ACT3780 - Active-Semi

ACT3780
Rev 8, 09-Jul-13
ActivePathTM Battery Charger
FEATURES
GENERAL DESCRIPTION
• ActivePath
The ACT3780 is a complete battery-charging and
system power management solution for portable
hand-held equipment using single-cell Lithiumbased batteries. The ACT3780 incorporates ActiveSemi's proprietary ActivePath architecture which
automatically selects the best available input supply
for the system.
•
•
•
•
•
•
•
•
•
•
•
•
•
•
TM
System Power Selection of Best
Available Input Supply
50mΩ Battery Switch for Highest Efficiency
Dynamic Control of Charging Current Allowing
System to Draw Maximum Load from AC/USB
Input
±0.5% Battery Charge Voltage Accuracy
Up to 12V Input with Over Voltage Protection
Thermal Regulation for Charge Control
Charge Status Outputs for LED or System
Interface
Battery Voltage Level Indication
Programmable Fast Charge Current
Programmable Charging Timer
Low Reverse Leakage Current
Short-Circuit and Thermal Protection
Preconditioning for Deeply Depleted Battery
Low Quiescent Current Standby Mode
Space-Saving, Thermally-Enhanced
TQFN44-20 Packages
The ActivePath architecture performs three
important functions: First, the battery is charged
while powering with the system, minimizing current
draw from the battery while ensuring that sufficient
current is available to power the system. Second, if
no input supply is available, system power is
automatically switched to the battery. And finally, if
the system load-requirement exceeds the capability
of the input supply, ActivePath automatically
supplements the input with the battery to satisfy the
system's power requirements.
In addition to ActivePath, the ACT3780 charger
features a complete, high-accuracy (±0.5%),
thermally regulated, stand-alone single cell linear
Li+ charger with an integrated 12V power
MOSFET. The ACT3780 is available in a thermally
enhanced 4mm × 4mm Thin-QFN44-20.
APPLICATIONS
•
•
•
•
•
Personal Navigation Devices
Smart Mobile Phones
Blue-Tooth Devices
Portable Media Players
Portable Devices
ActivePath DIAGRAM
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ACT3780
Rev 8, 09-Jul-13
ORDERING INFORMATIONcd
PART NUMBER
BATTERY
VOLTAGE
SYSTEM
VOLTAGE
PACKAGE
PINS
TEMPERATURE
RANGE
ACT3780QY-T
4.2V
4.6V
TQFN44-20
20
-40°C to 85°C
ACT3780QY410-T
4.1V
4.6V
TQFN44-20
20
-40°C to 85°C
c: All Active-Semi components are RoHS Compliant and with Pb-free plating unless specified differently. The term Pb-free means
semiconductor products that are in compliance with current RoHS (Restriction of Hazardous Substances) standards.
d: Standard product options are identified in this table. Contact factory for custom options. Minimum order quantity is 12,000 units.
PIN CONFIGURATION
Top View
20
19
18
17
16
nACOK
1
15
TH
nBLV1
2
14
ACIN
nBLV2
3
13
G
nSTAT3
4
12
ISET
nSTAT1
5
11
EN
ACT3780QY
6
7
8
9
10
Thin-QFN44-20
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ACT3780
Rev 8, 09-Jul-13
PIN DESCRIPTIONS
PIN
NAME
1
nACOK
CHG_IN Status Output. nACOK is an open-drain which sinks current whenever VCHG_IN is
within it's valid operating range.
2
nBLV1
Battery Voltage level Monitor Output 1. Open-drain output that sinks current when asserted.
Connect a 10k or greater pull-up resistors between nBLV1 and a suitable voltage supply. See
Battery Voltage Level Indication Section for more information.
3
nBLV2
Battery Voltage level Monitor Output 2. Open-drain output that sinks current when asserted.
Connect a 10k or greater pull-up resistors between nBLV2 and a suitable voltage supply. See
Battery Voltage Level Indication Section for more information.
4
nSTAT3
CHG_IN OVP Status Output. Open-drain output that sinks current whenever VCHG_IN is greater
than OVP threshold 6.9V (typ) while battery is present. For a logic-level charge status indicator,
simply connect a 10k or greater pull-up resistor between nSTAT3 and a suitable voltage supply.
nSTAT1
Charge State Indicator. Open-drain output with an internal 6mA current limit, allowing this pin
to directly drive an indicator LED. For a logic-level charge status indicator, simply connect a
10k or greater pull-up resistor between nSTAT1 and a suitable voltage supply. See the
Charging Status Indication Section for more information.
6
nSTAT2
Charge State Indicator. Open-drain output with an internal 6mA current limit, allowing this pin
to directly drive an indicator LED. For a logic-level charge status indicator, simply connect a
10k or greater pull-up resistor between nSTAT2 and a suitable voltage supply. See the
Charging Status Indication Section for more information.
13
G
7
CHG_IN
Power Input. Bypass to G with a high quality ceramic capacitor placed as close to the IC as
possible.
8, 9
BAT
Battery Charger output. Connect this pin to the positive terminal of the battery. Bypass to G
with a high quality ceramic capacitor placed as close to the IC as possible.
10
CHGLEV
Charging State Select Input. Drive CHGLEV to VSYS or to a logic high for high-current
charging mode or drive to G or a logic low for low-current charging mode. See the ACIN and
CHGLEV Inputs section for more information.
11
EN
EN Charger Enable Input. Drive to a logic high to enable IC, drive to a logic low to disable the
device and enter suspend mode.
12
ISET
Charge Current Set Input. Connect a resistor from ISET to G to set the fast-charge current.
