DS04-27709-3E
FUJITSU SEMICONDUCTOR
DATA SHEET
ASSP F or Power Supply Applications (Secondary battery)
DC/DC Converter IC
for Charging Li-ion battery
MB3887
■DESCRIPTION
The MB3887 is a DC/DC converter IC suitable for down-conversion, using pulse-width (PWM) charging and
enabling output voltage to be set to any desired level from one cell to four cells.
These ICs can dynamically control the secondary battery’s charge current by detecting a voltage drop in an AC
adapter in order to keep its power constant (dynamically-controlled charging) .
The charging method enables quick charging, for example, with the AC adapter during operation of a notebook PC.
The MB3887 provides a broad power supply voltage range and low standby current as well as high efficiency,
making it ideal for use as a built-in charging device in products such as notebook PC.
This product is covered by US Patent Number 6,147,477.
■FEATURES
• Detecting a voltage drop in the AC adapter and dynamically controlling the charge current
(Dynamically-controlled charging)
(Continued)
■PACKAGE
24-pin plastic SSOP
(FPT-24P-M03)
MB3887
2
(Continued)
• Output voltage setting using external resistor : 1 cell to 4 cells
• High efficiency : 96% (VIN = 19 V, Vo = 16.8 V)
• Wide range of operating supply voltages : 8 V to 25 V
• Output voltage setting accuracy : 4.2 V ± 0.74% (T a = −10 °C to +85 °C , per cell)
• Charging current accuracy : ±5%
• Built-in frequency setting capacitor enables frequency setting using external resistor only
• Oscillation frequency range : 100 kHz to 500 kHz
• Built-in current detection amplifier with wide in-phase input voltage range : 0 V to VCC
• In standby mode, leave output voltage setting resistor open to prevent inefficient current loss
• Built-in standby current function : 0 µA (standard)
• Built-in soft-start function independent of loads
• Built-in totem-pole output stage supporting P-channel MOS FET devices
MB3887
3
■PIN ASSIGNMENT
(TOP VIEW)
(FPT-24P-M03)
1
2
3
4
5
6
7
8
9
10
11
12
−INC2 :
OUTC2 :
+INE2 :
−INE2 :
FB2 :
VREF :
FB1 :
−INE1 :
+INE1 :
OUTC1 :
OUTD :
−INC1 :
24
23
22
21
20
19
18
17
16
15
14
13
: +INC2
: GND
: CS
: VCC (O)
: OUT
: VH
: VCC
: RT
: −INE3
: FB3
: CTL
: +INC1
MB3887
4
■PIN DESCRIPTION
Pin No. Symbol I/O Descriptions
1−INC2 I Current detection amplifier (Current Amp2) input terminal.
2 OUTC2 O Current detection amplifier (Current Amp2) output terminal.
3+INE2 I Error amplifier (Error Amp2) non-inverted input terminal.
4−INE2 I Error amplifier (Error Amp2) inverted input terminal.
5 FB2 O Error amplifier (Error Amp2) output terminal.
6 VREF O Reference voltage output terminal.
7 FB1 O Error amplifier (Error Amp1) output terminal.
8−INE1 I Error amplifier (Error Amp1) inverted input terminal
9+INE1 I Error amplifier (Error Amp1) non-inverted input terminal.
10 OUTC1 O Current detection amplifier (Current Amp1) output terminal.
11 OUTD O With IC in standby mode, this terminal is set to “Hi-Z” to prevent loss
of current through output voltage setting resistance.
Set CTL terminal to “H” level to output “L” level.
12 −INC1 I Current detection amplifier (Current Amp1) input terminal.
13 +INC1 I Current detection amplifier (Current Amp1) input terminal.
14 CTL I Power supply control terminal.
Setting the CTL terminal at “L” level places the IC in the standby
mode.
15 FB3 O Error amplifier (Error Amp3) output terminal.
16 −INE3 I Error amplifier (Error Amp3) inverted input terminal.
17 RT Triangular-wave oscillation frequency setting resistor connection
terminal.
18 VCC Power supply terminal for reference power supply and control circuit.
19 VH O Power supply terminal for FET drive circuit (VH = VCC − 6 V) .
20 OUT O External FET gate drive terminal.
21 VCC (O) Output circuit power supply terminal.
22 CS Soft-start capacitor connection terminal.
23 GND Ground terminal.
24 +INC2 I Current detection amplifier (Current Amp2) input terminal.
MB3887
5
■BLOCK DIAGRAM
+
−−
+
8
10
13
12
9
+
−−
+
4
2
24
1
3
× 20
× 20
+
+
+
−
5
20
21
19
−
+
+
+
−
11
16
22
17 6 23
14
18
<Current Amp1> <Error Amp1>
7
VREF
<Current Amp2> <Error Amp2>
VREF
<Error Amp3>
VREF
VREF
VREF
5.0 V
4.2 V
10
µA
15 <SOFT>
2.5 V
1.5 V
<OUT>
<UVLO>
<OSC>
Bias
Voltage
<VH>
<REF> <CTL>
<PWM Comp.>
Drive
VCC
(VCC − 6 V)
(VCC UVLO)
VCC
VCC
VCC
CTL
215 kΩ
35 kΩ
0.91 V
(0.77 V)
VREF
UVLO
4.2 V
bias
−INC2
OUTD
FB2
OUTC2
VREF
−INE2
+INE2
+INE1
FB1
OUTC1
−INE1
−INC1
+INC2
GND
CS
VCC (O)
OUT
VH
RT
−INE3
FB3
+INC1
45 pF
MB3887
6
■ABSOLUTE MAXIMUM RATINGS
* : The package is mounted on the dual-sided epoxy board (10 cm × 10 cm) .
