Fujitsu Power Supply MB3887 User Manual

FUJITSU SEMICONDUCTOR  
DATA SHEET  
DS04-27709-3E  
ASSP For 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  
PIN ASSIGNMENT  
(TOP VIEW)  
INC2 :  
OUTC2 :  
+INE2 :  
INE2 :  
FB2 :  
1
2
3
4
5
6
7
8
9
24 : +INC2  
23 : GND  
22 : CS  
21 : VCC (O)  
20 : OUT  
19 : VH  
VREF :  
FB1 :  
18 : VCC  
17 : RT  
INE1 :  
+INE1 :  
16 : INE3  
15 : FB3  
14 : CTL  
13 : +INC1  
OUTC1 : 10  
OUTD : 11  
INC1 : 12  
(FPT-24P-M03)  
3
 
MB3887  
PIN DESCRIPTION  
Pin No.  
Symbol  
INC2  
OUTC2  
+INE2  
INE2  
FB2  
I/O  
I
Descriptions  
1
2
Current detection amplifier (Current Amp2) input terminal.  
Current detection amplifier (Current Amp2) output terminal.  
Error amplifier (Error Amp2) non-inverted input terminal.  
Error amplifier (Error Amp2) inverted input terminal.  
Error amplifier (Error Amp2) output terminal.  
O
I
3
4
I
5
O
O
O
I
6
VREF  
FB1  
Reference voltage output terminal.  
7
Error amplifier (Error Amp1) output terminal.  
8
INE1  
+INE1  
OUTC1  
Error amplifier (Error Amp1) inverted input terminal  
Error amplifier (Error Amp1) non-inverted input terminal.  
Current detection amplifier (Current Amp1) output terminal.  
9
I
10  
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.  
11  
OUTD  
O
12  
13  
INC1  
+INC1  
I
I
Current detection amplifier (Current Amp1) input terminal.  
Current detection amplifier (Current Amp1) input terminal.  
Power supply control terminal.  
14  
CTL  
I
Setting the CTL terminal at “L” level places the IC in the standby  
mode.  
15  
16  
FB3  
O
I
Error amplifier (Error Amp3) output terminal.  
INE3  
Error amplifier (Error Amp3) inverted input terminal.  
Triangular-wave oscillation frequency setting resistor connection  
terminal.  
17  
RT  
18  
19  
20  
21  
22  
23  
24  
VCC  
VH  
Power supply terminal for reference power supply and control circuit.  
Power supply terminal for FET drive circuit (VH = VCC 6 V) .  
External FET gate drive terminal.  
O
O
OUT  
VCC (O)  
CS  
Output circuit power supply terminal.  
Soft-start capacitor connection terminal.  
GND  
+INC2  
Ground terminal.  
I
Current detection amplifier (Current Amp2) input terminal.  
4
 
MB3887  
BLOCK DIAGRAM  
8
INE1  
OUTC1  
+INC1  
10  
13  
<Error Amp1>  
VREF  
<Current Amp1>  
+
× 20  
+
12  
9
INC1  
+INE1  
21 VCC (O)  
<PWM Comp.>  
<OUT>  
+
+
+
7
4
FB1  
20  
19  
Drive  
OUT  
VH  
INE2  
<Error Amp2>  
2
OUTC2  
<Current Amp2>  
VCC  
VREF  
24  
+
× 20  
+INC2  
+
Bias  
Voltage  
<VH>  
1
3
INC2  
+INE2  
(VCC 6 V)  
2.5 V  
1.5 V  
<UVLO>  
FB2 5  
<Error Amp3>  
VCC  
VREF  
(VCC UVLO)  
215 kΩ  
+
16  
11  
+
+
INE3  
35 kΩ  
OUTD  
4.2 V  
0.91 V  
(0.77 V)  
FB3  
CS  
15  
22  
VREF  
UVLO  
<SOFT>  
VREF  
10  
µA  
VCC  
4.2 V  
18  
14  
VCC  
CTL  
<OSC>  
<REF>  
VREF  
<CTL>  
45 pF  
5.0 V  
bias  
17  
RT  
6
23  
GND  
VREF  
5
 
MB3887  
ABSOLUTE MAXIMUM RATINGS  
Rating  
Parameter  
Symbol  
Conditions  
Unit  
Min  
Max  
28  
Power supply voltage  
Output current  
VCC  
IOUT  
VCC, VCC (O) terminal  
V
60  
mA  
Duty 5 %  
(t = 1 / fOSC × Duty)  
Peak output current  
IOUT  
700  
mA  
Power dissipation  
PD  
Ta +25 °C  
740*  
mW  
Storage temperature  
TSTG  
55  
+125  
°C  
* : 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.  
6
 
