SC804IMLTRT [SEMTECH]
Fully Integrated Lithium-Ion Battery Charger System with Timer; 完全集成的锂离子电池充电器系统具有定时器
| 型号： | SC804IMLTRT |
| 厂家： | 
SEMTECH CORPORATION |
| 描述： | Fully Integrated Lithium-Ion Battery Charger System with Timer |
| 文件： | 总21页 (文件大小：537K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
SC804
Fully Integrated Lithium-Ion Battery
Charger System with Timer
POWER MANAGEMENT
Description
Features
ꢀFully integrated charger with FET pass transistor,
reverse-blocking diode, sense resistor, timer, and
thermal protection
The SC804 is a fully integrated full-feature, single cell
constant-current/constant-voltage (CC/CV) Lithium-Ion
battery charger. With an integrated timer and complete
charge control algorithm, the SC804 is ideal for stand-
ꢀBattery voltage controlled to 1% accuracy
alone charger applications.
The SC804 contains
ꢀProgrammable pre charge, fast charge & termination
current over wide range, with analog current control
reference input for design flexibility
programmable pre-charge, fast-charge and termination
current settings. The SC804 can be programmed to
terminate charging based on the output current or the
time-out of the programmable timer. The fast charge
current is typically set with an external resistor, but it can
also be adjusted by applying an analog voltage to the AFC
pin. This feature allows use of a micro controller to set
charging current via a DAC output.
ꢀUp to 1.5A continuous charge current
ꢀInput voltage range from 3V to 14V
ꢀSoft-start reduces start-of-charge adapter
load transients
ꢀNTC thermistor sense input and adjustable cold
temperature threshold
The SC804’s 14V input voltage range eliminates the
need for additional protection circuitry required by other
ꢀAdjustable 2 - 6 hour programmable charge timer
5V chargers to protect against faulty adapters. The ꢀ0.1μA battery drain current in shutdown and monitor
SC804 also incorporates an under-voltage lockout falling
threshold of 3V so that charging will continue if the input
supply goes into a current-limited mode.
modes
ꢀSmall 4mm x 4mm 16 lead MLPQ package
ꢀOver-current protection in all modes
ꢀOver-voltage protection
Reference ground and battery sense inputs are provided
to eliminate voltage drops during charging due to high
charging currents.
ꢀRemote Kelvin sensing at the battery terminals
ꢀStatus indicators for charger-present, charger-active,
over-voltage fault, and error notification
The output voltage to the battery is controlled to within 1%
of the programmed voltage. The SC804 can also function Applications
as a general purpose current source or as a current
ꢀHandheld computers
ꢀDigital cameras
ꢀProgrammable current
source
ꢀCellular phones
ꢀPDAs
ꢀHandheld meters
ꢀCharging stations
Typical Application Circuit
source for charging nickel-cadmium (NiCd) and nickel-
metal-hydride (NiMH) batteries.
Typical Application Circuit
Charger VIN
14
11
VCC
13
CPB
10
12
2
OV_FLT
OVPB
IPRGM
NTC
CHRGB
RTIM
CTO
Red
Green
3
7
4
8
6
5
R3
C1
2.2 μF
1
ITERM
FLTB
BSEN
VOUT
VOUT
AFC
RT
NTC
16
15
9
R5
R6
R1
R2
GND
C2
RGND
2.2μF
Battery
SC804
R4
ERROR
DAC ISET
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SC804
POWER MANAGEMENT
Absolute Maximum Ratings
Exceeding the specifications below may result in permanent damage to the device or device malfunction. Operation outside of the parameters specified in the
Electrical Characteristics section is not implied.
Parameter
Symbol
Maximum
Units
VCC, CTO, NTC to GND
-0.3 to 14.0
V
VOUT, BSEN, RTIM, AFC, IPRGM, CPB, CHRGB, OVPB,
ITERM, FLTB, to GND
-0.3 to +6.0
V
RGND to GND
-0.3 to 0.3
V
A
VOUT Output Current
IVOUT
Pd
1.5
Power Dissipation MLP (Derate 20mW/°C above 85°C)
Thermal Impedance, Junction to Ambient(1)
Junction Temperature
2
48
W
θJA
°C/W
°C
TJ
150
Operating Ambient Temperature Range
IR Reflow Temperature
TA
-40 to +85
260
°C
TLEAD
TSTG
°C
Storage Temperature Range
VOUT short to GND
-65 to 150
Continuous
2
°C
ESD Protection Level(2)
V ESD
kV
Notes:
1) Calculated from package in still air, mounted to 3” x 4.5”, 4 layer FR4 PCB with thermal vias under the exposed pad per JESD51 standards.
2) Tested according to JEDEC standard JESD22-A114-B.
Electrical Characteristics
Unless otherwise noted: VCC = 4.75V - 5.25V. Typical values are at TA = 25°C Min and Max are for -40°C < TA < +85°C unless noted.
Parameter
Symbol
VCCOP
Conditions
Min
4.2
3.8
Typ
5.0
4.0
Max
6.1(1)
4.2
Units
Operating Voltage
V
V
VCC UVLO Rising
Threshold
Charging begins when
threshold is exceeded
VTUVLOR
VCC UVLO Falling
Threshold
Charging continues until
threshold is reached
VTUVLOF
VTOVPR
2.8
6.5
3.0
6.8
3.2
V
V
VCC OVP Rising
Threshold
7.25
VCC OVP Falling
Threshold
VTOVPF
VTOVPH
ICCDIS
6.1
6.5
350
1.9
6.85
600
V
VCC OVP Hysteresis
200
mV
Shutdown Mode - CHRGB, CPB,
OVPB, FLTB off NTC = 0V
Operating Current
mA
Charging Mode - CHRGB, CPB,
OVPB, FLTB off NTC = 2.5V
ICCCHG
2.0
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SC804
POWER MANAGEMENT
Electrical Characteristics (Cont.)
