not to adjust the final
battery voltage to an unsafe charging level for Li-Ion batteries.
Follow the battery manufacturers specifications for the appro-
priate final battery voltage. Never charge a Li-Ion battery above
the manufacturers rated maximum!
Voltage Loop AccuracyThe ADP3801/ADP3802 guarantees that the battery voltage be
within –0.75% of the setpoint over the specified temperature
range and the specified charge current range. This inclusive
specification saves the designer the time and expense of having
to design-in additional high accuracy components such as a
reference and precision resistors.
To maintain the –0.75% specification, the layout and design of
the external circuitry must be considered. The input impedance
of BATA and BATB is typically 265kW, so any additional im-
pedance on these inputs will cause an error. As a result, do not
add external resistors to the battery inputs. Furthermore, if the
output voltage is being used for other purposes, such as to sup-
ply additional circuitry, the current to this circuitry should be
routed separately from the sense lines to prevent voltage drops
due to impedance of the PC-board traces. In general, route the
sense lines as Kelvin connections as close to the positive termi-
nals of the battery as possible.
The same care must be given to the ground connection for the
ADP3801/ADP3802. Any voltage difference between the bat-
tery ground and the GND pin will cause an error in the charge
voltage. This error includes the voltage drop due to the ground
current of the part. Thus, the GND pin should have a thick
trace or ground plane connected as close as possible to the
battery’s negative terminal. Any current from additional cir-
cuitry should be routed separately to the supply return and not
share a trace with the GND pin.
Dual Battery OperationThe ADP3801/ADP3802 is designed to charge two separate
battery packs. These batteries can be of different chemistries
and have a different number of cells. At any given time, only
one of the two batteries is being charged. To select which bat-
tery is being monitored, and therefore which battery is being
charged, the ADP3801/ADP3802 includes a battery selector
mux. This two-channel mux is designed to be “break-before-
make” to ensure that the two batteries are not shorted together
momentarily when switching from one to the other. The A/B
input is a standard logic input, with a logic low selecting BATA
and a logic high selecting BATB. See the application in Figure
31 for more information.
Overvoltage ComparatorGM3 includes an overvoltage comparator. Its output bypasses
the COMP node to quickly reduce the duty cycle of the PWM
to 0% when an overvoltage event occurs. A second output is
connected to the COMP node and, with slower response, re-
duces the voltage on the COMP cap to provide a soft start re-
covery. The threshold of the comparator is typically 8% above
the final battery voltage. This comparator protects external
circuitry from any condition that causes the output voltage to
quickly increase. The most likely reason is if the battery is
suddenly removed while it is being charged with high current.
Figure 27 shows the transient response when the battery is
removed. Notice that the output voltage increases to the com-
parator trip point, but it is quickly brought under control and
held at the final battery voltage.
ADP3801/ADP3802
Current Sense AmplifierA differential, high side current sense amplifier (GM1 in Figure
20) amplifies the voltage drop across a current sense resistor
RCS. The input common-mode range of GM1 extends from
ground to VCC – 2V. Sensing to ground ensures current regu-
lation even in short circuit conditions. To stay within the com-
mon-mode range of GM1, VCC must be at least 2 V greater
than the final battery voltage or a circuit such as shown in Fig-
ure 32 must be used. RC filters are included to filter out high
frequency transients, which could saturate the internal circuitry.
The filter’s cutoff is typically set at half the switching frequency
of the oscillator.
The charge current is controlled by the voltage on the ISET pin
according to the following formula:
The factor of 10 is due the GM1’s gain of 10V/V. To set a charge
current of 1.5A with RCS = 0.1W, VISET must be 1.5V. Figure
22 shows the linearity of the charge current control as the volt-
age is increased from 0V to the programmed final battery volt-
age (12.6V in this case). It is important to state that this curve
is taken with an ideal, zero impedance load. An actual Li-Ion
battery will exhibit a more gradual drop in charge current due to
the internal impedance of the battery as shown in Figure 25.
VOUT – Volts
CHARGE
– Amps678910
3.5Figure 22. CCCV Characteristic with Ideal Load
Overcurrent ComparatorSimilar to the voltage loop, the current loop includes a com-
parator to protect the external circuitry from an overcurrent
event. This comparator trips when GM1’s differential input
voltage exceeds 185mV. Like the overvoltage comparator, it has
two outputs to quickly reduce the duty cycle to 0% and to pro-
vide a soft-start recovery. The response time of the internal
comparator is approximately 1ms; however, the filter on the
input of GM1 may slow down the total response time of the
loop.
End-of-Charge OutputThe ADP3801/ADP3802 provides an active low, end-of-charge
(EOC) logic output to signal when the battery has completed
charging. The typical Li-Ion charging characteristic in Figure 25
shows that when the battery reaches its final voltage the current
decreases. To determine EOC, an internal comparator senses
when the current falls below 6% of full scale, ensuring that the
battery has been fully charged. The comparator has hysteresis to
prevent oscillation around the trip point.
To prevent false triggering (such as during soft-start), the com-
parator is only enabled when the battery voltage is within 5% of
its final voltage. As the battery is charging up, the comparator
will not go low even if the current falls below 6% as long as the
battery voltage is below 95% of full scale. Once the battery has
risen above 95%, the comparator is enabled.
There are two important reasons for this functionality. First,
when the circuit is initially powered on, the charge current is
zero because of the soft start. If the comparator is not gated by
the battery voltage, then EOC would go low erroneously. Sec-
ond, a provision must be made for battery discharge. Assume
that a battery has been fully charged. EOC goes low, and the
charger is gated off. When the battery voltage falls to 95%, due
to self-discharge for example, EOC will return high. Then the
charger can start up and top off the battery, preventing the
battery from “floating” at the end-of-charge voltage.
The EOC output has many possible uses as shown in Figure 23.
One simple function is to terminate the charging to prevent
floating (Figure 23a). It can be used as a logic signal to a
microcontroller to indicate that the battery has finished charg-
ing. The microcontroller can then switch to the next battery if
appropriate or shutdown the ADP3801/ADP3802. It can also be
used to turn on an LED to signal charge completion (Figure
23b). Using a flip-flop, EOC can control the switching from
BATA to BATB (Figure 23d). The RC filter delays switching
between the two batteries to ensure that the output capacitor is
discharged.