MB3887  
RECOMMENDED OPERATING CONDITIONS  
Value  
Typ  
Parameter  
Symbol  
Conditions  
Unit  
Min  
Max  
Power supply voltage  
VCC  
IREF  
IVH  
VCC, VCC (O) terminal  
8
25  
V
mA  
mA  
V
Reference voltage output  
current  
1  
0
0
30  
VH terminal output current  
INE1 to INE3, +INE1,  
+INE2 terminal  
VINE  
0
VCC 1.8  
Input voltage  
+INC1, +INC2, INC1,  
INC2 terminal  
VINC  
VOUTD  
IOUTD  
0
0
0
VCC  
17  
2
V
V
OUTD terminal  
output voltage  
OUTD terminal  
output current  
mA  
CTL terminal input voltage  
Output current  
VCTL  
IOUT  
0
25  
V
45  
+45  
mA  
Duty 5 %  
(t = 1 / fosc × Duty)  
Peak output current  
IOUT  
600  
+600  
mA  
Oscillation frequency  
Timing resistor  
fOSC  
RT  
100  
27  
290  
47  
500  
130  
1.0  
1.0  
kHz  
kΩ  
µF  
Soft-start capacitor  
VH terminal capacitor  
CS  
0.022  
0.1  
CVH  
µF  
Reference voltage output  
capacitor  
CREF  
0.1  
1.0  
µF  
°C  
Operating ambient  
temperature  
Ta  
30  
+25  
+85  
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.  
7
 
MB3887  
ELECTRICAL CHARACTERISTICS  
(Ta = +25 °C, VCC = 19 V, VCC (O) = 19 V, VREF = 0 mA)  
Value  
Sym- Pin  
Parameter  
Conditions  
Unit  
bol  
No.  
Min  
4.967  
4.95  
Typ  
5.000  
5.00  
3
Max  
5.041  
5.05  
10  
VREF1  
VREF2  
Line  
6
6
6
6
Ta = +25 °C  
V
V
Output voltage  
Ta = 10 °C to +85 °C  
VCC = 8 V to 25 V  
1.  
Reference  
voltage block  
[REF]  
Input stability  
Load stability  
mV  
mV  
Load  
VREF = 0 mA to 1 mA  
1
10  
Short-circuit output  
current  
Ios  
VTLH  
VTHL  
6
VREF = 1 V  
50  
6.2  
5.2  
25  
6.4  
5.4  
12  
6.6  
5.6  
mA  
V
VCC = VCC (O) ,  
VCC =  
18  
18  
Threshold voltage  
2.  
VCC = VCC (O) ,  
VCC =  
V
Under voltage  
lockout protec-  
tion circuit  
block  
Hysteresis width  
Threshold voltage  
Hysteresis width  
VH  
VTLH  
VTHL  
VH  
18 VCC = VCC (O)  
1.0*  
2.8  
2.6  
0.2  
V
V
V
V
6
6
6
VREF =  
VREF =  
2.6  
2.4  
3.0  
2.8  
[UVLO]  
3.  
Soft-start block Charge current  
[SOFT]  
ICS  
22  
14  
10  
6  
µA  
4.  
Oscillation  
frequency  
fOSC  
20 RT = 47 kΩ  
260  
290  
320  
kHz  
Triangular  
waveform os-  
cillator circuit  
block  
Frequency  
temperature  
stability  
f/fdt 20 Ta = 30 °C to +85 °C  
1*  
%
[OSC]  
3, 4,  
8, 9  
Input offset voltage  
Input bias current  
VIO  
FB1 = FB2 = 2 V  
1
5
mV  
nA  
3, 4,  
8, 9  
IB  
100  
30  
In-phase input  
voltage range  
3, 4,  
8, 9  
VCM  
AV  
0
VCC 1.8  
V
5-1.  
Error amplifier  
block  
[Error Amp1,  
Error Amp2]  
Voltage gain  
5, 7 DC  
100*  
2*  
dB  
Frequency  
bandwidth  
BW  
5, 7 AV = 0 dB  
MHz  
VFBH  
VFBL  
5, 7  
5, 7  
4.7  
4.9  
20  
V
Output voltage  
200  
mV  
Output source  
current  
ISOURCE 5, 7 FB1 = FB2 = 2 V  
ISINK 5, 7 FB1 = FB2 = 2 V  
2  
1  
mA  
Output sink current  
150  
300  
µA  
* : Standard design value.  
(Continued)  
8
 