Parameter
Symbol
Conditions
Min
Typ
Max
Units
Battery Leakage Current
(VOUT and BSEN)
VCC = 0V,
VOUT = BSEN = 4.5V
ILEAKBAT
0.1
2
μA
Regulated Constant
Voltage
VCV
0°C ≤ TJ ≤ 125°C
4.16
22
4.20
30
4.24
38
V
RGND Output Accuracy
VOUT = VOUTNOM
+
VRGND
RGND - GND = 30mV
mV
∆RGND
RGND Current
IRGND
IPREQ
RGND = 0V
35
μA
Battery Pre-Charge
Current
RITERM = 499Ω, 0°C ≤ TJ ≤ 125°C
270
270
740
300
330
330
860
mA
Battery Termination
Current
ITERM
RITERM = 499Ω, 0°C ≤ TJ ≤ 125°C
300
800
mA
mA
RPRGM = 1.87kΩ, VOUT = 3.8V
0°C ≤ TJ ≤ 125°C
Battery Fast-Charge
Current
IFAST
RPRGM = 1.87kΩ, V(AFC) = 0.75V
0°C ≤ TJ ≤ 125°C
AFC DAC
Fast-Charge Current
IDACADJ
360
400
1
440
mA
V
VCC - VAFC > VTAFC disables
Analog Fast Charge
AFC Enable/Disable
Threshold
VTAFC
ITERM Regulated
Voltage
VITERM
VIPRGM
VTPreQ
VTReQ
TOT
1.4
1.4
2.8
60
1.5
1.5
1.6
1.6
3.0
140
V
V
IPROG Regulated
Voltage
VBAT Pre-Charge
Threshold
0°C ≤ TJ ≤ 125°C
VCV - VBSEN, 0°C ≤ TA ≤ 85°C
Hysteresis = 10°C
2.9
V
VBAT Recharge Threshold
100
150
mV
°C
Over-Temperature
Shutdown
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SC804
POWER MANAGEMENT
Electrical Characteristics (Cont.)
Parameter
Symbol
Conditions
Min
Typ
Max
Units
VTNTCDIS
SC804 Disabled
0.3
0.6
0.8
V
NTC Hot VTH
Applies to falling threshold
4.3V ≤ VCC ≤ 6.5V
% of
VCC
29
30
31
VTNTCH
at VCC = 5V
1.45
73.4
3.67
1.50
74.4
3.72
1.55
75.4
3.77
V
NTC Cold VTH, VCTO = 0V
Applies to rising threshold
4.3V ≤ VCC ≤ 6.5V
% of
VCC
VTNTCC
at VCC = 5V
V
NTC Hot & Cold VTNTCx
hysteresis
(VTNTCx Rising - VTNTCx Falling)
NTC Thresholds
VTNTCHYS
50
mV
Applies to internal NTC
thresholds
CTO Voltage (Adjustable NTC
Cold Rising Threshold) Setting
Range(2), -40°C ≤ TA ≤ 25°C
(NTC Cold Rising Threshold is
VTNTCC when CTO tied to GND)
% of
VCC
50
90
70
VCTO
Threshold Error(3),
-40°C ≤ TA ≤ 25°C
-70
mV
mV
Internal hysteresis on CTO (VCTO
Rising - VCTO Falling)
Applies to externally set NTC
cold threshold
VTCTOHYS
50
Adjust Mode
BSEN Voltage
3.5V ≤ VOUT ≤ VCC - 150mV
0°C ≤ TJ ≤ 125°C
VBSEN-ADJ
3.072
150
3.11
3.134
400
V
Adjust Mode Enable
Voltage, VOUT-BSEN
VADJEN
3.5V ≤ VOUT ≤ VCC - 150mV
3.5V ≤ VOUT ≤ VCC - 150mV
mV
mV
Adjust Mode Disable
Voltage, VOUT-BSEN
VADJDIS
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SC804
POWER MANAGEMENT
Electrical Characteristics (Cont.)
Parameter
Symbol
Conditions
Min
Typ
Max
Units
External RTIM
Regulation Voltage
VRTIM
RRTIM = 37.4kΩ
1.4
1.5
1.6
V
VRTIM ≤ VTTIMER
Timer Disable Threshold
Internal Timer Select
VTTIMER
VTINTTS
TPreQF
0.65
0.85
1.1
V
V
disables internal timer
VCC-VRTIM > VTINTTS
selects internal timer
RRTIM = 37.4kΩ
RTIM pulled to VCC
RRTIM = 37.4kΩ
-20%
-35%
53
45
+20%
+35%
Pre-Charge Fault Time-Out
min
hr
Complete Charge
Time-Out
-20%
-35%
3.5
3.0
+20%
+35%
TQCOMP
RTIM pulled to VCC
CHRGB On
CHRGB Off
CPB On
VCHRGB
ICHRGB
VCPB
ICPB
Load = 5mA
Leakage Current, V = 5V
Load = 5mA
0.5
0.5
0.5
0.5
1
1
1
1
1
1
1
1
V
μA
V
CPB Off
Leakage Current, V = 5V
Load = 5mA
μA
V
OVPB On
OVPB Off
FLTB On
VOVPB
IOVPB
VFLTB
IFLTB
Leakage Current, V = 5V
Load = 5mA
μA
V
FLTB Off
Leakage Current, V = 5V
μA
Notes:
1) VCCOP Max is the “Maximum Vsupply” as defined in EIA/JEDEC Standard No. 78, paragraph 2.11.
2) The absolute voltage on CTO must not exceed 6.0V to ensure normal operation.
3) The threshold error is tested at VCTO min and max only.