14
ACIN
AC Adaptor Detect Logic Input. Detects presence of a wall adaptor and automatically adjusts
the charge current to the maximum charge current level. See the ACIN and CHGLEV Inputs
section for more information.
15
TH
16
DCCC
Dynamic Control of Charging Current Set Input. Connect a resistor from DCCC to G to set the
DCCC voltage. See the Dynamic Charge Current Control section for more information.
17
BTR
Safety Timer Programming Input. Connect a resistor from BTR to G to set the safety timers. Do
not leave this pin floating. See the Charging Safety Timers Section for more information.
18, 19,
20
SYS
System Power Output. Bypass to G with a high quality ceramic capacitor placed as close to the
IC as possible.
5
EP
DESCRIPTION
Ground.
Temperature Sensing Input. Connect to battery thermistor terminal. See the Battery
Temperature Monitoring section for more information.
Exposed Pad. Must be soldered to ground on the PCB.
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ACT3780
Rev 8, 09-Jul-13
ABSOLUTE MAXIMUM RATINGSc
PARAMETER
VALUE
UNIT
CHG_IN to G
-0.3 to + 14
V
BAT, SYS, BTR, ISET, DCCC, ACIN, CHGLEV, EN, TH, nACOK, nSTAT1, nSTAT2,
nSTAT3, nBLV1, nBLV2 to G
-0.3 to + 6
V
3.5
A
4
A
Maximum Junction Temperature
-40 to 150
°C
Storage Temperature
-60 to 150
°C
300
°C
Input Current
Output Current (Internal Limit) BAT to SYS
Lead Temperature (Soldering, 10 sec)
c: Do not exceed these limits to prevent damage to the device. Exposure to absolute maximum rating conditions for long periods may
affect device reliability.
ELECTRICAL CHARACTERISTICS
(VCHG_IN = 5.0V, RISET = 1kΩ, RBTR = 62kΩ, RDCCC = 18.7kΩ, TA = 25°C, unless otherwise specified.)
PARAMETER
SYMBOL
TEST CONDITIONS
MIN
TYP
MAX UNIT
ActivePath
CHG_IN Voltage Range
VCHG_IN
CHG_IN UVLO Voltage
VUVLO
CHG_IN UVLO Hysteresis
4.35
Voltage Rising
3.65
VHYS(UVLO)
CHG_IN OVP Threshold
VOVP
CHG_IN OVP Hysteresis
VHYS(OVP)
CHG_IN to SYS On-Resistance
Voltage Rising
6.60
CHG_IN to SYS Current Limit
6.90
60
V
V
7.20
0.3
ACIN = 1
V
mV
200
1.8
RDSON_Q1 ISYS = 100mA
IUSB
4.05
360
TM
ISUP(CHG_IN) VCHG_IN = 6V, VBAT = 4.3V, ActivePath
Enabled and SYS No Load, Charger
in EOC or Time Out state or Disabled.
IAC
V
1.25
VCHG_IN = 6V, VBAT float
CHG_IN Supply Current
3.85
12
µA
mA
0.5
2.5
Ω
A
ACIN = G, CHGLEV = G
80
90
100
mA
ACIN = G, CHGLEV = SYS
400
450
500
mA
4.4
4.6
4.8
V
90
100
110
µA
SYS and DCCC Regulation
SYS Regulated Voltage
DCCC Pull-Up Current
VSYS_REG ISYS = 100mA
IDCCC
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ACT3780
Rev 8, 09-Jul-13
ELECTRICAL CHARACTERISTICS CONT’D
(VCHG_IN = 5.0V, RISET = 1kΩ, RBTR = 62kΩ, RDCCC = 18.7kΩ, TA = 25°C, unless otherwise specified.)
PARAMETER
SYMBOL
TEST CONDITIONS
MIN
TYP
MAX UNIT
Charger
BAT to SYS On Resistance
RDSON_Q2
SYS to BAT Turn On
Threshold
VCHG_ON
SYS - BAT
40
SYS to BAT Turn Off
Threshold
VCHG_OFF
SYS - BAT
-30
Charge Termination Voltage
Battery Reverse Leakage
Current
VTERM
IBAT_REV
4.179
4.200
4.221
ACT3780QY410
4.075
4.100
4.125
VSYS < VBAT + 100mV, ISYS = 0mA
2.5
5
VSYS = 4.5V to 5.5V, IBAT = 10mA
0.025
VFSTSET
Fast Charge
VPRESET
Precondition Charge
IFSTCHG
ACIN = SYS, CHGLEV = SYS
ACIN = G, CHGLEV = G
IPRECHG
VBAT = 2.5V
100
400
450
500
-17.5% 0.5*ISET 17.5%
10%
ISET
ACIN = SYS, CHGLEV = SYS
10%
ISET
Precondition Voltage
Threshold
VPRECHG
VBAT Voltage Rising
2.7
VHYS(PRECHG) VBAT Voltage Falling
VBAT = 4.2V
mA
12.5%
MIN(10%ISET, 90mA)
ACIN = SYS, CHGLEV = G
VCHG_IN = 5V, Charger is in EOC state or
time-out fault state or disabled.