MB3887  
(Ta = +25 °C, VCC = 19 V, VCC (O) = 19 V, VREF = 0 mA)  
Value  
Sym- Pin  
Parameter  
Conditions  
Unit  
bol  
No.  
Min  
Typ  
Max  
VTH1  
16 FB3 = 2 V, Ta = +25 °C 4.183  
FB3 = 2 V,  
4.200  
4.225  
V
V
Threshold voltage  
VTH2  
16  
4.169  
4.200  
4.231  
Ta = 10 °C to +85 °C  
Input current  
Voltage gain  
IINE3  
16 INE3 = 0 V  
100  
30  
nA  
dB  
AV  
15 DC  
100*  
Frequency  
bandwidth  
BW  
15 AV = 0 dB  
2*  
MHz  
5-2.  
Error amplifier  
block  
[Error Amp3]  
VFBH  
15  
15  
4.7  
4.9  
20  
V
Output voltage  
VFBL  
200  
mV  
Output source  
current  
ISOURCE 15 FB3 = 2 V  
2  
300  
0
1  
mA  
µA  
µA  
Output sink current  
ISINK  
ILEAK  
15 FB3 = 2 V  
150  
OUTD terminal  
output leak current  
11 OUTD = 17 V  
1
OUTD terminal  
output ON resistor  
RON  
VIO  
11 OUTD = 1 mA  
35  
50  
1,  
12, +INC1 = +INC2 = INC1  
13, = INC2 = 3 V to VCC  
24  
Input offset voltage  
3  
+3  
mV  
6.  
+INC1 = +INC2 =  
13,  
Current detec-  
tion amplifier  
block  
[Current  
Amp1, Current  
Amp2]  
I+INCH  
3 V to VCC,  
24  
20  
30  
µA  
µA  
VIN = 100 mV  
+INC1 = +INC2 =  
IINCH 1, 12 3 V to VCC,  
0.1  
0.2  
Input current  
Vin = 100 mV  
13, +INC1 = +INC2 = 0 V,  
24 Vin = 100 mV  
I+INCL  
180  
195  
120  
130  
µA  
µA  
+INC1 = +INC2 = 0 V,  
IINCL 1, 12  
Vin = 100 mV  
* : Standard design value  
(Continued)  
9
 
MB3887  
(Ta = +25 °C, VCC = 19 V, VCC (O) = 19 V, VREF = 0 mA)  
Value  
Sym- Pin  
bol No.  
Parameter  
Conditions  
Unit  
Min  
Typ  
Max  
+INC1 = +INC2 =  
VOUTC1 2, 10 3 V to VCC,  
1.9  
2.0  
2.1  
V
Vin = 100 mV  
+INC1 = +INC2 =  
VOUTC2 2, 10 3 V to VCC,  
0.34  
1.8  
0.40  
2.0  
0.46  
2.2  
V
V
V
Vin = 20 mV  
Current detection  
voltage  
+INC1 = +INC2 =  
VOUTC3 2, 10 0 V to 3 V,  
Vin = 100 mV  
+INC1 = +INC2 =  
VOUTC4 2, 10 0 V to 3 V,  
0.2  
0.4  
0.6  
Vin = 20 mV  
6.  
Current  
1,  
detection  
In-phase input  
voltage range  
12,  
13,  
24  
VCM  
0
VCC  
21  
V
amplifier block  
[CurrentAmp1,  
Current Amp2]  
+INC1 = +INC2 =  
Voltage gain  
AV  
2, 10 3 V to VCC,  
19  
20  
2*  
V/V  
Vin = 100 mV  
Frequency  
bandwidth  
BW 2, 10 AV = 0 dB  
MHz  
VOUTCH 2, 10  
4.7  
4.9  
20  
V
Output voltage  
VOUTCL 2, 10  
200  
mV  
Output source  
current  
ISOURCE 2, 10 OUTC1 = OUTC2 = 2 V  
2  
300  
1.5  
1  
mA  
µA  
V
Output sink cur-  
rent  
ISINK  
2, 10 OUTC1 = OUTC2 = 2 V  
150  
1.4  
7.  
PWM  
5, 7,  
15  
VTL  
Duty cycle = 0 %  
comparator  
block  
[PWM Comp.]  
Threshold voltage  
5, 7,  
15  
VTH  
Duty cycle = 100 %  
2.5  
2.6  
V
* : Standard design value  
(Continued)  
10  
 