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SC804
POWER MANAGEMENT
Pin Configuration
Ordering Information
DEVICE
SC804IMLTRT(1)
SC804EVB
PACKAGE
MLPQ -16(2)
16
15
14
13
RTIM
BSEN
CTO
1
2
3
4
12
11
10
9
Evaluation Board2(
)
TOP VIEW
CPB
Notes:
CHRGB
IPRGM
ITERM
1) Available in tape and reel packaging only. A reel contains 3000
devices.
T
AFC
2) Available in lead-free packaging only. This product is fully WEEE
and RoHS compliant.
5
6
7
8
MLPQ16: 4X4 16 LEAD
Pin Descriptions
Pin Desciptions
Pin #
Pin Name Pin Function
1
BSEN
CTO
Battery voltage sense. Connect to battery positive terminal for Kelvin voltage sensing, VOUT otherwise. Do not leave open.
Cold Temperature Offset. Adjustable NTC input high voltage (cold temperature) threshold. When the pin is
2
connected to GND the NTC high voltage threshold defaults to VTNTCC×VVCC
.
3
4
5
6
IPRGM
ITERM
RGND
GND
Charger current program pin for fast-charge mode. Requires a resistor to GND to program fast-charge current.
Charger termination current program pin. Requires a resistor to GND to program pre-charge and termination current.
Reference ground. Connect to battery’s negative terminal for Kelvin voltage sensing, GND otherwise. Do not leave open.
Ground.
Input for battery NTC thermistor network. Voltage between VTNTCH×VVCC, normally the hot threshold, and the
CTO voltage (VTNTCC×VVCC if CTO is tied to GND), normally the cold threshold, enables charging. Voltages outside
this range suspend charging and drive FLTB pin active (low). Voltage below VTNTCDIS (nominally 0.6V) disables the
SC804 and resets the charge timer (with FLTB pin inactive).
7
NTC
8
9
FLTB
AFC
Open drain fault indicator. Active low when a fault condition occurs.
Analog Fast Charge input. Connect to a DAC for analog control of fast charge current level, connect to VCC to
disable this feature. Do not leave open.
Open drain charge status indicator. Active low when the charger is on and the output current exceeds
the termination current setting, high impedance when IVOUT < ITERM.
10
11
12
CHRGB
CPB
Open drain charger-present indicator. Active low when VCC exceeds UVLO.
Programmable timer input pin. Connect to VCC to select the default time-out of 3 hours, connect to GND
to disable timer, or connect an external resistor to GND to program the time-out period.
RTIM
13
14
15
16
OVPB
VCC
Open drain over-voltage indicator. Active low when an input over-voltage fault occurs.
Input supply pin. Connect to adapter power.
VOUT
VOUT
Charger output. Connect to battery.
Charger output. Connect to battery.
THERMAL
PAD
Thermal-conduction pad on bottom of the package. Solder directly to the ground plane with multiple
thermal vias to all other ground planes.
T
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SC804
POWER MANAGEMENT
Block Diagram
14
VCC
1
9
BSEN
AFC
V
CV (VBSEN-ADJ in Adj. Mode)
Reference
Voltages
Fast-Charge Ref
Pre- Charge Ref
VTNTCC VTNTCH
5
RGND
Pre-Charge On
Fast-Charge On
Over-Temp
Under-Voltage
Over-Voltage
Cold
Threshold
Offset
VOUT
VOUT
15
16
2
6
7
CTO
GND
NTC
Control
Timer
V
ITERM
NTC
Interface
ITERM
IPRGM
4
3
RTIM 12
V
IPRGM
10
11
8
CHRGB
CPB
FLTB
OVPB
13
Figure 1 - SC804 Functional Block Diagram
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SC804
POWER MANAGEMENT
Applications Information
General Operation
Fast-Charge Mode (CC)
The SC804 can be configured independently with respect
to fast-charge and termination current, output voltage,
and timing, depending on the application. A typical
charging cycle is described below. Details on alternative
applications and output programmability are covered in
the individual sections.
The fast-charge CC (Constant Current) mode is active when
the battery voltage is above VTPreQ and less than VCV. The
fast-charge current can be set to a maximum of 1.5A and
is selected by the program resistor on the IPRGM pin. The
voltage on this pin will represent the current through the
battery, enabling a microprocessor via an analog-to-digital
converter (ADC) to monitor battery current by sensing the
voltage on the IPRGM pin. The equation to set the fast-
charge current is given by:
The charging cycle begins when the power adapter is
connected to the device. The SC804 performs glitch
filtering on the VCC input and initiates a charge cycle when
VVCC is greater than the under-voltage lockout (UVLO) rising
threshold voltage. If the battery voltage is less than the
pre-charge threshold level, the SC804 will output the pre-
charge current. Once the pre-charge threshold voltage
is exceeded, the SC804 enters fast-charge constant
VIPRGM_Typ
× 1000
FCI =
RIPRGM
current (CC) mode. When the battery voltage reaches its The superior fast-charge current accuracy of the SC804
final value, the charger enters the constant voltage (CV) is obtained by use of a patented* polarity-switched (i.e.,
mode. In this mode the output current decreases as the chopped) current sense amplifier to nullify current mea-
battery continues to charge until the termination current surement offset errors.
level is reached. The CHRGB output turns off when IOUT
Compliance with the absolute maximum output current
drops below the termination current. If the charge timer
IVOUTMAX, allowing for current regulation tolerance, requires
that RIPRGM be no smaller than 1.05kΩ nominal. RIPRGM
can be as large as 11.5kΩ, for a nominal FCI as small
as 130mA, but must exceed PCI by at least 80mA. Note
is active, the SC804 continues to hold the battery in CV
charge mode until the timer expires. When the timer
expires the charger enters the monitor mode where the
output remains off until the voltage at VOUT drops by
that for a given program resistor the current through
VTReQ. At this point a new charge cycle is initiated.