IEOC
ISETe
10%
ISET
ILKG_BAT
End-of Charge Current
Threshold
90
ACIN = G, CHGLEV = SYS
Leakage Current to BAT
Precondition Threshold
Hysteresis
80
-12.5%
µA
V
0.1
VBAT = 3.5V ACIN = G, CHGLEV = SYS
RISET = 1kΩ ACIN = SYS, CHGLEV = G
V
%/V
1
2
Precondition Charge Current
75
ACT3780QY
TA = 25°C
ACIN = G, CHGLEV = Gc
Charge Current
mΩ
mV
Line Regulation
ISET Pin Voltage
50
mA
0
5
µA
2.85
3.00
V
150
220
mV
ACIN = G
4
ACIN = SYS
10
%
Sleep-Mode Entry Threshold
VSLPENT
150
250
mV
Sleep-Mode Exit Threshold
VSLPEXIT
50
150
mV
Charge Restart Threshold
VRCH
175
200
mV
Fast Charge Safety Timer
TNORMAL
Precondition Safety Timer
TPRE
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VSYS – VBAT, VBAT Falling
RBTR = 62kΩ
3
f
RBTR = 62kΩ
1
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hr
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ACT3780
Rev 8, 09-Jul-13
ELECTRICAL CHARACTERISTICS CONT’D
(VCHG_IN = 5.0V, RISET = 1kΩ, RBTR = 62kΩ, RDCCC = 18.7kΩ, TA = 25°C, unless otherwise specified.)
PARAMETER
SYMBOL
TEST CONDITIONS
MIN
TYP
MAX UNIT
92
100
108
µA
Temperature Sense Comparator
TH Pull-Up Current
ITH
VCHG_IN > VBAT + 200mV
VTH Upper Temperature Voltage
Threshold
VTHH
Down-going, simulate a NTC going
hotter
0.475
0.505
0.535
V
VTH Lower Temperature Voltage
Threshold
VTHL
Up-going, simulate a NTC going colder
2.440
2.510
2.580
V
VTH Hysteresis
VHYS
30
45
mV
EN, ACIN and CHGLEV Inputs
EN, ACIN, CHGLEV Pin Logic
High Input Voltage
VIH
EN, ACIN, CHGLEV Pin Logic
Low Input Voltage
VIL
EN Pin Logic Leakage Current
ILKG1
1.4
V
VCHG_IN = 4.2V, EN = SYS
0.4
V
1
µA
8
mA
nSTAT1, nSTAT2, nSTAT3, nACOK, nBLV1, nBLV2 Outputs
Sink Current
InSTATx
Output Low Voltage
Leakage Current
nSTAT1, nSTAT2
4
6
VOL
nSTAT1, nSTAT2, nSTAT3, nACOK,
Isink = 1mA
0.5
V
VLOL
nBLV1, nBLV2, InBLVx = 2mA
0.3
V
ILKG2
nSTAT1, nSTAT2, nSTAT3, nACOK,
nBLV1, nBLV2, VnSTATx = VnACOK = 5V
1
µA
Thermal Shutdown Regulation
Thermal Regulation Threshold
TTRH
Thermal Shutdown Temperature
TSHTD
THYS(SHTD)
Thermal Shutdown Hysteresis
110
°C
Temperature Rising
160
°C
Temperature Falling
25
°C
c: Charge current is min of 90mA or ISET
2: Charge current is min of 450mA or ISET
3: ISET (mA) = 495 / (RISET (kΩ) - 0.036)
f: TPRECONDITION = TNORMAL / 3 (typ)
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ACT3780
Rev 8, 09-Jul-13
FUNCTIONAL BLOCK DIAGRAM
Body
Control
(Optional)
AC Adaptor
ACT3780
CHG_IN
SYS
System Supply
USB
Body
Control
BAT
ACIN
+
CURRENT SENSE
EN
VOLTAGE SENSE
PRECONDITION
REF
CHGLEV
VTHH
TH
VTHL
nBLV1
nBLV2
+
–
+
–
Thermal
Shutdown
nACOK
System and
Charger Control
ISET
nSTAT3
nSTAT2
DCCC
nSTAT1
BTR
THERMAL
REGULATION
EP
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110°C
G
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Copyright © 2013 Active-Semi, Inc.
ACT3780
Rev 8, 09-Jul-13
when CHGLEV is driven to a logic-high, or to 90mA,
when CHGLEV is driven to a logic-low. This
functionality provides simple means of
implementing a solution that operates within the
current-capability limitations of the USB port while
taking advantage of the high output current
capability of AC adapters. For more information
about the ACIN input, see the ACIN and CHGLEV
Inputs section.
FUNCTIONAL DESCRIPTION
The ACT3780 is a complete battery-charging and
system power management solution for portable
hand-held equipment using single-cell Lithiumbased batteries. The ACT3780 incorporates ActiveSemi's patent-pending ActivePath architecture
which automatically selects the best available input
supply for the system, and additionally features a
complete, high-accuracy (±0.5%), thermally
regulated, Full-Featured single cell linear Li+
charger with an integrated 12V power MOSFET.
Dual-Function MOSFET (Q2)
Q2 is a dual-function power MOSFET, that serves
both as a low-resistance (50mΩ) switch that
supplies the load current requirements of the
system from the battery when no input supply is
present or the system demands more current than
the input can provide.
ActivePath Architecture
Active-semi's proprietary ActivePath architecture
performs three important functions:
System Configuration Optimization
Current-Limits and Charge-Current
Programming
Depending upon the state of the input supply,
ActivePath automatically optimizes the power
system configuration. If the input supply is
present, ActivePath powers the system in parallel
with the battery, so that both system power and
charge current can be independently managed to
ensure that system power requirements are
satisfied, the battery can charge as quickly as
possible, and to ensure that the total system current
does not exceed the capability of the input supply. If
the input supply is not present, then ActivePath
automatically configures the system to draw
power from the battery. Finally, if the system
current requirement exceeds the capability of the
input supply, ActivePath automatically configures
the battery to support the load in parallel with the
input supply, to ensure maximum supply
capability to the load under peak-power
consumption conditions.
ACT3780 provides a flexible current programming
scheme that combines the convenience of internal
charge current programming with the flexibility of
resistor-based charge current programming.