MB3887  
(Continued)  
(Ta = +25 °C, VCC = 19 V, VCC (O) = 19 V, VREF = 0 mA)  
Value  
Sym- Pin  
Parameter  
Output source  
Conditions  
Unit  
bol  
No.  
Min  
Typ  
Max  
OUT = 13 V, Duty 5 %  
(t = 1 / fOSC × Duty)  
ISOURCE  
20  
400*  
mA  
mA  
current  
Output sink  
current  
OUT = 19 V, Duty 5 %  
(t = 1 / fOSC × Duty)  
ISINK  
20  
400*  
8.  
ROH  
ROL  
20 OUT = 45 mA  
20 OUT = 45 mA  
6.5  
5.0  
9.8  
7.5  
Output ON  
resistor  
Output block  
[OUT]  
OUT = 3300 pF  
20  
Rise time  
Fall time  
tr1  
tf1  
50*  
50*  
ns  
ns  
(Si4435 × 1)  
OUT = 3300 pF  
20  
(Si4435 × 1)  
VON  
VOFF  
ICTLH  
ICTLL  
14 IC Active mode  
14 IC Standby mode  
14 CTL = 5 V  
2
0
25  
0.8  
150  
1
V
V
CTL input voltage  
Input current  
9.  
Control block  
[CTL]  
100  
0
µA  
µA  
14 CTL = 0 V  
10.  
Bias voltage  
block  
VCC = VCC (O)  
19 = 8 V to 25 V,  
VH = 0 to 30 mA  
Output voltage  
Standby current  
VH  
VCC 6.5 VCC 6.0 VCC 5.5  
V
[VH]  
VCC = VCC (O) ,  
CTL = 0 V  
ICCS  
ICC  
18  
0
8
10  
12  
µA  
11.  
General  
Power supply cur-  
rent  
VCC = VCC (O) ,  
CTL = 5 V  
18  
mA  
* : Standard design value  
11  
 
MB3887  
TYPICAL CHARACTERISTICS  
Power supply current vs. Power supply voltage  
Reference voltage vs. Power supply voltage  
6
6
Ta = +25 °C  
CTL = 5 V  
5
4
3
2
1
0
5
4
3
2
Ta = +25 °C  
CTL = 5 V  
1
VREF = 0 mA  
0
0
5
10  
15  
20  
25  
0
5
10  
15  
20  
25  
Power supply voltage VCC (V)  
Power supply voltage VCC (V)  
Reference voltage vs. IREF load current  
Reference voltage vs. Ambient temperature  
6
5
4
3
2
1
0
5.08  
Ta = +25 °C  
VCC = 19 V  
CTL = 5 V  
VCC = 19 V  
5.06  
CTL = 5 V  
5.04  
5.02  
5.00  
4.98  
4.96  
4.94  
4.92  
0
5
10  
15  
20  
25  
30  
40 20  
0
20  
40  
60  
80  
100  
IREF load current IREF (mA)  
Ambient temperature Ta ( °C)  
CTL terminal current, Reference voltage  
vs. CTL terminal voltage  
1000  
900  
800  
700  
600  
500  
400  
300  
200  
100  
0
10  
9
8
7
6
5
4
3
2
1
0
Ta = +25 °C  
VCC = 19 V  
VREF  
ICTL  
0
5
10  
15  
20  
25  
CTL terminal voltage VCTL (V)  
(Continued)  
12  
 
MB3887  
Triangular wave oscillation frequency  
vs. Timing resistor  
Triangular wave oscillation frequency  
vs. Power supply voltage  
1 M  
100 k  
10 k  
340  
330  
320  
310  
300  
290  
280  
270  
260  
Ta = +25 °C  
VCC = 19 V  
CTL = 5 V  
Ta = +25 °C  
CTL = 5 V  
RT = 47 kΩ  
0
5
10  
15  
20  
25  
10  
100  
1000  
Timing resistor RT (k)  
Power supply voltage VCC (V)  
Triangular wave oscillation frequency  
vs. Ambient temperature  
Error amplifier threshold voltage  
vs. Ambient temperature  
320  
315  
310  
305  
300  
295  
290  
285  
280  
275  
270  
265  
260  
4.25  
2.24  
4.23  
2.22  
4.21  
4.20  
4.19  
4.18  
4.17  
4.16  
4.15  
VCC = 19 V  
CTL = 5 V  
VCC = 19 V  
CTL = 5 V  
RT = 47 kΩ  
40  
20  
0
20  
40  
60  
80  
100  
40 20  
0
20  
40  
60  
80  
100  
Ambient temperature Ta ( °C)  
Ambient temperature Ta ( °C)  
(Continued)  
13  
 