the battery in CV mode can be determined by replacing
VIPRGM_Typ with the actual voltage on the IPRGM pin in the
above equation. The CC current can also be modified by
applying an analog voltage to the AFC pin as described
Pre-Charge Mode
Pre-charge mode is automatically enabled whenever
below.
the battery voltage is below the pre-charge threshold
voltage, VTPreQ. It is used to limit the power dissipation and
precondition the battery for fast charging. The pre-charge
Analog Fast Charge (AFC Pin)
current value is determined by the resistor on the ITERM
Many applications require more than one current setting
pin. The pre-charge current is programmable from 50mA
for fast-charge. This behavior is obtained in the SC804
to 350mA. The equation to select the pre-charge current
using the AFC function. When the AFC pin is connected
is given by:
to VCC the device behaves as described in the previous
section. When the AFC pin is driven by an analog voltage
between 0V and (VVCC-1.0)V, the SC804 automatically uses
this pin voltage to set the maximum fast-charge current
according to the following equation:
VITERM_Typ
PCI =
× 100
RITERM
WhereVITERM_Typ designatesthetypicalvalueofVITERM. When
the timer is enabled there is also a maximum allowed pre-
charge duration. If the pre-charge time exceeds 25% of
the total charge cycle the charger will turn off due to a
pre-charge fault. This fault is cleared when VCC is toggled
VAFC
FCI =
× 1000
RIPRGM
or the output voltage rises above VTPreQ
.
*US Patent 6,836,095.
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SC804
POWER MANAGEMENT
Applications Information
Charge Timer
This adjustment to the fast charge current is obtained
by replacing the fixed VIPRGM reference voltage with the
AFC voltage. (Note that AFC voltages above VIPRGM will
produce IVOUT exceeding that programmed as per the Fast-
Charge Mode (CC) section.) For any applied AFC voltage,
FCI must not drop below 130mA, and FCI must always
remain at least 80mA greater than PCI.
The timer on the SC804 has two functions: to protect in
the event of a faulty battery and to maximize charging
capacity. The RTIM pin is connected to VCC to select the
internal timer, and to GND to disable the timer.
Connecting a resistor between RTIM and GND will program
the total charge time according to the following equation:
RRTIM
3
1
Termination Current
Charge time =
×
(
)
3600
Once the battery voltage reaches VCV the SC804 will
transition from constant current mode to constant voltage
mode. The current through the battery will decrease while
the voltage remains constant as the battery becomes fully
charged. When the current falls below the programmed
termination current set by the termination resistor
connected to the ITERM pin, the SC804 will disable
CHRGB. If the timer is enabled the output will continue
to float-charge in CV mode until the timer expires. If the
timer is disabled, the output will turn off as soon as the
termination current level is reached. The equation to set
the termination current is given by:
with charge time expressed in hours. The timer is
programmable over the range of 2 to 6 hours. The internal
timer selection results in a charge time of 3 hours. The
SC804 will automatically turn off the output when the
charge timer times out.
NTC Interface
The NTC pin provides an interface to a battery pack
Negative Temperature Coefficient (NTC) thermistor. The
typical NTC network has a fixed resistor from VCC to the
NTC pin, and the battery pack NTC thermistor connected
from the NTC pin to ground. In this configuration, an
increasing battery temperature produces a decreasing
NTC pin voltage, and a decreasing battery temperature
produces an increasing NTC pin voltage.
VITERM_Typ
× 100
ITERM =
RITERM
This configuration is shown in the typical application
schematic on page 1 of this datasheet. When the NTC
voltage from the divider is greater than the high (cold)
threshold or less than the low (hot) threshold, the SC804
suspends the charge cycle by turning off the output,
halting (but not resetting) the charge timer, and indicating
a fault on the FLTB pin. Hysteresis is included for both
high and low NTC thresholds to avoid chatter at the NTC
trip points. When the NTC pin voltage returns to the valid
range, the SC804 automatically resumes the charge cycle.
The charge timer will time-out when the SC804 output on-
time exceeds the timer setting regardless of how long it
has been disabled due to the NTC temperature.
ITERM can be programmed to be as high as 300mA or as
low as 50mA, though accuracy is not guaranteed below
100mA. ITERM must be programmed to be less than FCI
for correct operation of the charge cycle.
Monitor Mode
When a charge cycle is complete, the SC804 output turns
off and the device enters monitor mode. If the voltage
of the battery falls below the recharge threshold (VCV
- VReQ), the charger will clear the charge timer and re-
initiate a charge cycle. The maximum current drain of the
battery during monitor mode will be no more than 1μA
over temperature. The status of the charger output as a
function of the timer and IOUT is tabulated below.
An input voltage between VTNTCH×VVCC and the CTO input
voltage VCTO (VTNTCC×V if CTO is tied to GND) enables
charging. An input voVltCaC ge outside this range suspends
charging and drives FLTB pin active (low). The internal
NTC thresholds of VTNTCH and VTNTCC were designed to
Timer
Iout
N/A
Output State
T < Timeout
T > Timeout
Disabled
On
Off
Off
N/A
< Itermination
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SC804
POWER MANAGEMENT
Applications Information (Cont.)
work with standard thermistors available from numerous Step 1: Select R3. For the normal (NTC thermistor to
vendors.
ground) configuration, solve the NTC network voltage
divider for R3 to place the NTC voltage at 0.3×VCC when
NTC pin voltage below VTNTCDIS (nominally 0.6V) disables
the SC804 and resets the charge timer (with the FLTB pin
inactive). The NTC pin can be pulled down to ground by
an external n-channel FET transistor or processor GPIO to
disable or reset the SC804.
RT = RHOT
.
VCC × RHOT
R3 + RHOT
0.3 × VCC =
or R3 = 2.333×RHOT = 13.624kΩ exactly. The closest 1%
standard nominal value is R3 = 13.7kΩ.