Current limits and charge current programming are
managed as a function of the ACIN and CHGLEV
pins, in combination with RISET, the resistance
connected to the ISET pin.
ACIN and CHGLEV Inputs
ACIN is a logic input that configures the current-limit
of input transistor (Q1) as well as that of the battery
charger. ACIN features an logic input threshold, so
that the input voltage detection threshold may be
adjusted with a simple resistive voltage divider. This
input also allows a simple, low-cost dual-input
charger switch to be implemented with just a few,
low-cost components. As shown in the Functional
Block Diagram.
Input MOSFET Power (Q1)
At the input of the ACT3780's ActivePath circuit is
Q1, an integrated 12V power MOSFET. Q1 is part
of an internal low-dropout linear regulator that
regulates the system voltage (VSYS) to 4.6V,
protecting the system from high-voltage input
supplies. Q1 includes several features that can be
used to limit the total current drawn from the input
supply.
When ACIN is driven to a logic high, the ActivePath
operates in “AC-Mode” and the charger charges at
the current programmed by RISET,
ISET(mA) = 495 / (RISET(kΩ) - 0.036)
When ACIN is driven to a logic-low, the ActivePath
circuitry operates in “USB-Mode”, which enforces a
maximum charge current setting of 450mA, if
CHGLEV is driven to a logic-high, or 90mA, if
CHGLEV is driven to a logic-low.
ACIN's current limit is determined primarily by the
ACIN input, Q1 operates in “AC-Mode” when ACIN
is driven to a logic-high, and Q1 operates in “USBMode” when driven to a logic-low. When operating
in “AC-Mode”, Q1's internal current limit is
programmed to 2.5A. When operating in “USBMode”, Q1's current limit is set to either 450mA,
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ACT3780
Rev 8, 09-Jul-13
The ACT3780's charge current
summarized in the table below:
settings
resistance is monitored by comparing the voltage at
TH to the internal VTHH and VTHL thresholds of 0.5V
and 2.5V, respectively. When VTH > VTHL or VTH < VTHH
charging and the charge timers are suspended. When
VTH returns to the normal range, charging and the
charge timers resume.
are
Table 1:
ACIN and CHGLEV Inputs Table
ACIN
CHGLEV
Fast Charge Current
High
High
ISET (mA) = 495 / (RISET (kΩ) - 0.036)
High
Low
0.5 × ISET
Low
High
Min (450mA, ISET )
Low
Low
Min (90mA, ISET )
The net resistance from TH to G required to cross
the threshold is given by:
100µA × RNOM × kHOT = 0.5V → RNOM × kHOT = 5kΩ
100µA × RNOM × kCOLD = 2.5V → RNOM × kCOLD = 25kΩ
where RNOM is the nominal thermistor resistance at
room temperature, and kHOT and kCOLD are the ratios
of the thermistor's resistance at the desired hot and
cold thresholds, respectively.
Note that the actual charging current may be limited
to a current that is lower than the programmed fastcharge current due to the ACT3780’s internal
thermal regulation loop. See the Thermal
Regulation and Protection section for more
information.
Figure 1:
Simple Configuration
Dynamic Charge Current Control (DCCC)
The ACT3780's ActivePath Charger features
Dynamic Charge Current Control (DCCC) circuitry,
which continuously monitors the input supply to
prevent input overload conditions. DCCC reduces the
charge current when the SYS voltage decreases to
VDCCC and stops charging when SYS drops below
VDCCC by 1.5% (typical).
The DCCC voltage threshold is programmed by
connecting a resistor from DCCC to GA according
to the following equation:
VDCCC = 2 × (IDCCC × RDCCC )
(2)
Design Procedure
Where RDCCC is the value of the external resistor,
and IDCCC (100µA typical) is the value of the current
sourced from DCCC.
When designing with thermistors it is important to
keep in mind that their nonlinear behavior typically
allows one to directly control no more than one
threshold at a time. As a result, the design
procedure can change depending on which
threshold is most critical for a given application.
Given the tolerances of the RDCCC and IDCCC ,the
DCCC voltage threshold should be programmed to
be no less than 3.3V to prevent triggering the
UVLO, and to be no larger than 4.4V to prevent
engaging DCCC prematurely. A 19.1k (1%), or
18.7k (1%) resistor for RDCCC is recommended.
Most application requirements can be solved using
one of three cases,
Battery Temperature Monitoring
1) Simple solution
The ACT3780 continuously monitors the
temperature of the battery pack by sensing the
resistance of its thermistor, and suspends charging
if the temperature of the battery pack exceeds the
safety limits.
2) Fix VTHH, accept the resulting VTHL
3) Fix VTHL, accept the resulting VTHH
The ACT3780 was designed to achieve an
operating temperature range that is suitable for
most applications with very little design effort. The
simple solution is often found to provide reasonable
results and should always be used first, then the
design procedure may proceed to one of the other
solutions if necessary.
In a typical application, shown in Figure 1, the TH
pin is connected to the battery pack's thermistor
input. The ACT3780 injects a 100µA current out of the
TH pin into the thermistor, so that the thermistor
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ACT3780
Rev 8, 09-Jul-13
In each design example, we refer to the Vishay
NTHS series of NTCs, and more specifically those
which follow a "curve 2" characteristic. For more
information on these NTCs, as well as access to the
resistance/temperature characteristic tables referred
to in the example, please refer to the Vishay website
at http://www.vishay.com/thermistors.