WARNING: Semiconductor devices can be permanently damaged by application of stress (voltage, current,
temperature, etc.) in excess of absolute maximum ratings. Do not exceed these ratings.
Parameter Symbol Conditions Rating Unit
Min Max
Power supply voltage VCC VCC, VCC (O) terminal 28 V
Output current IOUT 60 mA
Peak output current IOUT Duty ≤ 5 %
(t = 1 / fOSC × Duty) 700 mA
Power dissipation PDTa ≤ +25 °C740* mW
Storage temperature TSTG −55 +125 °C
MB3887
7
■RECOMMENDED OPERATING CONDITIONS
WARNING: The recommended operating conditions are required in order to ensure the normal operation of the
semiconductor device. All of the device’s electrical characteristics are warranted when the device is
operated within these ranges.
Always use semiconductor devices within their recommended operating condition ranges. Operation
outside these ranges may adversely affect reliability and could result in device failure.
No warranty is made with respect to uses, operating conditions, or combinations not represented on
the data sheet. Users considering application outside the listed conditions are advised to contact their
FUJITSU representatives beforehand.
Parameter Symbol Conditions Value Unit
Min Typ Max
Power supply voltage VCC VCC, VCC (O) terminal 8 25 V
Reference voltage output
current IREF −10mA
VH ter m inal output current IVH 030 mA
Input voltage VINE −INE1 to −INE3, +INE1,
+INE2 terminal 0VCC − 1.8 V
VINC +INC1, +INC2, −INC1,
−INC2 terminal 0VCC V
OUTD terminal
output voltage VOUTD 017 V
OUTD terminal
output current IOUTD 02mA
CTL terminal input voltage VCTL 025 V
Output current IOUT −45 +45 mA
Peak output current IOUT Duty ≤ 5 %
(t = 1 / fosc × Duty) −600 +600 mA
Oscillation frequency fOSC 100 290 500 kHz
Timing resistor RT27 47 130 kΩ
Soft-start capacitor CS0.022 1.0 µF
VH ter m inal capacitor CVH 0.1 1.0 µF
Reference voltage output
capacitor CREF 0.1 1.0 µF
Operating ambient
temperature Ta −30 +25 +85 °C
MB3887
8
■ELECTRICAL CHARACTERISTICS (Ta = +25 °C, VCC = 19 V, VCC (O) = 19 V, VREF = 0 mA)
* : Standard design value.
(Continued)
Parameter Sym-
bol Pin
No. Conditions Value Unit
Min Typ Max
1.
Reference
voltage block
[REF]
Output voltage VREF1 6Ta = +25 °C 4.967 5.000 5.041 V
VREF2 6Ta = −10 °C to +85 °C 4.95 5.00 5.05 V
Input stability Line 6 VCC = 8 V to 25 V 310mV
Load stability Load 6 VREF = 0 mA to −1 mA 110mV
Short-circuit output
current Ios 6 VREF = 1 V −50 −25 −12 mA
2.
Under voltage
lockout protec-
tion circuit
block
[UVLO]
Threshold voltage VTLH 18 VCC = VCC (O) ,
VCC = 6.2 6.4 6.6 V
VTHL 18 VCC = VCC (O) ,
VCC = 5.2 5.4 5.6 V
Hysteresis width VH18 VCC = VCC (O) 1.0* V
Threshold voltage VTLH 6VREF = 2.6 2.8 3.0 V
VTHL 6VREF = 2.4 2.6 2.8 V
Hysteresis width VH60.2 V
3.
Soft-start block
[SOFT] Charge current ICS 22 −14 −10 −6µA
4.
Triangular
waveform os-
cillator circuit
block
[OSC]
Oscillation
frequency fOSC 20 RT = 47 kΩ260 290 320 kHz
Frequency
temperature
stability ∆f/fdt 20 Ta = −30 °C to +85 °C 1* %
5-1.
Error amplifier
block
[Error Amp1,
Error Amp2]
Input offset voltage VIO 3, 4,
8, 9 FB1 = FB2 = 2 V 15mV
Input bias current IB3, 4,
8, 9
−100 −30 nA
In-phase input
voltage range VCM 3, 4,
8, 9
0VCC − 1.8 V
Voltage gain AV5, 7 DC 100* dB
Frequency
bandwidth BW 5, 7 AV = 0 dB 2* MHz
Output voltage VFBH 5, 7 4.7 4.9 V
VFBL 5, 7 20 200 mV
Output source
current ISOURCE 5, 7 FB1 = FB2 = 2 V −2−1mA
Output sink current ISINK 5, 7 FB1 = FB2 = 2 V 150 300 µA
MB3887
9
(Ta = +25 °C, VCC = 19 V, VCC (O) = 19 V, VREF = 0 mA)
* : Standard design value
(Continued)
Parameter Sym-
bol Pin
No. Conditions Value Unit
Min Typ Max
5-2.
Error amplifier
block
[Error Amp3]
Threshold voltage VTH1 16 FB3 = 2 V, Ta = +25 °C 4.183 4.200 4.225 V
VTH2 16 FB3 = 2 V,
Ta = −10 °C to +85 °C 4.169 4.200 4.231 V
Input current IINE3 16 −INE3 = 0 V −100 −30 nA
Voltage gain AV15 DC 100* dB
Frequency
bandwidth BW 15 AV = 0 dB 2* MHz
Output voltage VFBH 15 4.7 4.9 V
VFBL 15 20 200 mV
Output source
current ISOURCE 15 FB3 = 2 V −2−1mA
Output sink current ISINK 15 FB3 = 2 V 150 300 µA
OUTD terminal
output leak current ILEAK 11 OUTD = 17 V 01µA
OUTD terminal
output ON resistor RON 11 OUTD = 1 mA 35 50 Ω
6.