MB3887  
Error amplifier gain and phase vs. Frequency  
Ta = +25 °C  
40  
20  
180  
90  
VCC = 19 V  
AV  
4.2 V  
φ
240 kΩ  
10 kΩ  
1 µF  
10 kΩ  
+
8
(4)  
0
0
+
2.4 kΩ  
IN  
7
(5)  
OUT  
9
(3)  
20  
40  
90  
180  
Error Amp1  
(Error Amp2)  
10 kΩ  
10 kΩ  
1 k  
10 k  
100 k  
1 M  
10 M  
Frequency f (Hz)  
Error amplifier gain and phase vs. Frequency  
Ta = +25 °C  
VCC = 19 V  
4.2 V  
40  
20  
180  
90  
AV  
240 kΩ  
10 kΩ  
φ
10 kΩ  
1 µF  
+
16  
22  
+
+
0
0
2.4 kΩ  
10 kΩ  
IN  
15  
OUT  
20  
40  
90  
180  
Error Amp3  
4.2 V  
10 kΩ  
1 k  
10 k  
100 k  
1 M  
10 M  
Frequency f (Hz)  
Current detection amplifier gain and phase vs. Frequency  
Ta = +25 °C  
VCC = 19 V  
40  
20  
180  
90  
AV  
13  
(24)  
+
×20  
10  
(2)  
φ
12  
(1)  
OUT  
Current Amp1  
(Current Amp2)  
0
0
12.6 V  
12.55 V  
20  
40  
90  
180  
1 k  
10 k  
100 k  
1 M  
10 M  
Frequency f (Hz)  
(Continued)  
14  
 
MB3887  
(Continued)  
Power dissipation vs. Ambient temperature  
800  
740  
700  
600  
500  
400  
300  
200  
100  
0
40 20  
0
20  
40  
60  
80  
100  
Ambient temperature Ta ( °C)  
15  
 
MB3887  
FUNCTIONAL DESCRIPTION  
1. DC/DC Converter Unit  
(1) Reference voltage block (Ref)  
The reference voltage generator uses the voltage supplied from the VCC terminal (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 reference voltage VREF  
terminal (pin 6) .  
(2) Triangular wave oscillator block (OSC)  
The triangular wave oscillator builds the capacitor for frequency setting into, and generates the triangular wave  
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) Error 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 feedback 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 voltage from the DC/DC converter and outputs the PWM  
control signal. External output voltage setting resistors can be connected to the error amplifier inverted 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  
terminal (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 next  
stage.  
16  
 
MB3887  
(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 triangular 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” level sets the output amplitude to 6 V (Typ) using the voltage generated by the bias voltage block  
(VH) .  
This results in increasing conversion efficiency and suppressing the withstand voltage of the connected external  
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  
CTL  
L
Power  
OUTD  
Hi-Z  
L
OFF (Standby)  
ON (Active)  
H
(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  
reference voltage drop and fixes the OUT terminal (pin 20) to the “H” level. The system restores voltage supply  
when the supply voltage or internal reference voltage reaches the threshold voltage of the under voltage lockout  
protection circuit.  
Protection circuit (UVLO) operation function table  
When UVLO is operating (VCC or VREF voltage is lower than UVLO threshold voltage.)  
OUTD  
OUT  
CS  
Hi-Z  
H
L
17  
 
MB3887  
3. Soft-Start Function  
Soft-start block (SOFT)  
Connecting a 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, 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 external voltage setting resistors (R3,  
R4) to the INE3 terminal (pin 16) . Be sure to select a resistor value that allows you to ignore the on-resistor  
(35 , 1mA) of the internal FET connected to the OUTD terminal (pin 11) . In standby mode, the charging  
voltage is applied to OUTD termial. Therefore, output voltage must 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)  
VO  
B
R3  
R4  
<Error Amp3>  
INE3  
16  
11  
+
+
4.2 V  
OUTD  
22  
CS  
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 ()  
METHOD OF SETTING THE TRIANGULAR WAVE OSCILLATION FREQUENCY  
Thetriangularwaveoscillationfrequencycanbesetbythetimingresistor(RT)connectedtheRTterminal(pin17).  
Triangular wave oscillation frequency : fOSC  
fOSC (kHz) =: 13630 / RT (k)  
18  
 