Note that the response of the SC804 to NTC pin voltage
above the high threshold and below the low threshold
is the same. Thus it is possible to configure the NTC
network with the battery pack thermistor between NTC
and VCC, and a fixed resistor between NTC and ground.
This configuration may be useful if it is desired to reset the
charge timer (and the CHRGB output) when the battery
pack is removed (so the fixed resistor pulls the NTC pin to
ground) while VCC is present.
Step 2: Verify acceptable thermistor self heating. In
general, lower values of RT provide more noise immunity
for the NTC voltage, but at the expense of bias current
from the input adapter and power dissipation in the NTC
network. The dissipation constant is the power rating of
the thermistor resulting in a 1°C self heating error. The
greatest self-heating occurs at low thermistor resistance
(at high temperature). Since temperature sensing
accuracy matters only at the charging temperature range
thresholds, self heating is assessed only at the worst case
high temperature threshold of +40°C.
Cold Temperature Offset (CTO)
The voltage applied to the CTO pin sets the NTC high
voltage (normally the cold temperature threshold) for the
For VVCC = 5V, the 40°C NTC network current INTC_HOT
=
NTC input. The default NTC high threshold (VTNTCC×VVCC
)
VVCC/(R3 + RHOT) = 0.246mA. Power dissipation in the
can be selected by connecting the CTO pin to ground. If
it is desired to change this threshold, the voltage on the
thermistor at this temperature, PHOT = RHOT × (INTC_HOT)2 =
0.38mW, for self heating of approximately 0.13°C. The
actual high temperature threshold will thus be lower by
CTO pin can be set between 0.5×VVCC and 0.9×VVCC
.
0.13°C. This self-heating error is usually acceptable. If
it is not, then a thermistor with a greater RHOT must be
chosen.
This feature is especially useful if a single PCB design
is needed to satisfy similar applications with different
requirements. The temperature range for normal charging
can be adjusted by adjusting resistor values on a divider
network without changing the NTC thermistor, which
is often enclosed in the battery pack. An example of a
typical application is shown in Figure 2.
Step 3: Determine the desired high (cold) threshold.
Compute the NTC network resistor divider voltage, as a
function of VVCC, at the cold temperature threshold.
VCC × RCOLD
NTCCOLD
=
= 0.6591 × VCC
R3 + RCOLD
NTC/CTO Design Example
The following example assumes the NTC network
configurationofFigure2, withafixedresistorR3connected
between NTC and VCC, and a battery NTC thermistor
RT connected between NTC and ground. The battery
temperature range over which charging is permitted is
specified to be 0°C through 40°C. The datasheet for the
selected NTC thermistor indicates that RT = 5.839kΩ at
40°C, at RT = 26.49kΩ at 0°C, with a dissipation constant
Step 4: Configure CTO. If NTCCOLD is sufficiently close
to the default cold threshold (VTNTCC×VVCC), then simply
connect CTO to ground, disabling the CTO function, to
complete the design. But in this example it is not, so the
voltage on CTO must be set to 0.6591×VVCC. The simple
resistive voltage divider network of Figure 2 can be used
to obtain the desired CTO voltage.
DC = 3mW. Designate RHOT = 5.839kΩ and RCOLD
26.49kΩ.
=
© 2007 Semtech Corp.
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SC804
POWER MANAGEMENT
Applications Information (Cont.)
during CC charging whenever the current limit of the
charging adapter is less than the SC804 FCI programmed
current. In this case, the adapter voltage (the SC804
input voltage) will be pulled down to the battery voltage
(the SC804 output voltage) plus the dropout voltage.
VCTO = NTCCOLD
VCC × RCT2
= 0.6591 × VCC =
RCT1 + RCT2
Dropout voltage is the larger of two values: (1) the I-R
component, which is the output current multiplied by the
minimum VCC-to-VOUT path resistance (which is highly
temperature dependent), and (2) a regulated minimum
difference voltage, which is output voltage dependent
but is independent of the output current. The regulated
minimum dropout voltage results from the collapse of
internal voltage references as VOUT pulls VCC down to
near, or below, VCV, creating a reduced output regulation
voltage approximately 200mV below VCC. Thus VCC
cannot be pulled down below VOUT + 200mV. The dropout
voltage will be larger than 200mV whenever the minimum
path resistance multiplied by the output current exceeds
200mV, but it cannot be smaller than 200mV.
or
RCT1
RCT2
1 0.6591
=
= 0.5172
0.6591
The choice of RCT1 and RCT2 is somewhat arbitrary. The
simplest approach is to pick one and compute the other.
A good choice here is RCT1 = 115kΩ, and RCT2 = 221kΩ, as
these standard 1% tolerance values produce the closest
match to the desired voltage divider ratio. With these
resistor nominal values,
VCC × RCT2
VCTO
=
= 0.6577 × VCC
R
CT1 + RCT2
This greatest-of-two-limit dropout voltage behavior is
evident in the dropout voltage typical performance plot.
which is, nominally, only 0.2% below the target value of
0.6591×VVCC. The CTO network will present a load of only
15μA to a 5V charging adapter. The nominal impedance
presented to the CTO pin is RCT1 || RCT2 = 75.6kΩ. Any
impedance on the order of 100kΩ (or less) is acceptable.
When operating in Adjust Mode (next section), the
regulated minimum dropout voltage depends on the
programmed VOUT regulation voltage, and dropout also
varies with the actual output voltage during CC charging.
See Figure 4 for an illustration of dropout voltage data.