Current detec-
tion amplifier
block
[Current
Amp1, Current
Amp2]
Input offset voltage VIO
1,
12,
13,
24
+INC1 = +INC2 = −INC1
= −INC2 = 3 V to VCC −3+3mV
Input current
I+INCH 13,
24
+INC1 = +INC2 =
3 V to VCC,
∆VIN = −100 mV 20 30 µA
I−INCH 1, 12 +INC1 = +INC2 =
3 V to VCC,
∆Vin = −100 mV 0.1 0.2 µA
I+INCL 13,
24 +INC1 = +INC2 = 0 V,
∆Vin = −100 mV −180 −120 µA
I−INCL 1, 12 +INC1 = +INC2 = 0 V,
∆Vin = −100 mV −195 −130 µA
MB3887
10
(Ta = +25 °C, VCC = 19 V, VCC (O) = 19 V, VREF = 0 mA)
* : Standard design value
(Continued)
Parameter Sym-
bol Pin
No. Conditions Value Unit
Min Typ Max
6.
Current
detection
amplifier block
[Current Amp1,
Current Amp2]
Current detection
voltage
VOUTC1 2, 10 +INC1 = +INC2 =
3 V to VCC,
∆Vin = −100 mV 1.9 2.0 2.1 V
VOUTC2 2, 10 +INC1 = +INC2 =
3 V to VCC,
∆Vin = −20 mV 0.34 0.40 0.46 V
VOUTC3 2, 10 +INC1 = +INC2 =
0 V to 3 V,
∆Vin = −100 mV 1.8 2.0 2.2 V
VOUTC4 2, 10 +INC1 = +INC2 =
0 V to 3 V,
∆Vin = −20 mV 0.2 0.4 0.6 V
In-phase input
voltage range VCM
1,
12,
13,
24
0VCC V
Voltage gain AV2, 10 +INC1 = +INC2 =
3 V to VCC,
∆Vin = −100 mV 19 20 21 V/V
Frequency
bandwidth BW 2, 10 AV = 0 dB 2* MHz
Output voltage VOUTCH 2, 10 4.7 4.9 V
VOUTCL 2, 10 20 200 mV
Output source
current ISOURCE 2, 10 OUTC1 = OUTC2 = 2 V −2−1mA
Output sink cur-
rent ISINK 2, 10 OUTC1 = OUTC2 = 2 V 150 300 µA
7.
PWM
comparator
block
[PWM Comp.]
Threshold voltage
VTL 5, 7,
15 Duty cycle = 0 %1.4 1.5 V
VTH 5, 7,
15 Duty cycle = 100 %2.5 2.6 V
MB3887
11
(Continued)
(Ta = +25 °C, VCC = 19 V, VCC (O) = 19 V, VREF = 0 mA)
* : Standard design value
Parameter Sym-
bol Pin
No. Conditions Value Unit
Min Typ Max
8.
Output block
[OUT]
Output source
current ISOURCE 20 OUT = 13 V, Duty ≤ 5 %
(t = 1 / fOSC × Duty) −400* mA
Output sink
current ISINK 20 OUT = 19 V, Duty ≤ 5 %
(t = 1 / fOSC × Duty) 400* mA
Output ON
resistor ROH 20 OUT = −45 mA 6.5 9.8 Ω
ROL 20 OUT = 45 mA 5.0 7.5 Ω
Rise time tr1 20 OUT = 3300 pF
(Si4435 × 1) 50* ns
Fall time tf1 20 OUT = 3300 pF
(Si4435 × 1) 50* ns
9.
Control block
[CTL]
CTL input voltage VON 14 IC Active mode 2 25 V
VOFF 14 IC Standby mode 0 0.8 V
Input current ICTLH 14 CTL = 5 V 100 150 µA
ICTLL 14 CTL = 0 V 01µA
10.
Bias voltage
block
[VH]
Output voltage VH19 VCC = VCC (O)
= 8 V to 25 V,
VH = 0 to 30 mA VCC − 6.5 VCC − 6.0 VCC − 5.5 V
11.