MB3887  
METHOD OF SETTING THE SOFT-START TIME  
For preventing rush current upon activation of IC, the IC allows soft-start using the capacitor (Cs) connected to  
the CS terminal (pin 22) .  
When CTL terminal (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 terminal (pin 15) ) is determined by comparison between the lower voltage of the two  
non-reverse input terminals (4.2 V and CS terminal voltage) and reverse input terminal voltage (INE3 terminal  
(pin 16) voltage) . Within the soft-start period (CS terminal voltage < 4.2 V) , FB3 is determined by comparison  
between INE3 terminal voltage and CS terminal voltage, and DC/DC converter 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)  
CS terminal voltage  
= 4.9 V  
= 4.2 V  
Comparison with Error Amp block INE3  
voltage.  
= 0 V  
Soft-start time: ts  
VREF  
10 µA  
10 µA  
15  
16  
22  
FB3  
Error  
Amp3  
+
+
INE3  
CS  
4.2 V  
Q2  
UVLO  
CS  
Soft-start circuit  
19  
 
MB3887  
AC ADAPTOR VOLTAGE DETECTION  
• With an external resistor connected to the +INE2 terminal (pin 3) , the IC enters the dynamically-controlled  
charging mode to reduce the charge current to keep AC adapter power constant when the partial 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  
<Error Amp2>  
INE2  
4
3
+
A
VCC  
+INE2  
R1  
R2  
OPERATION TIMING DIAGRAM  
Error Amp2 FB2  
Error Amp1 FB1  
2.5 V  
1.5 V  
Error Amp2 FB3  
OUT  
AC adapter dynamically-  
controlled charging  
Constant voltage control  
Constant current control  
20  
 
MB3887  
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 terminal (pin 1) to VREF, and then leave OUTC1 terminal (pin 10) and OUTC2 terminal  
(pin 2) open.  
12  
1
13  
24  
INC1  
INC2  
+INC1  
+INC2  
10  
2
OUTC1  
OUTC2  
“Open”  
6
VREF  
Connection when Current Amp is not used  
21  
 
MB3887  
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.  
23  
GND  
9
3
+INE1  
+INE2  
8
4
INE1  
INE2  
7
5
FB1  
FB2  
“Open”  
6
VREF  
Connection when Error Amp is not used  
22  
 
MB3887  
PROCESSING WITHOUT USING OF THE CS TERMINAL  
When soft-start function is not used, leave the CS terminal (pin 22) open.  
“Open”  
22  
CS  
Connection when soft-start time is not specified  
NOTE ON AN EXTERNAL REVERSE-CURRENT PREVENTIVE DIODE  
• Insert a reverse-current preventive diode at one of the three locations marked * to prevent reverse current from  
the battery.  
• When selecting the reverse current prevention diode, be sure to consider the reverse voltage (VR) and reverse  
current (IR) of the diode.  
VIN  
VCC(O)  
21  
A
B
OUT  
20  
19  
I1  
BATT  
RS  
VH  
Battery  
23  
 
MB3887  
APPLICATION EXAMPLE  
24  
 
MB3887  
PARTS LIST  
COMPONENT  
ITEM  
SPECIFICATION  
VENDOR  
PARTS No.  
VDS = 30 V, ID = ±8 A (Max)  
VDS = 60 V, ID = 0.115 A  
(Max)  
Q1  
Q2  
P-ch FET  
N-ch FET  
VISHAY SILICONIX  
VISHAY SILICONIX  
Si4435DY  
2N7002E  
D1  
L1  
Diode  
Inductor  
VF = 0.42 V (Max) , IF = 3 A  
ROHM  
TDK  
RB053L-30  
3.5 A, 31.6  
SLF12565T-  
220M3R5  
22 µH  
mΩ  
C1  
C2, C3  
C4  
C5  
C6  
C7  
C8  
C9  
C10  
OS-CONTM  
22 µF  
100 µF  
0.022 µF  
0.1 µF  
25 V (10 %)  
25 V (10 %)  
50 V  
SANYO  
SANYO  
TDK  
KYOCERA  
MURATA  
MURATA  
MURATA  
KYOCERA  
MURATA  
25SL22M  
25CV100AX  
Electrolytic Condenser  
Ceramics Condenser  
Ceramics Condenser  
Ceramics Condenser  
Ceramics Condenser  
Ceramics Condenser  
Ceramics Condenser  
Ceramics Condenser  
C1608JB1H223K  
CM21W5R104K16  
GRM39B152K10  
GRM39F104KZ25  
GRM39B103K10  
CM21W5R104K16  
GRM39B562K10  
16 V  
10 V  
25 V  
10 V  
16 V  
10 V  
1500 pF  
0.1 µF  
10000 pF  
0.1 µF  
5600 pF  
R1  
R2  
R3  
R4  
R5  
R6  
R7  
R8  
R9  
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  
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  
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  
KOA  
KOA  
KOA  
KOA  
KOA  
KOA  
KYOCERA  
KOA  
R10 to R12  
R13  
R14  
R15  
R16, R18  
R17, R19  
KOA  
KOA  
ssm  
KOA  
120 Ω  
200 kΩ  
100 kΩ  
KOA  
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.  
25  
 