Remote Kelvin Sensing at the Battery
Adjust Mode
The BSEN pin provides the positive Kelvin sensing voltage
feedback to the CV amplifier and should be connected as
close to the battery + terminal as possible. Likewise, the
RGND pin should be connected directly to the negative
terminal of the battery. This allows the designer great
flexibility in PCB layout and achieves greater accuracy
by sensing the battery voltage directly at the battery
terminals. When laying out the PCB, the designer should
route the BSEN and RGND trace directly to the battery
connection terminals, rather than just to the VOUT and
GND pins on the device.
The SC804 can be configured for an output voltage
other than VCV using Adjust (ADJ) Mode. In Adjust Mode
the output voltage is determined by an external resistor
divider from VOUT to BSEN. When BSEN is connected in
this fashion, VVOUT (during Constant Voltage (CV) charging)
will be controlled such that the voltage at the BSEN pin
(VBSEN) is the reference voltage VBSEN-ADJ
.
The output voltage can be set to any voltage desired by
an appropriate choice of divider network resistors, within
the following limits. When the SC804 is programmed for
adjust mode, VVOUT is required to be 150mV less than VVCC
,
and VVOUT is required to be 400mV greater than VBSEN
.
Dropout Voltage
VVOUT within 150mV of VBSEN guarantees normal mode
operation. This implies that, for BSEN used as a Kelvin
sense of battery voltage, the product of the fast charge
Dropout voltage is the smallest achievable difference
voltage between VCC and VOUT under a particular
operating condition. Dropout voltage is encountered
© 2007 Semtech Corp.
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SC804
POWER MANAGEMENT
Applications Information (Cont.)
Charger VIN
14
13
3
11
10
12
2
VCC
CPB
CHRGB
RTIM
CTO
OV_FLT
OVP
Red
Green
R3
IPRGM
NTC
C1
2.2 μF
7
RCT1
RCT2
4
1
ITERM
FLTB
GND
BSEN
VOUT
VOUT
AFC
RT
NTC
8
16
15
9
R5
R6
6
R1
R2
5
RGND
SC804
C2
R4
2.2μF
ERROR
Figure 2 - Application Circuit with AFC Disabled, and with NTC and CTO Resistor Networks
Charger VIN
14
13
3
11
10
12
2
VCC
CPB
CHRGB
RTIM
CTO
OV_FLT
OVP
Red
Green
R3
IPRGM
NTC
C1
2.2 μF
7
4
1
ITERM
FLTB
GND
BSEN
VOUT
VOUT
AFC
RT
NTC
R11
8
16
15
9
R5
R6
6
R1
R2
5
RGND
C3
C2
2.2μF
SC804
R4
R12
ERROR
Figure 3a - Application Circuit for Adjust Mode
Charger VIN
14
13
3
11
10
12
2
VCC
CPB
CHRGB
RTIM
CTO
OV_FLT
OVP
Red
Green
R3
IPRGM
NTC
C1
2.2 μF
7
4
1
ITERM
FLTB
GND
BSEN
VOUT
VOUT
AFC
RT
NTC
R11
8
16
15
9
R5
R6
6
R1
R2
R4
R12
5
RGND
C3
C2
2.2μF
SC804
ERROR
Figure 3b - Application Circuit for Adjust Mode, with Adapter-only Voltage Sensing
© 2007 Semtech Corp.
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SC804
POWER MANAGEMENT
Applications Information (Cont.)
current and the charge path resistance from VOUT to the
Kelvin sense point should not exceed 150mV to ensure
normal mode operation.
0.8
0.6
0.4
0.2
The SC804 Adjust Mode schematic is shown in Figures 3A
and 3B. Referring to these schematics, the equation for
setting the output voltage is:
R11
R12
VOUT = VBSEN-ADJ_Typ
×
1 +
( )
The capacitor C3 across R8 in the feedback network
introduces zero-pole frequency compensation for stability.
Place the zero according to the following equation to
ensure stability:
3.2
3.4
3.6
3.8
Output voltage, V
4
4.2
4.4
Figure 4 - Adjust Mode Minimum Dropout Voltage
The actual dropout voltage is the greater of the Minimum Dropout
Voltage at various programmed VCV and instantaneous VOUT
voltages (shown here, with several programmed VCV voltages
indicated in the figure by ‘o’), and the IR drop due to the product
of IOUT and RDS-ON (not shown here). Adjust mode operation is
ensured for any IOUT current at programmed VCV voltages up to
approximately 4.25V.
1
R11 × C3 =
2ꢀ × 100kHz
NOTE: WhenusingAdjustModetoprogramaCVregulation
voltage greater than VCV, care must be taken when CC
charging with a charging adapter operating in current
limit. Adapter current-limited operation occurs when
the adapter current limit is less than the programmed
SC804 fast charge current, such that the adapter voltage
is pulled down to VVOUT plus the SC804 dropout voltage. A
low adapter current limit multiplied by the low minimum
path resistance of the main pass transistor and current
sense resistor (as low as 290mΩ total at extremely low
temperature) can result in a voltage drop from VCC to
VOUT of less than 150mV if the Adjust Mode CV regulation
operation. When the device is in charge mode the output
is current-limited to either the pre-charge current limit
value or the fast charge current limit value depending on
the voltage at the output. Max die temperature protection
is also included. This feature allows the SC804 to operate
with maximum power dissipation by disabling the output
current when the die temperature reaches the maximum
operating temperature. The result is that the SC804 will
operate as a pulse charger in extreme power dissipation
applications, delivering the maximum allowable output
current while regulating the internal die temperature to
a safe level.
voltage is programmed above VCV + 50mV. If VVCC - VVOUT
<
150mV, Adjust Mode may not operate correctly. Adjust
Mode will operate correctly whenever the programmed
VOUT CV voltage is less than VCV + 50mV, regardless of the
adapter current limit, because the regulated minimum
dropout voltage is always greater than 150mV in this
case. It will also operate correctly with an adapter current
limit greater than 550 mA, regardless of the programmed
output voltage, because the I-R dropout voltage will
exceed 150mV at even the lowest specified operating
temperature. Normal mode (that is, not Adjust Mode) has
a regulated minimum dropout voltage of approximately
200mV, which is constant for any VVOUT, and so operates
correctly for any adapter current limit.