General
Standby current ICCS 18 VCC = VCC (O) ,
CTL = 0 V 010µA
Power supply cur-
rent ICC 18 VCC = VCC (O) ,
CTL = 5 V 812mA
MB3887
12
■TYPICAL CHARACTERISTICS
(Continued)
6
5
4
3
2
1
00 5 10 15 20 25
Ta = +25 °C
CTL = 5 V
6
5
4
3
2
1
00 5 10 15 20 25
Ta = +25 °C
CTL = 5 V
VREF = 0 mA
6
5
4
3
2
1
00 5 10 15 20 25 30
Ta = +25 °C
VCC = 19 V
CTL = 5 V
5.08
5.06
5.04
5.02
5.00
4.98
4.96
4.94
4.92−40 −20 0 20 40 60 80 100
VCC = 19 V
CTL = 5 V
1000
900
800
700
600
500
400
300
200
100
0
10
9
8
7
6
5
4
3
2
1
0
0 5 10 15 20 25
VREF
ICTL
Ta = +25 °C
VCC = 19 V
Power supply current ICC (mA)
Power supply current vs. Power supply voltage
Power supply voltage VCC (V)
Reference voltage VREF (V)
Power supply voltage VCC (V)
Reference voltage vs. Power supply voltage
Reference voltage VREF (V)
IREF load current IREF (mA)
Reference voltage vs. IREF load current Reference voltage vs. Ambient temperature
Reference voltage VREF (V)
Ambient temperature Ta ( °C)
CTL terminal current, Reference voltage
vs. CTL terminal voltage
CTL terminal current ICTL (µA)
CTL terminal voltage VCTL (V)
Reference voltage VREF (V)
MB3887
13
(Continued)
1 M
100 k
10 k10 100 1000
Ta = +25 °C
VCC = 19 V
CTL = 5 V
340
330
320
310
300
290
280
270
260 0 5 10 15 20 25
Ta = +25 °C
CTL = 5 V
RT = 47 kΩ
320
315
310
305
300
295
290
285
280
275
270
265
260−40 −20 0 20 40 60 80 100
VCC = 19 V
CTL = 5 V
RT = 47 kΩ
4.25
2.24
4.23
2.22
4.21
4.20
4.19
4.18
4.17
4.16
4.15−40 −20 0 20 40 60 80 100
VCC = 19 V
CTL = 5 V
Triangular wave oscillation frequency
vs. Timing resistor
Triangular wave oscillation
frequency fOSC (Hz)
Timing resistor RT (kΩ)
Triangular wave oscillation frequency
vs. Power supply voltage
Triangular wave oscillation
frequency fOSC (kHz)
Power supply voltage VCC (V)
Triangular wave oscillation frequency
vs. Ambient temperature
Triangular wave oscillation
frequency fOSC (kHz)
Ambient temperature Ta ( °C)
Error amplifier threshold voltage
vs. Ambient temperature
Error amplifier threshold
voltage VTH (V)
Ambient temperature Ta ( °C)
MB3887
14
(Continued)
−
+
7
8
9
+
OUT
IN
(5)
(4)
(3)
240 kΩ
2.4 kΩ
10 kΩ
10 kΩ10 kΩ
10 kΩ
Error Amp1
(Error Amp2)
4.2 V VCC = 19 V
1 µF
Ta = +25 °C
AV
φ
40
20
0
−20
−40
180
90
0
−90
−180
1 k 10 k 100 k 1 M 10 M
−
+
+
15
16
22
+
OUT
IN
240 kΩ
2.4 kΩ
10 kΩ
10 kΩ10 kΩ
10 kΩ
Error Amp3
4.2 V
4.2 V
VCC = 19 V
1 µF
Ta = +25 °C
AV
φ
40
20
0
−20
−40
180
90
0
−90
−180
1 k 10 k 100 k 1 M 10 M
Ta = +25 °C
AV
φ
40
20
0
−20
−40
180
90
0
−90
−180
1 k 10 k 100 k 1 M 10 M
+
−10
13
12
VCC = 19 V
×20
(24)
(1) (2) OUT
12.55 V12.6 V
Current Amp1
(Current Amp2)
Error amplifier gain and phase vs. Frequency
Gain AV (dB)
Frequency f (Hz)
Phase φ (deg)
Current detection amplifier gain and phase vs. Frequency
Gain AV (dB)
Frequency f (Hz)
Phase φ (deg)
Error amplifier gain and phase vs. Frequency
Gain AV (dB)
Frequency f (Hz)
Phase φ (deg)
MB3887
15
(Continued)
800
700
600
500
400
300
200
100
0
740
−40 −20 0 20 40 60 80 100
Power dissipation vs. Ambient temperature
Power dissipation PD (mW)
Ambient temperature Ta ( °C)
MB3887
16
■FUNCTIONAL DESCRIPTION
1. DC/DC Converter Unit
(1) Reference voltage block (Ref)
The reference voltage generator uses the voltage supplied from the VCC ter minal (pin 18) to generate a tem-
perature-compensated, stable voltage (5.0 V Typ) used as the reference supply voltage for the IC’s internal
circuitry.
This terminal can also be used to obtain a load current to a maximum of 1mA from the ref erence voltage VREF
terminal (pin 6) .
(2) Triangular wave oscillator block (OSC)
The triangular wa ve oscillator builds the capacitor for frequency setting into, and generates the triangular wa ve
oscillation waveform by connecting the frequency setting resistor with the RT terminal (pin 17) .
The triangular wave is input to the PWM comparator on the IC.
(3) Err or amplifier block (Error Amp1)
This amplifier detects the output signal from the current detection amplifier (Current amp1) , compares this to
the +INE1 terminal (pin 9) , and outputs a PWM control signal to be used in controlling the charging current.
In addition, an arbitrary loop gain can be set up by connecting a fe edback resistor and capacitor between the
FB1 terminal (pin 7) and -INE1 terminal (pin 8) , providing stable phase compensation to the system.
(4) Error amplifier block (Error Amp2)
This amplifier (Error Amp2) detects voltage drop of the AC adapter and outputs a PWM control signal.
In addition, an arbitrary loop gain can be set by connecting a feedback resistor and capacitor from the FB2
terminal (pin 5) to the −INE2 terminal (pin 4) of the error amplifier, enabling stable phase compensation to the
system.
(5) Error amplifier block (Error Amp3)
This error amplifier (Error Amp3) detects the output vo ltage from the DC/DC conver ter and outputs the PWM
control signal. External output voltage setting resistors can be connected to the error amplifier inver ted input
terminal to set the desired level of output voltage from 1 cell to 4 cells.
In addition, an arbitrary loop gain can be set by connecting a feedback resistor and capacitor from the FB3
ter minal (pin 15) to the −INE3 terminal (pin 16) of the error amplifier, enabling stable phase compensation to
the system.
Connecting a soft-start capacitor to the CS terminal (pin 22) prevents rush currents when the IC is turned on.
Using an error amplifier for soft-start detection makes the soft-start time constant, independent of the output load.
(6) Current detection amplifier block (Current Amp1)
The current detection amplifier (Current Amp1) detects a voltage drop which occurs between both ends of the
output sense resistor (RS) due to the flow of the charge current, using the +INC1 terminal (pin 13) and −INC1
terminal (pin 12) . Then it outputs the signal amplified by 20 times to the error amplifier (Error Amp1) at the ne xt
stage.