Simple Solution
The ACT3780 was designed to accommodate most
requirements with very little design effort, but also
provides flexibility when additional control over a
design is required. Initial thermistor selection is
accomplished by choosing one that best meets the
following requirements:
RNOM = 5kΩ/kHOT, and
(VTHH/ITH) = kHOT(@40°C) × RNOM + R
R = (VTHH/ITH) - kHOT(@40°C) × RNOM
R = (0.5V/100µA) - 0.5758 × 6.8kΩ
Finally,
R = 5kΩ - 3.9kΩ = 1.1kΩ
This result shows that adding 1.1kΩ in series with
the thermistor sets the net resistance from TH to G
to be 0.5V at 40°C, satisfying VTHH at the correct
temperature. Adding this resistance, however, also
impacts the lower temperature limit as follows:
VTHL/ITH = kCOLD(@TC) × RNOM + R
kCOLD(@TC) = (VTHL/ITH - R)/RNOM
Finally,
RNOM = 25kΩ/kCOLD
where kHOT and kCOLD for a given thermistor can be
found on its characteristic tables.
Taking a 0°C to 40°C application using a "curve 2"
NTC for this example, from the characteristic tables
one finds that kHOT and kCOLD are 0.5758 and 2.816,
respectively, and the RNOM that most closely
satisfies these requirements is therefore around
8.8kΩ. Selecting 10kΩ as the nearest standard
value, calculate kCOLD and kHOT as:
kCOLD(@TC) = (25kΩ - 1.1kΩ)/6.8kΩ = 3.51
Reviewing the characteristic curves, the lower
threshold is found to move to -5°C, a change of only
1°C. As a result, the system satisfies the upper
threshold of 40°C with an operating temperature
range of -5°C to 40°C, vs. our design target of 0°C
to 40°C. It is informative to highlight that due to the
NTC behavior of the thermistor, the relative impact
on the lower threshold is significantly smaller than
the impact on the upper threshold.
kCOLD = VTHL/(ITH × RNOM) = 2.5V/(100µA × 10kΩ) = 2.5
kHOT = VTHH/(ITH × RNOM) = 0.5V/(100µA × 10kΩ) = 0.5
Identifying these values on the curve 2
characteristic tables indicates that the resulting
operating temperature range is 2°C to 44°C, vs. the
design goal of 0°C to 40°C. This example
demonstrates that one can satisfy common
operating temperature ranges with very little design
effort.
Fix VTHL
Fix VTHH
Following the same example as above, the
"unadjusted" results yield an operating temperature
range of -6°C to 33°C vs. the design goal of 0°C to
40°C. In applications that favor VTHH over VTHL,
however, one can control the voltage present at TH
at low temperatures by connecting a resistor in
parallel with ITH. The desired resistance can be
found using the following equation:
(ITH + (VCHG_IN - VTHL)/R) × kCOLD(@0°C) × RNOM = VTHL
For demonstration purposes, supposing that we
had selected the next closest standard thermistor
value of 6.8kΩ in the example above, we would
have obtained the following results:
Rearranging yields
kCOLD = VTHL/(ITH × RNOM) = 2.5V/(100µA × 6.8kΩ) = 3.67
R = 82kΩ
kHOT = VTHH/(ITH × RNOM) = 0.5V/(100µA × 6.8kΩ) = 0.74
Adding 82kΩ in parallel with the current source
increases the net
current flowing into the
thermistor, thus increasing the voltage at TH.
Adding this resistance, however, also impacts the
upper temperature limit:
which, according to the characteristic tables would
have resulted in an operating temperature range of
-6°C to 33°C vs. the design goal of 0°C to 40°C.
In this case, one can add resistance in series with
the thermistor to shift the range upwards, using the
following equation:
Innovative PowerTM
R = (VCHG_IN - VTHL)/(VTHL/(kCOLD(@0°C) × RNOM) - ITH)
R = (5V - 2.5V)/(2.5V/(2.816 × 6.8kΩ) - 100µA)
VTHH = (ITH + (VCHG_IN - VTHH)/R) × kHOT(@40°C) × RNOM
Rearranging yields,
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ACT3780
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kHOT(@TC) = VTHH/(RNOM × (ITH + (VCHG_IN - VTHH)/R))
automatically restart.
kHOT(@TC) = 0.5V/(6.8kΩ × (100µA + (5V - 0.5V)/82kΩ))
= 0.4748
Charging Safety Timers
Thermal Regulation and Protection
The ACT3780 features an internal thermal
regulation loop that reduces the charging current as
necessary to ensure that the die temperature does
not rise beyond the thermal regulation threshold of
110°C. This feature protects the ACT3780 against
excessive junction temperature and makes the
device more accommodating to aggressive thermal
designs. Note, however, that attention to good
thermal designs is required to achieve the fastest
possible charge time by maximizing charge current.
In order to account for the extended total charge
time resulting from operation in thermal regulation
mode, the charge timeout periods are extended
proportionally to the reduction in charge current.
The conditions that cause the ACT3780 to reduce
charge current in accordance to the internal thermal
regulation loop can be approximated by calculating
the power dissipated in the part.
The ACT3780 features a programmable safety
charging timer by setting an external resistor from
BTR pin to G (RBTR). The time out period is
calculated as shown in Figure 2. The maximum RBTR
should not be larger than 68kΩ.
If the timeout period expires without change
termination, the ACT3780 will jump to EOC state.
If the ACT3780 detects that the charger remains in
precondition for longer than the precondition time
out period (which determined as TNORMAL/3), the
ACT3780 turns off the charger and generates a
FAULT to ensure prevent charging a bad cell.
Figure 2:
TNORMAL vs. RBTR
190
TNORMAL (Min)
Reviewing the characteristic curves, the upper
threshold is found to move to 45°C, a change of
about 14°C. Adding the parallel resistance has
allowed us to achieve our desired lower threshold of
0°C with an operating temperature range of 0°C to
45°C, vs. our design target of 0°C to 40°C.
