Fujitsu MB3887 User Manual

FUJITSU SEMICONDUCTOR

DATA SHEET

DS04-27709-3E

ASSP F or Pow er 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 batter y’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, f or example, with the A C 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

(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

2

PIN ASSIGNMENT

■

−INC2 :

OUTC2 :

+INE2 :

−INE2 :

FB2 :

VREF :

FB1 :

MB3887

(TOP VIEW)

: +INC2

1

2

3

4

5

6

7

24

: GND

23

: CS

22

: VCC (O)

21

: OUT

20

: VH

19

: VCC

18

−INE1 :

+INE1 :

OUTC1 :

OUTD :

−INC1 :

10

11

12

: RT

8

9

17

16

15

14

13

: −INE3

: FB3

: CTL

: +INC1

(FPT-24P-M03)

3

MB3887

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.

With IC in standby mode, this terminal is set to “Hi-Z” to prevent loss

11 OUTD O

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.

Power supply control terminal.
14 CTL I

15 FB3 O Error amplifier (Error Amp3) output terminal.
16 −INE3 I Error amplifier (Error Amp3) inverted input terminal.

17 RT 
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.

Setting the CTL terminal at “L” level places the IC in the standby

mode.

Triangular-wave oscillation frequency setting resistor connection

terminal.

4

BLOCK DIAGRAM

■

OUTC1

−INE1

+INC1

−INC1

+INE1

FB1

−INE2

8

10

<Current Amp1>

13
12

9

7
4

+
× 20

−

<Error Amp1>

VREF

−
+

<PWM Comp.>

+
+
+

−

<OUT>

Drive

MB3887

21

VCC (O)

20

OUT

OUTC2

+INC2

−INC2
+INE2

FB2

−INE3

OUTD

FB3

CS

2

<Current Amp2>

24

1
3

5

16

11

15

<SOFT>

VREF

22

+
× 20

−

10
µA

<Error Amp2>

VREF

−
+

<Error Amp3>

VREF

−
+
+

4.2 V

45 pF

VCC

Bias

Voltage

<VH>

<UVLO>

(VCC UVLO)

4.2 V

<OSC>

17 6 23
RT

<REF> <CTL>

bias

VREF

2.5 V

1.5 V

0.91 V

(0.77 V)

VREF
UVLO

VREF

5.0 V

(V

CC − 6 V)

215 kΩ

+

35 kΩ

−

VCC

GND

VCC

19

18
14

VH

VCC
CTL

5

MB3887

ABSOLUTE MAXIMUM RATINGS

■

Parameter Symbol Conditions

Unit

Min Max

Rating

Power supply voltage V

CC VCC, VCC (O) terminal  28 V

Output current IOUT 60 mA
Peak output current I
Power dissipation P

OUT

D Ta ≤ +25 °C  740* mW

Duty ≤ 5 %
(t = 1 / f

OSC × Duty)

 700 m A

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

■ RECOMMENDED OPERATING CONDITIONS

MB3887

Parameter Symbol Conditions

Unit

Min Typ Max

Value

Power supply voltage V
Reference voltage output

current
VH terminal output current I

CC VCC, VCC (O) terminal 8  25 V

IREF

VH

V

INE

−INE1 to −INE3, +INE1,
+INE2 terminal





−1  0mA

0  30 mA
0  VCC − 1.8 V

Input voltage

+INC1, +INC2, −INC1,

−INC2 terminal

0  VCC V

OUTD terminal
output voltage

OUTD terminal
output current

VINC

V

OUTD  0  17 V

I

OUTD  0  2mA

CTL terminal input voltage VCTL  0  25 V
Output current I

Peak output current I

OUT −45 +45 mA

OUT

Duty ≤ 5 %
(t = 1 / fosc × Duty)

−600 +600 mA

Oscillation frequency fOSC  100 290 500 kHz
Timing resistor R
Soft-start capacitor C
VH terminal capacitor C
Reference voltage output

capacitor
Operating ambient

temperature

T  27 47 130 kΩ
S 0.022 1.0 µF

VH 0.1 1.0 µF

CREF 0.1 1.0 µF

Ta −30 +25 +85 °C

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

■

Parameter

Output voltage

1.
Reference
voltage block
[REF]

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

(Ta = +25 °C, VCC = 19 V, VCC (O) = 19 V, VREF = 0 mA)

Sym-

bol

V
V

Pin
No.