MB3887
17
(7) PWM comparator block (PWM Comp.)
The PWM comparator circuit is a voltage-pulse width converter for controlling the output duty of the error
amplifiers (Error Amp1 to Error Amp3) depending on their output voltage.
The PWM comparator circuit compares the triangular wave generated by the tr iangular wave oscillator to the
error amplifier output voltage and turns on the external output transistor during the interval in which the triangular
wave voltage is lower than the error amplifier output voltage.
(8) Output block (OUT)
The output circuit uses a totem-pole configuration capable of driving an external P-channel MOS FET.
The output “L” le v el sets the output amplitude to 6 V (Typ) using the voltage generated b y the bias v oltage b lock
(VH) .
This results in increasing conv ersion efficiency and suppressing the withstand voltage of the connected e xternal
transistor in a wide range of input voltages.
(9) Control block (CTL)
Setting the CTL terminal (pin 14) low places the IC in the standby mode. (The supply current is 10 µA at maximum
in the standby mode.)
CTL function table
(10) Bias voltage block (VH)
The bias voltage circuit outputs VCC −6 V (Typ) as the minimum potential of the output circuit. In the standby
mode, this circuit outputs the potential equal to VCC.
2. Protection Functions
Under voltage lockout protection circuit (UVLO)
The transient state or a momentary decrease in supply voltage or internal reference voltage (VREF) , which
occurs when the power supply (VCC) is turned on, may cause malfunctions in the control IC, resulting in
breakdown or degradation of the system.
To prevent such malfunction, the under voltage lockout protection circuit detects a supply voltage or internal
ref erence voltage drop and fix es the OUT terminal (pin 20) to the “H” le v el. The system restores voltage supply
when the supply v oltage or internal reference v oltage reaches the threshold v oltage of the under voltage loc kout
protection circuit.
Protection circuit (UVLO) operation function table
When UVLO is operating (VCC or VREF voltage is lower than UVLO threshold voltage.)
CTL Power OUTD
L OFF (Standby) Hi-Z
HON (Active) L
OUTD OUT CS
Hi-Z H L
MB3887
18
3. Soft-Start Function
Soft-start block (SOFT)
Connecting a capacitor to the CS ter minal (pin 22) prevents r ush currents when the IC is tur ned on. Using an
error amplifier for soft-start detection makes the soft-star t time constant, being independent of the output load
of the DC/DC converter.
■SETTING THE CHARGING VOLTAGE
The charging voltage (DC/DC output voltage) can be set by connecting exter nal voltage setting resistors (R3,
R4) to the −INE3 ter minal (pin 16) . Be sure to select a resistor value that allows you to ignore the on-resistor
(35 Ω, 1mA) of the internal FET connected to the OUTD terminal (pin 11) . In standby mode, the charging
v oltage is applied to OUTD termial. Therefore , output voltage m ust be adjusted so that voltage applied to OUTD
terminal is 17 V or less.
Battery charging voltage : VO
VO (V) = (R3 + R4) / R4 × 4.2 (V)
■METHOD OF SETTING THE CHARGING CURRENT
The charge current (output limit current) value can be set with the voltage at the +INE1 terminal (pin 9) .
If a current exceeding the set value attempts to flow, the charge voltage drops according to the set current value.
Battery charge current setting voltage : +INE1
+INE1 (V) = 20 × I1 (A) × RS (Ω)
■METHOD OF SETTING THE TRIANGULAR WAVE OSCILLATION FREQUENCY
The triangular wave oscillation frequency can be set by the timing resistor (RT) connected the RT terminal (pin 17) .
Triangular wave oscillation frequency : fOSC
fOSC (kHz) := 13630 / RT (kΩ)
<Error Amp3>
−
+
+
4.2 V
R3
VO
R4
−INE3
OUTD
CS
16
B
11
22
MB3887
19
■METHOD OF SETTING THE SOFT-START TIME
F or preventing rush current upon activation of IC, the IC allo ws soft-start using the capacitor (Cs) connected to
the CS terminal (pin 22) .
When CTL ter minal (pin 14) is placed under “H” level and IC is activated (VCC ≥ UVLO threshold voltage) , Q2
is turned off and the external soft-start capacitor (Cs) connected to the CS terminal is charged at 10 µA.
Error Amp output (FB3 ter minal (pin 15) ) is determined by comparison between the lower voltage of the two
non-re v erse input terminals (4.2 V and CS terminal voltage) and re verse input terminal v oltage (−INE3 terminal
(pin 16) v oltage) . Within the soft-start period (CS terminal v oltage < 4.2 V) , FB3 is determined by comparison
between −INE3 terminal v oltage and CS terminal voltage, and DC/DC con verter output voltage goes up propor-
tionately with the increase of CS terminal voltage caused by charging on the soft-start capacitor.Soft-start time
is found by the following formula :
Soft-start time : ts (time to output 100 %)
tS (s) := 0.42 × CS (µF)
= 4.9 V
= 4.2 V
= 0 V
CS terminal voltage
Comparison with Error Amp block − INE3
voltage.
Soft-start time: ts
15
16
22
−
+
+
UVLO
VREF
10 µA 10 µA
Q2
4.2 V
Error
Amp3
FB3
−INE3
CS
CS
Soft-start circuit
MB3887
20
■AC ADAPTOR VOLTAGE DETECTION
• With an exter nal resistor connected to the +INE2 ter minal (pin 3) , the IC enters the dynamically-controlled
charging mode to reduce the charge current to keep AC adapter power constant when the par tial potential
point A of the AC adapter voltage (VCC) becomes lower than the voltage at the −INE2 terminal.