160
130
100
The ACT3780 also features thermal shutdown for
further protection. When the device temperature
exceeds 160°C, the device will automatically turn
off to prevent the IC from damage. After the die
temperature decreases below 135°C, the IC will
70
30
35
40
45
50
Figure 4:
Fix VTHL Configuration
Fix VTHH Configuration
- 11 -
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60
65
70
RBTR (kΩ)
Figure 3:
Innovative PowerTM
55
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Copyright © 2013 Active-Semi, Inc.
ACT3780
Rev 8, 09-Jul-13
Charging Status Indication
Table 4:
The ACT3780 provides nSTAT1 and nSTAT2
Outputs to indicate the Charging Status of the
charger. These are two open-drain outputs which
sink current went asserted and high-Z otherwise.
These outputs have internal 6mA current limits, and
are capable of directly driving LEDs, without the
need of current-limiting resistors or other external
circuitry, for a visual charge-status indication. To
drive an LED, simply connect the LED between
each pin and an appropriate supply (typically VSYS).
For a logic level indication, simply connect a
resistor from each output to a appropriate voltage
supply. For more details, see table 2 for LED
indication:
nACOK Output Table
Table 2:
Charging Status Indication Table
STATE
nSTAT1
nSTAT2
Precondition
Low
Low
Fast Charge
Low
High
Charge Complete
High
High
Disabled
High
High
Input Floating
High
High
Fault
High
High
Battery Voltage Level Indication
When the battery is being charged, the ACT3780
senses VBAT and features nBLV1 and nBLV2 as
two battery voltage level indicator outputs. These
are two open-drain outputs which sink current
whenever asserted. For logic level indication,
simply connect a resistor from each output to an
appropriate voltage supply. See below table 3 for
more information:
Table 3:
Battery Voltage Level Indication Table
VBAT STATE
nBLV2
nBLV1
VBAT < 2.8V
Low
Low
2.8V ≤ VBAT < 3.6V
Low
High
3.6V ≤ VBAT < 4V
High
Low
4V ≤ VBAT
High
High
CHG_IN Voltage
nACOK
nSTAT3
VUVLO < VCHG_IN < VOVP
Low
X
VCHG_IN > VOVP
High
Low
VCHG_IN < VUVLO
High
High
Over Voltage Protection (OVP)
The ACT3780 provides over voltage protection
function. When the ACT3780 detects the voltage at
CHG_IN pin is greater than 6.9V, it automatically
turns off the Q1 Power FET and turns on the Q2 to
supply the system load from the battery.
nSTAT3 Output
The ACT3780's nSTAT3 output provide a logic level
indication of OVP. This is an open-drain Output
which sinks current whenever VCHG_IN is greater
than 6.9V.
Enable/Disable Input
The ACT3780's EN is used to enable the IC. Driving
this pin to a logic high enables the ACT3780.
Driving EN pin to a logic low forces the device to
enter suspend mode. In suspend mode, if a valid
input is present at CHG_IN pin, Q1 is turned off.
And the system is powered by the battery via Q2.
This feature is designed to limit the power drawn
from the input supply (such as USB in suspend
mode).
CC/CV Regulation Loop
At the core of the ACT3780's battery charger is a
CC/CV regulation loop, which regulates either
current or voltage as necessary to ensure fast and
safe charging of the battery. In a normal charge
cycle, this loop regulates the current to the value
set by the external resistor at the ISET pin.
Charging continues at this current until the battery
cell voltage reaches the termination voltage (default
is 4.2V or 4.1V). At this point the CV loop takes
over, and charge current is allowed to decrease as
necessary to maintain charging at the termination
voltage.
nACOK Output
Enable/Disable Charging
The ACT3780's nACOK output provides a logiclevel indication of the status of the voltage at
CHG_IN. nACOK is an open-drain output which
sinks current when a valid input is applied to
CHG_IN.
The ACT3780's DCCC pin can be used to disable
charging. By floating the DCCC pin, the charger will
be disabled.
Innovative PowerTM
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ACT3780
Rev 8, 09-Jul-13
Figure 5:
Typical Li+ Charge Profile and ACT3780 Charge States
A: PRECONDITION State
B: FAST-CHARGE State
C: TOP-OFF State
D: END-OF-CHARGE State
Charger State-Machine
PRECONDITION State
A new charging cycle begins with the
PRECONDITION state, and operation continues in
this state until VBAT exceeds the Precondition
Threshold Voltage of 2.85V (typ). When operating
in PRECONDITION state, the cell is charged at a
reduced current, 10% of the programmed maximum
fast-charge constant current, ISET. Once VBAT
reaches the Precondition Threshold Voltage the
state machine jumps to the FAST-CHARGE state. If
VBAT does not reach the Precondition Threshold
Voltage before the Precondition Timeout period
TPRECONDITION expires, then a damaged cell is
detected and the state machine jumps to the
TIMEOUT- FAULT State. For the Precondition
Timeout period, see the Charging Safety Timers
section for more information.
FAST-CHARGE State
In FAST-CHARGE state, the ACT3780 charges at
the current programmed by RISET (see the Current
Limits and Charge Current Programming section for
more information). During a normal charge cycle
fast-charge continues in CC mode until VBAT
reaches the charge termination voltage (VTERM), at
which point the ACT3780 charges in TOP-OFF
state. If VBAT does not proceed out of the FASTCHARGE state before the Normal Timeout period
(TNORMAL) expires, then the state machine jumps to
the END-OF-CHARGE state and will re-initiate a
new charge cycle after 2-4ms “relax”.