MB3887  
REFERENCE DATA  
Conversion efficiency vs. Charge current  
(Constant voltage mode)  
Conversion efficiency vs. Charge current  
(Constant current mode)  
100  
98  
96  
94  
92  
90  
88  
86  
84  
82  
80  
100  
98  
96  
94  
92  
90  
88  
86  
84  
82  
80  
Ta = +25 °C  
VIN = 19 V  
Ta = +25 °C  
VIN = 19 V  
BATT charge voltage =  
set at 12.6 V  
BATT charge voltage =  
set at 12.6 V  
SW = ON  
SW = ON  
Efficiency η (%) =  
(VBATT × IBATT)  
/ (VIN × IIN) × 100  
Efficiency η (%) =  
(VBATT × IBATT)  
/ (VIN × IIN)  
× 100  
10 m  
100 m  
1
10  
0
2
4
6
8
10  
12  
14  
16  
BATT charge current IBATT (A)  
BATT charge voltage VBATT (V)  
Conversion efficiency vs. Charge current  
(Constant voltage mode)  
Conversion efficiency vs. Charge current  
(Constant current mode)  
100  
98  
96  
94  
92  
90  
88  
86  
84  
82  
80  
100  
98  
96  
94  
92  
90  
88  
86  
84  
82  
80  
Ta = +25 °C  
VIN = 19 V  
Ta = +25 °C  
VIN = 19 V  
BATT charge voltage =  
set at 16.8 V  
BATT charge voltage =  
set at 16.8 V  
SW = ON  
Efficiency η (%) =  
(VBATT × IBATT)  
/ (VIN × IIN) × 100  
SW = ON  
Efficiency η (%) =  
(VBATT × IBATT)  
/ (VIN × IIN) × 100  
0
2
4
6
8
10 12 14 16 18 20  
10 m  
100 m  
1
10  
BATT charge current IBATT (A)  
BATT charge voltage VBATT (V)  
(Continued)  
26  
 
MB3887  
Conversion efficiency vs. Charge current  
Conversion efficiency vs. Charge current  
(Constant voltage mode)  
(Constant current mode)  
100  
98  
96  
94  
92  
90  
88  
86  
84  
82  
80  
100  
98  
96  
94  
92  
90  
88  
86  
84  
82  
80  
Ta = +25 °C  
VIN = 19 V  
Ta = +25 °C  
VIN = 19 V  
BATT charge voltage =  
BATT charge voltage =  
set at 16.8 V  
SW = ON  
Efficiency η (%) =  
(VBATT × IBATT)  
/ (VIN × IIN) × 100  
set at 16.8 V  
SW = ON  
Efficiency η (%) =  
(VBATT × IBATT)  
/ (VIN × IIN) × 100  
10 m  
100 m  
1
10  
0
2
4
6
8
10 12 14 16 18 20  
BATT charge current IBATT (A)  
BATT charge voltage VBATT (V)  
BATT voltage vs. BATT charge current  
(set at 16.8 V)  
BATT voltage vs. BATT charge current  
(set at 12.6 V)  
20  
18  
16  
14  
12  
10  
8
18  
16  
14  
12  
10  
8
Ta = +25 °C VIN = 19 V  
BATT : Electronic load,  
BATT : Electronic load,  
(Product of KIKUSUI PLZ-150W)  
(Product of KIKUSUI PLZ-150W)  
Ta = +25 °C  
VIN = 19 V  
Dead Battery MODE  
DCC MODE  
Dead Battery MODE  
DCC MODE  
6
6
4
4
2
2
DCC : Dynamically-Controlled  
DCC : Dynamically-Controlled  
2.5 3.5 4.5  
0
0
0
0.5  
1
1.5  
2
3
4
5
0
0.5  
1
1.5  
2
2.5  
3
3.5  
4
4.5  
5
BATT charge current IBATT (A)  
BATT charge current IBATT (A)  
(Continued)  
27  
 