AC adapter detection voltage setting : Vth
Vth (V) = (R1 + R2) / R2 × −INE2
■OPERATION TIMING DIAGRAM
−
+
VCC R1
R2
+INE2
−INE2
A
<Error Amp2>
4
3
2.5 V
1.5 V
Error Amp2 FB2
Error Amp1 FB1
Error Amp2 FB3
OUT
Constant voltage control Constant current control AC adapter dynamically-
controlled charging
MB3887
21
■PROCESSING WITHOUT USING THE CURRENT AMP
When Current Amp is not used, connect the +INC1 terminal (pin 13) , +INC2 terminal (pin 24) , −INC1 terminal
(pin 12) , and −INC2 ter minal (pin 1) to VREF, and then leave OUTC1 terminal (pin 10) and OUTC2 ter minal
(pin 2) open.
24
1312
1
2
10
6
−INC1 +INC1
+INC2
−INC2
OUTC1
OUTC2
VREF
“Open”
Connection when Current Amp is not used
MB3887
22
■PROCESSING WITHOUT USING OF THE ERROR AMP
When Error Amp is not used, leave FB1 terminal (pin 7) , FB2 terminal (pin 5) open and connect the −INE1
terminal (pin 8) and −INE2 terminal (pin 4) to GND and connect +INE1 terminal (pin 9) , and +INE2 terminal (pin
3) , to VREF.
9
5
8
4
7
+INE1 GND
+INE2
−INE1
−INE2
VREF
FB2
FB1
23
6
3
“Open”
Connection when Error Amp is not used
MB3887
23
■PROCESSING WITHOUT USING OF THE CS TERMINAL
When soft-start function is not used, leave the CS terminal (pin 22) open.
■NOTE ON AN EXTERNAL REVERSE-CURRENT PREVENTIVE DIODE
• Insert a rev erse-current prev entive diode at one of the three locations marked * to pre vent re verse current from
the battery.
• When selecting the re v erse current prev ention diode, be sure to consider the re v erse voltage (VR) and re v erse
current (IR) of the diode.
22
CS
“Open”
Connection when soft-start time is not specified
VCC(O)
OUT
VIN
VH
I1 RSBATT
Battery
A B
∗
∗
∗
21
20
19
MB3887
24
■APPLICATION EXAMPLE
A
B
Q1
Output voltage (Battery
voltage) is adjustable
D1
I1
Battery
R8
100 kΩ
C10
5600 pF
+
+ +
R9
10 kΩ
R14
1 kΩ
R10
30 kΩ
R11
30 kΩ
R7
22 kΩ
R18
200 kΩ
R19
100 kΩ
R17
100 kΩ
C6
1500 pF
C4
0.022 µF
R3
330 kΩ
R2
47 kΩC9
0.1 µF
C7
0.1 µF
C5
0.1 µF
C2
100 µFC3
100 µF
C1
22 µF
0.033 Ω
R1
22 µH
L1
R4
82 kΩ
R5
330 kΩ
R6
68 kΩ
R15
120 Ω
R16
200 kΩ
Q2
SW
R12
30 kΩ
R13
20 kΩ
C8
10000 pF
AB
AC Adaptor
IIN
VO
+
−−
+
8
10
13
12
9
+
−−
+
4
2
24
1
3
× 20
× 20
+
+
+
−
5
20
21
19
−
+
+
+
−
11
16
22
17 6 23
14
18
<Current Amp1>
7
VREF
<Current Amp2> VREF
VREF
VREF
VREF
5.0 V
4.2 V
10
µA
15 <SOFT>
2.5 V
1.5 V
<OUT>
<OSC>
Bias
Voltage
<VH>
<REF> <CTL>
<PWM Comp.>
Drive
VCC
(VCC − 6 V)
(VCC UVLO)
VCC VCC
CTL
215 kΩ
35 kΩ
0.91 V
(0.77 V)
VREF
UVLO
4.2 V
bias
−INC2
OUTD
FB2
OUTC2
VREF
−INE2
+INE2
+INE1
FB1
OUTC1
−INE1
−INC1
+INC2
GND
CS
VCC (O)
OUT
VH
RT
−INE3
FB3
+INC1
45 pF
<Error Amp1>
<Error Amp2>
<Error Amp3> <UVLO> VCC
VIN = 13.93 V to 25 V
(at 3 cell)
VIN = 17.65 V to 25 V
(at 4 cell)
Note:
Set output voltage so
that voltage applied to
OUTD terminal is 17 V or
less.
MB3887
25
■PARTS LIST
Note : VISHAY SILICONIX : VISHAY Intertechnology, Inc.
ROHM : ROHM CO., LTD.
TDK : TDK Corporation
SANYO : SANYO Electric Co., Ltd.
KYOCERA : Kyocera Corporation
MURATA : Murata Manufacturing Co., Ltd.
SEIDEN TECHNO : SEIDEN TECHNO CO., LTD.
KOA : KOA Corporation
ssm : SUSUMU Co., Ltd.
OS-CON is a trademark of SANYO Electric Co., Ltd.
COMPONENT ITEM SPECIFICATION VENDOR PARTS No.