Innovative PowerTM
TOP-OFF State
In the TOP-OFF state, the cell is charged in
constant-voltage (CV) mode. Charge current
decreases as charging continues. During a normal
charging cycle charging proceeds until the charge
current decreases below the END-OF-CHARGE
(EOC) threshold, defined as 10% of ISET (ACIN =
1) or 4% of ISET (ACIN = 0) . When this happens,
the state-machine terminates the charge cycle and
jumps to the EOC state. If the state-machine does
not jump out of the TOP-OFF state before the TotalCharge Timeout period expires, the state machine
jumps to the EOC state and will re-initiate a new
charge cycle when VBAT falls 175mV(typ) below the
charge termination voltage.
END-OF-CHARGE State
In the END-OF-CHARGE (EOC) state, the
ACT3780 presents a high-impedance to the battery,
allowing the cell to “relax” and minimizes battery
leakage current. The ACT3780 continues to monitor
the cell voltage, however, so that it can re-initiate
charging cycles when VBAT falls 175mV(typ) below
the charge termination voltage.
SUSPEND State
The ACT3780 features an user-selectable suspend
charge mode, which disables the charger but keeps
other circuiting functional. The charger can be put
into suspend mode by driving EN to logic low. Upon
exiting the SUSPEND State, the charge timer is
reset and the state machine jumps to
PRECONDITION state.
- 13 -
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ACT3780
Rev 8, 09-Jul-13
Figure 6:
Charger State Diagram
TEMP NOT OK
ANY STATE
BATTERY REMOVED OR
(VCHGIN < VBAT) OR (VCHGIN < VCHGIN UVLO)
OR (VCHGIN > VOVP) OR
EN = LOW
SUSPEND
TEMP-FAULT
BATTERY REPLACED AND
(VCHGIN > VBAT) AND (VCHGIN > VCHGIN UVLO)
AND (VCHGIN < VOVP) AND
EN = HIGH
TEMP OK
T > TPRECONDITION
TIMEOUT-FAULT
PRECONDITION
VBAT > 2.85V
T > TNORMAL
FAST-CHARGE
VBAT = VTERM
TOP-OFF
IBAT < IEOC OR
T > TNORMAL
END-OF-CHARGE
Innovative PowerTM
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ACT3780
Rev 8, 09-Jul-13
TYPICAL PERFORMANCE CHARACTERISTICS
(VCHG_IN = 5V, RDCCC = 18.7kΩ, TA = 25°C, unless otherwise specified.)
Supply Current vs. CHG_IN Voltage (EN = 0)
Standby Current (mA)
100
80
60
40
20
0
Dropout Operation
4
3
Normal Operation
2
Over-Voltage Operation
1
VBAT = 4.3V
EN = 1
Under-voltage Lockout
0
3
5
7
9
11
3
13
5
7
1
No CHG_IN
CHGLEV = 0
3
4
5
No CHG_IN
VCHG_IN = 5V
3
2
CHGLEV = 0
VBAT = 4V
EN = 0
-40
-20
0
20
40
60
80
100
120
140
Temperature (°C)
Battery Voltage (USB Mode)
Charger Current vs. Battery Voltage (USB Mode)
VBAT Falling
VBAT Rising
200
100
CHG_IN = 5V
ISYS = 0 mA
500mA USB
0
1.0
1.5
2.0
2.5
3.0
3.5
4.0
ACT3780-006
100
ACT3780-005
300
0.5
4
Bat Voltage (V)
400
0
5
1
6
500
Charger Current (mA)
Battery Leakage Current (µA)
2
Charger Current (mA)
BAT Reverse Leakage (µA)
3
ACT3780-004
4
2
13
6
ACT3780-003
5
1
11
BAT Reverse Leakage vs. Temperature
BAT Reverse Leakage vs. Bat Voltage
6
0
9
CHG_IN Voltage (V)
CHG_IN Voltage (V)
0
ACT3780-002
120
Supply Current (µA)
Standby Current vs. CHG_IN Voltage
5
ACT3780-001
140
80
VBAT Falling
60
VBAT Rising
40
20
CHG_IN = 5V
ISYS = 0 mA
100mA USB
0
4.5
0
0.5
Battery Voltage (V)
Innovative PowerTM
1.5
2.0
2.5
3.0
3.5
4.0
4.5
Battery Voltage (V)
- 15 -
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1.0
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Copyright © 2013 Active-Semi, Inc.
ACT3780
Rev 8, 09-Jul-13
TYPICAL PERFORMANCE CHARACTERISTICS
(VCHG_IN = 5V, RDCCC = 18.7kΩ, TA = 25°C, unless otherwise specified.)
Charger Current vs. Battery Voltage (AC Mode)
Pre-Charge Current (mA)
Charger Current (mA)
800
600
VBAT Falling
400
VBAT Rising
200
0
0.0
100
ACIN/CHGLEV = 00
80
ACIN/CHGLEV = 11
60
40
20
0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
-50
0
Battery Voltage (V)
100
150
Battery Regulation Accuracy vs. Temperature
1000
ACIN/CHGLEV = 11
ACT3780-010
VCHG_IN = 5V
VBAT = 3.5V
1.0
ACT3780-009
0.5
800
600
Error (%)
Fast Charge Current (mA)
50
Temperature (°C)
Fast Charge Current vs. Temperature
1200
ACIN/CHGLEV = 01
400
0.0
-0.5
ACIN/CHGLEV = 00
200
0
VCHG_IN = 4.5V
ACIN/CHGLEV = 11
-1.0
-50
0
50
100
150
-40
-15
Temperature (°C)
SYS Output Voltage vs. CHG_IN Voltage
60
85
SYS Voltage vs. SYS Current (DC Input)
ACT3780-012
VCHG_IN = 5.5V
4.60
SYS Voltage (V)
4.6
4.5
ACIN = 0
CHGLEV = 0
4.3
35
4.80
ACT3780-011
4.7
4.4
10
Temperature (°C)
4.8
SYS Voltage (V)
VCHG_IN = 5V
VBAT = 2.5V
ACIN/CHGLEV = 01
ACT3780-008
CHG_IN = 5V
ISYS = 0mA
RISET = 510Ω
1000
Pre-Charge Current vs. Temperature
120
ACT3780-007
1200
4.2
4.40
VCHG_IN = 5V
4.20
4.00
3.80
4.1
ISYS = 10mA
4.0
0
2
4
6
8
10
12
VBAT = 4V
ACIN/CHGLEV = 11
3.60
0
14
- 16 -
Active-Semi Proprietary―For Authorized Recipients and Customers
ActivePathTM is a trademark of Active-Semi.