MB3887  
Switching waveform constant voltage mode  
(set at 12.6 V)  
Switching waveform constant current mode  
(set at 12.6 V, with 10 V)  
Ta = +25 °C  
VBATT (mV)  
100  
Ta = +25 °C  
VIN = 19 V  
VBATT (mV)  
100  
VIN = 19 V  
98 mVp-p  
98 mVp-p  
VBATT  
BATT = 1.5 A  
VBATT  
VD  
BATT = 3.0 A  
0
0
VD  
100  
VD (V)  
15  
100  
VD (V)  
15  
10  
5
10  
5
0
0
0
1
2
3
4
5
6
7
8
9
10  
(µs)  
0
1
2
3
4
5
6
7
8
9
10  
(µs)  
Switching waveform constant voltage mode  
(set at 16.8 V)  
Switching waveform constant current mode  
(set at 16.8 V, with 10 V)  
Ta = +25 °C  
Ta = +25 °C  
VBATT (mV)  
VBATT (mV)  
VIN = 19 V  
58 mVp-p  
VIN = 19 V  
BATT = 3.0 A  
100  
100  
BATT = 1.5 A  
96 mVp-p  
VBATT  
VD  
VBATT  
VD  
0
0
100  
VD (V)  
15  
100  
VD (V)  
15  
10  
5
10  
5
0
0
0
1
2
3
4
5
6
7
8
9
10  
(µs)  
0
1
2
3
4
5
6
7
8
9
10  
(µs)  
(Continued)  
28  
 
MB3887  
(Continued)  
Soft-start operating waveform  
constant voltage mode  
(set at 12.6 V)  
Discharge operating waveform  
constant voltage mode  
(set at 12.6 V)  
VBATT (V)  
VBATT (V)  
20  
20  
10  
0
VBATT  
VCS  
Ta = +25 °C, VIN = 19 V  
BATT = 12 Ω  
10  
VBATT  
VCS  
0
VCS (V)  
4
VCS (V)  
4
ts = 10.4 ms  
2
0
2
0
Ta = +25 °C  
VIN = 19 V  
BATT = 12 Ω  
VCTL (V)  
5
VCTL (V)  
5
VCTL  
VCTL  
0
0
0
2
4
6
8
10 12 14 16 18 20  
(ms)  
0
2
4
6
8
10 12 14 16 18 20  
(ms)  
Discharge operating waveform  
constant voltage mode  
(set at 16.8 V)  
Soft-start operating waveform  
constant voltage mode  
(set at 16.8 V)  
VBATT (V)  
20  
VBATT (V)  
20  
Ta = +25 °C, VIN = 19 V  
BATT = 12 Ω  
VBATT  
VCS  
10  
10  
VBATT  
0
VCS (V)  
4
0
VCS (V)  
4
ts = 10.4 ms  
2
0
2
0
VCS  
Ta = +25 °C  
VIN = 19 V  
BATT = 12 Ω  
VCTL (V)  
5
VCTL (V)  
5
VCTL  
VCTL  
0
0
0
2
4
6
8
10 12 14 16 18 20  
(ms)  
0
2
4
6
8
10 12 14 16 18 20  
(ms)  
29  
 
MB3887  
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 have 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 kto 1 Mbetween 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  
MB3887PFV  
Package  
Remarks  
24-pin plastic SSOP  
(FPT-24P-M03)  
30  
 
MB3887  
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.  
0.17±0.03  
(.007±.001)  
*
7.75±0.10(.305±.004)  
24  
13  
5.60±0.10 7.60±0.20  
(.220±.004) (.299±.008)  
INDEX  
Details of "A" part  
1.25 +0.20  
–0.10  
(Mounting height)  
.049 +.008  
–.004  
0.25(.010)  
0~8°  
"A"  
1
12  
0.24 +0.08  
.009 +.003  
–0.07  
0.65(.026)  
M
0.13(.005)  
–.003  
0.50±0.20  
0.10±0.10  
(.020±.008)  
(.004±.004)  
(Stand off)  
0.60±0.15  
(.024±.006)  
0.10(.004)  
C
2001 FUJITSU LIMITED F24018S-c-3-4  
Dimensions in mm (inches) .  
31  
 
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  
 

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