Q1
Q2 P-ch FET
N-ch FET
VDS = −30 V, ID = ±8 A (Max)
VDS = 60 V, ID = 0.115 A
(Max)
VISHAY SILICONIX
VISHAY SILICONIX Si4435DY
2N7002E
D1 Diode VF = 0.42 V (Max) , IF = 3 A ROHM RB053L-30
L1 Inductor 22 µH3.5 A, 31.6
mΩTDK SLF12565T-
220M3R5
C1
C2, C3
C4
C5
C6
C7
C8
C9
C10
OS-CONTM
Electrolytic Condenser
Ceramics Condenser
Ceramics Condenser
Ceramics Condenser
Ceramics Condenser
Ceramics Condenser
Ceramics Condenser
Ceramics Condenser
22 µF
100 µF
0.022 µF
0.1 µF
1500 pF
0.1 µF
10000 pF
0.1 µF
5600 pF
25 V (10 %)
25 V (10 %)
50 V
16 V
10 V
25 V
10 V
16 V
10 V
SANYO
SANYO
TDK
KYOCERA
MURATA
MURATA
MURATA
KYOCERA
MURATA
25SL22M
25CV100AX
C1608JB1H223K
CM21W5R104K16
GRM39B152K10
GRM39F104KZ25
GRM39B103K10
CM21W5R104K16
GRM39B562K10
R1
R2
R3
R4
R5
R6
R7
R8
R9
R10 to R12
R13
R14
R15
R16, R18
R17, R19
Resistor
Resistor
Resistor
Resistor
Resistor
Resistor
Resistor
Resistor
Resistor
Resistor
Resistor
Resistor
Resistor
Resistor
Resistor
0.033 Ω
47 kΩ
330 kΩ
82 kΩ
330 kΩ
68 kΩ
22 kΩ
100 kΩ
10 kΩ
30 kΩ
20 kΩ
1 kΩ
120 Ω
200 kΩ
100 kΩ
1.0 %
0.5 %
0.5 %
0.5 %
0.5 %
0.5 %
0.5 %
0.5 %
1.0 %
0.5 %
0.5 %
0.5 %
0.5 %
0.5 %
0.5 %
SEIDEN TECHNO
KOA
KOA
KOA
KOA
KOA
KOA
KOA
KYOCERA
KOA
KOA
KOA
ssm
KOA
KOA
RK73Z1J-0D
RK73G1J-473D
RK73G1J-334D
RK73G1J-823D
RK73G1J-334D
RK73G1J-683D
RK73G1J-223D
RK73G1J-104D
CR21-103-F
RK73G1J-303D
RK73G1J-203D
RK73G1J-102D
RR0816P121D
RK73G1J-204D
RK73G1J-104D
MB3887
26
■REFERENCE DATA
(Continued)
100
98
96
94
92
90
88
86
84
82
80
10 m 100 m 1 10
Ta = +25 °C
VIN = 19 V
BATT charge voltage =
set at 12.6 V
SW = ON
Efficiency η (%) =
(VBATT × IBATT)
/ (VIN × IIN) × 100
100
98
96
94
92
90
88
86
84
82
80 0246810121416
Ta = +25 °C
VIN = 19 V
BATT charge voltage =
set at 12.6 V
SW = ON
Efficiency η (%) =
(VBATT × IBATT)
/ (VIN × IIN)
× 100
100
98
96
94
92
90
88
86
84
82
80
10 m 100 m 1 10
Ta = +25 °C
VIN = 19 V
BATT charge voltage =
set at 16.8 V
SW = ON
Efficiency η (%) =
(VBATT × IBATT)
/ (VIN × IIN) × 100
100
98
96
94
92
90
88
86
84
82
80 02468101214161820
Ta = +25 °C
VIN = 19 V
BATT charge voltage =
set at 16.8 V
SW = ON
Efficiency η (%) =
(VBATT × IBATT)
/ (VIN × IIN) × 100
Conversion efficiency vs. Charge current
(Constant voltage mode) Conversion efficiency vs. Charge current
(Constant current mode)
Conversion efficiency η (%)
BATT charge current IBATT (A)
Conversion efficiency η (%)
BATT charge voltage VBATT (V)
Conversion efficiency vs. Charge current
(Constant voltage mode) Conversion efficiency vs. Charge current
(Constant current mode)
Conversion efficiency η (%)
BATT charge current IBATT (A)
Conversion efficiency η (%)
BATT charge voltage VBATT (V)
MB3887
27
(Continued)
100
98
96
94
92
90
88
86
84
82
80
10 m 100 m 1 10
Ta = +25 °C
VIN = 19 V
BATT charge voltage =
set at 16.8 V
SW = ON
Efficiency η (%) =
(VBATT × IBATT)
/ (VIN × IIN) × 100
100
98
96
94
92
90
88
86
84
82
80 0 2 4 6 8101214161820
Ta = +25 °C
VIN = 19 V
BATT charge voltage =
set at 16.8 V
SW = ON
Efficiency η (%) =
(VBATT × IBATT)
/ (VIN × IIN) × 100
Conversion efficiency vs. Charge current
(Constant voltage mode) Conversion efficiency vs. Charge current
(Constant current mode)
Conversion efficiency η (%)
BATT charge current IBATT (A)
Conversion efficiency η (%)
BATT charge voltage VBATT (V)
18
16
14
12
10
8
6
4
2
001232.51.50.5 4 54.53.5
Dead Battery MODE DCC MODE
DCC : Dynamically-Controlled
Ta = +25 °C VIN = 19 V
BATT : Electronic load,
(Product of KIKUSUI PLZ-150W)
20
18
16
14
12
10
8
6
4
2
00 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5
Dead Battery MODE DCC MODE
DCC : Dynamically-Controlled
BATT : Electronic load,
(Product of KIKUSUI PLZ-150W)
Ta = +25 °C
VIN = 19 V
BATT voltage vs. BATT charge current
(set at 12.6 V)
BATT voltage VBATT (V)
BATT charge current IBATT (A)
BATT voltage vs. BATT charge current
(set at 16.8 V)
BATT voltage VBATT (V)
BATT charge current IBATT (A)
MB3887
28
(Continued)
100
0
−100
15
10
5
0
VBATT (mV)
VD (V)
Ta = +25 °C
VIN = 19 V
BATT = 1.5 A 98 mVp-p
012345678910
(µs)
VD
VBATT 100
0
−100
15
10
5
0
VBATT (mV)
VD (V)
Ta = +25 °C
VIN = 19 V
BATT = 3.0 A 98 mVp-p
VD
VBATT
012345678910
(µs)
100
0
−100
15
10
5
0
VBATT (mV)
VD (V)
Ta = +25 °C
VIN = 19 V
BATT = 1.5 A 58 mVp-p VBATT
012345678910
(µs)
VD
100
0
−100
15
10
5
0
VBATT (mV)
VD (V)
96 mVp-p
VD
VBATT
012345678910
(µs)
VIN = 19 V
BATT = 3.0 A
Ta = +25 °C
Switching waveform constant voltage mode
(set at 12.6 V) Switching waveform constant current mode
(set at 12.6 V, with 10 V)
Switching waveform constant voltage mode