1000
1500
2000
SYS Current (mA)
CHG_IN Voltage (V)
Innovative PowerTM
500
www.active-semi.com
Copyright © 2013 Active-Semi, Inc.
ACT3780
Rev 8, 09-Jul-13
TYPICAL PERFORMANCE CHARACTERISTICS
(VCHG_IN = 5V, RDCCC = 18.7kΩ, TA = 25°C, unless otherwise specified.)
SYS Voltage vs. SYS Current (USB)
RDSON Q1 vs. Temperature
4.40
4.20
0.5
RDSON Q1 (Ω)
SYS Voltage (V)
4.60
ACT3780-014
0.6
ACT3780-013
4.80
VCHG_IN = 5V - 500mA
4.00
3.80
VCHG_IN = 5V - 100mA
0.4
0.3
0.2
3.60
VCHG_IN = 4.5V
No BAT
0.1
3.40
0
400
800
1200
1600
2000
2400
-40
-15
10
35
60
85
110
SYS Current (mA)
Temperature (°C)
DC Connect with Battery Present
DC Disconnect with Battery Present
CH1
CH2
CH2
0V
0V
Charging
CH3
ACT3780-016
ACT3780-015
CH1
135
Charging
CH3
0mA
0mA
RSYS = 22Ω
VBAT = 3.6V
ACIN/CHGLEV = 11
RSYS = 22Ω
VBAT = 3.6V
ACIN/CHGLEV = 11
CH1: VSYS, 2.00V/div
CH2: VCHG_IN, 5.00V/div
CH3: IBAT, 500mA/div
TIME: 400μs/div
CH1: VSYS, 2.00V/div
CH2: VCHG_IN, 5.00V/div
CH3: IBAT, 500mA/div
TIME: 400µs/div
Battery Connect
ACT3780-017
CH1
CH2
CH3
CH1: VSYS, 2.00V/div
CH2: VBAT, 2.00V/div
CH3: IBAT, 200mA/div
TIME: 400μs/div
Innovative PowerTM
- 17 -
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Copyright © 2013 Active-Semi, Inc.
ACT3780
Rev 8, 09-Jul-13
TYPICAL PERFORMANCE CHARACTERISTICS
(VCHG_IN = 5V, RDCCC = 18.7kΩ, TA = 25°C, unless otherwise specified.)
Charge Current Response vs. CHGLEV
CH1
ACT3780-019
ACT3780-018
CH1
0V
CH2
ACIN = 0
ISYS = 0A
VBAT = 3.6V
Charge Current Response vs. ACIN
RSYS = 22Ω
VBAT = 3.6V
CHGLEV = 1
CH2
CH3
CH3
0mA
CH1: VCHGLEV, 5.00V/div
CH2: VSYS, 1.00V/div
CH3: IBAT, 200mA/div
Innovative PowerTM
CH1: VACIN, 5.00V/div
CH2: VSYS, 1.00V/div
CH3: IBAT, 500mA/div
- 18 -
Active-Semi Proprietary―For Authorized Recipients and Customers
ActivePathTM is a trademark of Active-Semi.
www.active-semi.com
Copyright © 2013 Active-Semi, Inc.
ACT3780
Rev 8, 09-Jul-13
PACKAGE OUTLINE
TQFN44-20 PACKAGE OUTLINE AND DIMENSIONS
D
D/2
SYMBOL
E/2
A
MIN
MAX
A
0.700
0.800
0.028
0.031
A1
0.000
0.050
0.000
0.002
0.008 REF
0.180
0.300
0.039
0.012
D
3.900
4.100
0.154
0.161
E
3.900
4.100
0.154
0.161
D2
2.550
2.80
0.090
0.100
E2
2.550
2.80
0.090
0.100
R
b
0.200 REF
b
L
D2
L
MAX
e
A1
DIMENSION IN
INCHES
MIN
A3
E
A3
DIMENSION IN
MILLIMETERS
K
0.500 BSC
0.300
0.500
0.200 TYP
0.200
---
0.020 BSC
0.012
0.020
0.008 TYP
0.008
---
e
E2
K
R
Active-Semi, Inc. reserves the right to modify the circuitry or specifications without notice. Users should evaluate each
product to make sure that it is suitable for their applications. Active-Semi products are not intended or authorized for use
as critical components in life-support devices or systems. Active-Semi, Inc. does not assume any liability arising out of
the use of any product or circuit described in this datasheet, nor does it convey any patent license.
Active-Semi and its logo are trademarks of Active-Semi, Inc. For more information on this and other products, contact
sales@active-semi.com or visit http://www.active-semi.com.
is a registered trademark of Active-Semi.
Innovative PowerTM
- 19 -
Active-Semi Proprietary―For Authorized Recipients and Customers
ActivePathTM is a trademark of Active-Semi.
www.active-semi.com
Copyright © 2013 Active-Semi, Inc.