Indicator Flags
Therearefourindicatoroutputs/LEDdriversontheSC804:
CPB (Charger Present), CHRGB (Charge Active), OVPB
(Over Voltage Fault), and FLTB (Fault). These outputs are
all active-low, open drain NMOS drivers capable of sinking
up to 10mA. The following table defines each indicator’s
output state.
The CPB output can be used as a VCC-present indicator.
Regardless of the state of NTC, the CPB output reflects
the VCC voltage. When VVCC is between the UVLO and OVP
thresholds the CPB output is low. If VVCC is outside these
limits this output is high impedance.
Over current and Max Temperature Protection
Over current protection is inherent in all modes of
© 2007 Semtech Corp.
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SC804
POWER MANAGEMENT
Applications Information (Cont.)
The OVPB signal is an active-low output that signals when
the input voltage exceeds the OVP threshold. When the
voltage on VCC is less than the OVP threshold voltage this
output is high impedance. The FLTB output is activated
when the SC804 experiences a fault condition. This out-
put can be used to notify the system controller of a fault
condition when connected to an interrupt input, or it can
be used like CPB and CHRGB to drive an indicator LED.
The five fault modes signaled by FLTB are: input over-volt-
age, input under-voltage, NTC temperature out of range,
max die temperature (OT), and pre-charge time-out. When
any of these conditions occurs the FLTB output goes low;
otherwise it remains high impedance.
FLAG
ON
OFF
CPB
UVLO < VCC < OVP Input out of range
CHRGB
OVPB
IOUT > ITERM
VCC > OVP
IOUT < ITERM
VCC < OVP
VCC > OVP
VCC UVLO
NTC Temp Fault
Pre-Charge Time-out
(OT (Tj > 150°C)
Normal Operation
or NTC Disable
FLTB
The CHRGB output indicates the charging status. When
the output current is greater than ITERM, CHRGB is low.
CHRGB is high impedance when IOUT is less than ITERM.
The CHRGB output is latched during the charge cycle when
the output current is less than ITERM. This latch is reset
when the battery enters a recharge cycle, or if NTC or VCC
are toggled.
Capacitor Selection
Low cost, low ESR ceramic capacitors such as the X5R
and X7R dielectric material types are recommended for
use with the SC804. The output capacitance range is 1ꢀF
to 4.7ꢀF. The input capacitor is typically between 0.1ꢀF to
1ꢀF, but Charge Mode Timing Diagram larger values will
not degrade performance.
Charge Mode Timing Diagram
UVLO
VCC
2.8V
VOUT
Re- Charge
Threshold
Fast Charge
Termination
Current
Soft Start
Pre- Charge
IOUT
CV Mode
CC Mode
CPB
CHRGB
On
Off
On
On
Off
On
On
On
Hold
TIMER
FLTB
Off
Off
On
Off
NTC
Fault
Figure 5 - Charge Mode Timing
© 2007 Semtech Corp.
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SC804
POWER MANAGEMENT
State Diagram
Over-Voltage, Under-Voltage or
Shutdown Mod:e
Over-Temperature will force the
SC804 into Shutdown Mode
from any state.
VOUT &IOUT off,
OVP > VCC> UVLO
En =Hi
CHRGB High Z,
CPB Low.
Yes
CC = Constant Current
CV = Constant Voltage
Soft Start Vout
CHRGB Low
Timer
Enabled?
Yes
Start Timer
Start Pre- Charge
Yes
Soft Start CC Mode
V
OUT > VTPreQ
OUT =IPREQ
IOUT =IFAST
I
Time>TMAX/4
Yes
V
OUT =VCV
Pre- Charge
Timeout Fault
FLTB goes low.
Cleared by
Yes
Start CV Mode
VBAT> VTPreQ
or Re- cycle VCC
IOUT <ITERM
low temp> NTC Temp> high temp
Yes
CHRGB High Z
NTC out of Range Fault
FLTB goes active low
Timer is frozen
Charge resumes when NTC
Temperature is valid
Timer
Enabled?
Yes
Yes
Monitor Mode
Time>TMAX
VOUT off
Yes
Float Charge Mode
OUT
V
CV
ReQ
<V - V
VOUT =VCV
© 2007 Semtech Corp.
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SC804
POWER MANAGEMENT
Typical Charge Cycle
Typical Charge Cycle
Evaluation Board configured for internal timer, 1.5V on IPRGM = 810mA, 1.5V on ITERM = 300mA, VCC = 5.0V, Li-Ion battery capacity =
1000mAh. A 70mA battery load was applied after initial charge timeout, and removed during the recharge cycle prior to termination.
(a) Constant Current (CC) Charging (Fast Charge); (b) Constant Voltage (CV) Charging; (c) Termination; (d) Float Charging; (e) Timer Expiration;
(f) Slow Battery Discharge; (g) Recharge; (h) Termination.
4.5
Battery Voltage
(f)
(b
(d)
4
3.5
3
(h)
(a)
(c)
CHRGB Voltage
(g)
2.5
2
(e)
ITERM Voltage
1.5
1
CHRGB Voltage
0.5
0
ITERM Voltage
IPRGM Voltage
2.5
0
0.5
1
1.5
2
3
3.5
4
4.5
Time, hours
© 2007 Semtech Corp.