(set at 16.8 V) Switching waveform constant current mode
(set at 16.8 V, with 10 V)
MB3887
29
(Continued)
20
10
0
4
2
0
5
0
VCTL (V)
VCS (V)
VBATT (V)
0 2 4 6 8 101214161820
(ms)
Ta = +25 °C, VIN = 19 V
BATT = 12 ΩVBATT
VCTL
ts = 10.4 ms VCS
20
10
0
4
2
0
5
0
VCTL (V)
VCS (V)
VBATT (V)
0 2 4 6 8 101214161820
(ms)
Ta = +25 °C
VIN = 19 V
BATT = 12 Ω
VBATT
VCTL
VCS
20
10
0
4
2
0
5
0
VCTL (V)
VCS (V)
VBATT (V)
0 2 4 6 8 101214161820
(ms)
VBATT
ts = 10.4 ms VCS
VCTL
Ta = +25 °C, VIN = 19 V
BATT = 12 Ω
20
10
0
4
2
0
5
0
VCTL (V)
VCS (V)
VBATT (V)
0 2 4 6 8 101214161820
(ms)
Ta = +25 °C
VIN = 19 V
BATT = 12 Ω
VBATT
VCTL
VCS
Soft-start operating waveform
constant voltage mode
(set at 12.6 V)
Discharge operating waveform
constant voltage mode
(set at 12.6 V)
Soft-start operating waveform
constant voltage mode
(set at 16.8 V)
Discharge operating waveform
constant voltage mode
(set at 16.8 V)
MB3887
30
■USAGE PRECAUTIONS
• Printed circuit board ground lines should be set up with consideration for common impedance.
• Take appropriate static electricity measures.
• Containers for semiconductor materials should hav e anti-static protection or be made of conductive material.
• After mounting, printed circuit boards should be stored and shipped in conductive bags or containers.
• Work platforms, tools, and instruments should be properly grounded.
• Working personnel should be grounded with resistance of 250 kΩ to 1 MΩ between body and ground.
• Do not apply negative voltages.
• The use of negative voltages below −0.3 V may create parasitic transistors on LSI lines, which can cause
malfunction.
■ORDERING INFORMATION
Part number Package Remarks
MB3887PFV 24-pin plastic SSOP
(FPT-24P-M03)
MB3887
31
■PACKAGE DIMENSION
24-pin plastic SSOP
(FPT-24P-M03) Note1: Pins width and pins thickness include plating thickness.
Note2: * This dimension does not include resin protrusion.
Dimensions in mm (inches) .
C
2001 FUJITSU LIMITED F24018S-c-3-4
7.75±0.10(.305±.004)
5.60±0.10 7.60±0.20
(.220±.004) (.299±.008)
*
0.10(.004)
112
1324
0.65(.026) –0.07
+0.08
0.24
.009 +.003
–.003 M
0.13(.005)
INDEX
0.17±0.03
(.007±.001)
"A"
0.25(.010)
0.10±0.10
(.004±.004)
(Stand off)
Details of "A" part
(Mounting height)
1.25 +0.20
–0.10
–.004
+.008
.049
0~8°
0.50±0.20
(.020±.008)
0.60±0.15
(.024±.006)
0.10(.004)
MB3887
FUJITSU LIMITED
All Rights Reserved.
The contents of this document are subject to change without notice.
Customers are advised to consult with FUJITSU sales
representatives before ordering.
The information and circuit diagrams in this document are
presented as examples of semiconductor device applications, and
are not intended to be incorporated in devices for actual use. Also,
FUJITSU is unable to assume responsibility for infringement of
any patent rights or other rights of third parties arising from the use
of this information or circuit diagrams.
The products described in this document are designed, developed
and manufactured as contemplated for general use, including
without limitation, ordinary industrial use, general office use,
personal use, and household use, but are not designed, developed
and manufactured as contemplated (1) for use accompanying fatal
risks or dangers that, unless extremely high safety is secured, could
have a serious effect to the public, and could lead directly to death,
personal injury, severe physical damage or other loss (i.e., nuclear
reaction control in nuclear facility, aircraft flight control, air traffic
control, mass transport control, medical life support system, missile
launch control in weapon system), or (2) for use requiring
extremely high reliability (i.e., submersible repeater and artificial
satellite).
Please note that Fujitsu will not be liable against you and/or any
third party for any claims or damages arising in connection with
above-mentioned uses of the products.
Any semiconductor devices have an inherent chance of failure. You
must protect against injury, damage or loss from such failures by
incorporating safety design measures into your facility and
equipment such as redundancy, fire protection, and prevention of
over-current levels and other abnormal operating conditions.
If any products described in this document represent goods or
technologies subject to certain restrictions on export under the
Foreign Exchange and Foreign Trade Law of Japan, the prior
authorization by Japanese government will be required for export
of those products from Japan.
F0211
FUJITSU LIMITED Printed in Japan