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SC804
POWER MANAGEMENT
Typical Characteristics
VOUT Vcv Line Regulation vs. Load, T = +25°C
VOUT Vcv Line Regulation vs. Load, T = +25°C
4.220
4.215
4.210
4.205
4.200
4.195
4.220
Iout = 500mA
Iout = 750mA
VCC = 5.0V
VCC = 5.5V
4.215
4.210
VCC = 6.0V
Iout = 1000mA
4.205
VCC = 6.5V
Iout = 1500mA
4.200
4.195
5.00
5.20
5.40
5.60
5.80
6.00
6.20
6.40
500
750
1000
1250
1500
VIN (V)
IOUT (mA)
VOUT Vcv Regulation vs. Temperature,
VCC = 5.0V, Iout = 800mA
IOUT Line Regulation vs. Temperature,
RPRGM = 1.87kΩ
808
806
804
802
800
798
796
794
792
4.220
4.215
4.210
4.205
4.200
4.195
T = +85°C
T = +25°C
T = -40°C
-50
-25
0
25
50
75
100
4.25
4.50
4.75
5.00
5.25
5.50
5.75
6.00
6.25
6.50
6.75
VCC (V)
Ambient Temperature, °C
IOUT vs. IPRGM Resistance, T = +25°C
Precharge & Termination Current vs. ITERM Resistance
1600
1400
1200
1000
800
400
350
300
250
200
150
100
50
600
400
0
0.3
0.5
0.7
0.9
1.1
0
0.5
1
1.5
2
2.5
Riprgm1/kΩ
Riprgm1/kΩ
© 2007 Semtech Corp.
17
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SC804
POWER MANAGEMENT
Typical Characteristics (Cont.)
Dropout Voltage vs. IOUT
Rds-on vs. IOUT
0.620
0.570
0.520
0.470
0.420
0.370
0.320
0.270
0.900
TJ = +125°C
0.800
TJ = +125°C
0.700
TJ = +85°C
0.600
TJ = +85°C
0.500
0.400
0.300
TJ = +25°C
TJ = +25°C
TJ = -40°C
0.200
TJ = - 40°C
0.100
400
600
800
1000
1200
1400
1600
400
600
800
1000
1200
1400
1600
IOUT (mA)
IOUT (mA)
AFC Operation, RPRGM = 1.78kΩ
1200
1000
800
600
400
200
0
AFC Pin Tied to VCC
Actual AFC Response
Ideal AFC Response
0
0.5
1
1.5
2
VAFC, V
© 2007 Semtech Corp.
18
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SC804
POWER MANAGEMENT
Evaluation Board Schematic
CHARGER+
CHARGER-
RTIM
C1
1
2
2.2u
R9
R10
1
2
2
1
<NM>
<NM>
JP6
JP1
D1
1
1
2
R1
VOUT
2
1
2
2
1
D2
D3
D4
390
R15
1
2
1
R11
0
C2
2.2u
C3
<NM>
1
2
GND
CTO
1
1
37.4k
1
2
3
4
12
BSEN
CTO
RTIM
CPB
3
2
1
R2
JP2
JP3
JP5
11
10
9
1
1
2
2
1
1
2
U1
390
R3
SC804
1
2
IPRGM
ITERM
CHRGB
AFC
390
R13
JP7
IPRGM
ITERM
2
1
2
1
1
100k
R12
<NM>
R6
1.87k
R5
499
R4
JP4
1
2
1
2
R14
390
2
1
1
2
1
1
RGND
0
R8
R7
1
2
GND
GND
1
1
<NM>
R16
10k
3
1
NTC
POT_3296W-105
Evaluation Board Gerber Plots
© 2007 Semtech Corp.
19
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SC804
POWER MANAGEMENT
Outline Drawing - MLPQ-16
DIMENSIONS
INCHES MILLIMETERS
DIM
MIN NOM MAX MIN NOM MAX
A
D
-
-
-
-
A
.031
A1 .000
.040 0.80
.002 0.00
1.00
0.05
-
B
E
-
(.008)
-
-
(0.20)
A2
b
D
.010 .012 .014 0.25 0.30 0.35
.153 .157 .161 3.90 4.00 4.10
PIN 1
INDICATOR
(LASER MARK)
D1 .079 .085 .089 2.00 2.15 2.25
.153 .157 .161 3.90 4.00 4.10
E1 .079 .085 .089 2.00 2.15 2.25
E
e
.026 BSC
0.65 BSC
L
N
.012 .016 .020 0.30 0.40 0.50
16
16
aaa
bbb
.003
.004
0.08
0.10
A2
A
SEATING
PLANE
aaa C
A1
C
D1
e/2
LxN
E/2
E1
2
1
N
e
bxN
bbb
C
A B
D/2
NOTES:
1. CONTROLLING DIMENSIONS ARE IN MILLIMETERS (ANGLES IN DEGREES).
2. COPLANARITY APPLIES TO THE EXPOSED PAD AS WELL AS THE TERMINALS.
Marking Information
804
yyww
xxxxx
xxxx
yyww = Date Code
Example (0552)
xxxxx xxxx = Semtech Lot Number
Example: (E9010 01-1)
© 2007 Semtech Corp.
20
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SC804
POWER MANAGEMENT
Land Pattern - MLPQ-16
K
DIMENSIONS
INCHES MILLIMETERS
DIM
(.156)
.122
.091
.091
.026
.016
.033
.189
(3.95)
3.10
2.30
2.30
0.65
0.40
0.85
4.80
C
G
H
K
P
X
Y
Z
2x Z
H
2x G
Y
2x (C)
X
P
NOTES:
1.
THIS LAND PATTERN IS FOR REFERENCE PURPOSES ONLY.
CONSULT YOUR MANUFACTURING GROUP TO ENSURE YOUR
COMPANY'S MANUFACTURING GUIDELINES ARE MET.
Contact Information
Semtech Corporation
Power Management Products Division
200 Flynn Road, Camarillo, CA 93012
Phone: (805) 498-2111 FAX (805)498-3804
© 2007 Semtech Corp.
21
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