REF1 6Ta = +25 °C 4.967 5.000 5.041 V
REF2 6Ta = −10 °C to +85 °C 4.95 5.00 5.05 V

Conditions

Min Typ Max

Value

Ios 6 VREF = 1 V −50 −25 −12 mA

Unit

2.
Under voltage
lockout protec­tion circuit
block
[UVLO]

3.
Soft-start block
[SOFT]

4.
Triangular
waveform os­cillator circuit
block
[OSC]

V

Threshold voltage

VTHL 18

Hysteresis width V

V

Threshold voltage

VTHL 6VREF = 2.4 2.6 2.8 V

Hysteresis width V

Charge current I

Oscillation
frequency

f

Frequency
temperature

∆f/fdt 20 Ta = −30 °C to +85 °C  1* %

stability

Input offset voltage V

Input bias current I

TLH 18

H 18 VCC = VCC (O)  1.0*  V

TLH 6VREF = 2.6 2.8 3.0 V

H 6 0.2  V

CS 22 −14 −10 −6 µA

OSC 20 RT = 47 kΩ 260 290 320 kHz

IO

B

VCC = VCC (O) ,
VCC =

VCC = VCC (O) ,
VCC =

3, 4,

FB1 = FB2 = 2 V  15mV

8, 9

3, 4,

8, 9

−100 −30  nA

6.2 6.4 6.6 V

5.2 5.4 5.6 V

In-phase input

5-1.
Error amplifier
block
[Error Amp1,
Error Amp2]

voltage range
Voltage gain AV 5, 7 DC  100*  dB
Frequency

bandwidth

Output voltage

Output source
current

Output sink current I

* : Standard design value.

8

3, 4,

V

CM

8, 9

 0  VCC − 1.8 V

BW 5, 7 AV = 0 dB  2*  MHz

FBH 5, 7  4.7 4.9  V

V

VFBL 5, 7 20 200 mV

I

SOURCE 5, 7 FB1 = FB2 = 2 V −2 −1mA

SINK 5, 7 FB1 = FB2 = 2 V 150 300 µA

(Continued)

MB3887

(Ta = +25 °C, VCC = 19 V, VCC (O) = 19 V, VREF = 0 mA)

Parameter

Threshold voltage

Sym-

bol

V
V

Pin
No.

TH1 16 FB3 = 2 V, Ta = +25 °C 4.183 4.200 4.225 V
TH2 16

Conditions

FB3 = 2 V,
Ta = −10 °C to +85 °C

Min Typ Max

4.169 4.200 4.231 V

Input current IINE3 16 −INE3 = 0 V −100 −30  nA

Value

Unit

5-2.
Error amplifier
block
[Error Amp3]

6.
Current detec­tion amplifier
block
[Current
Amp1, Current
Amp2]

Voltage gain A
Frequency

bandwidth

V 15 DC  100*  dB

BW 15 AV = 0 dB  2*  MHz

V

FBH 15  4.7 4.9  V

Output voltage

V

FBL 15 20 200 mV

Output source
current

I

SOURCE 15 FB3 = 2 V −2 −1mA

Output sink current ISINK 15 FB3 = 2 V 150 300 µA
OUTD terminal

output leak current
OUTD terminal

output ON resistor

I

LEAK 11 OUTD = 17 V  01µA

R

ON 11 OUTD = 1 mA  35 50 Ω

1,

12,

Input offset voltage V

IO

+INC1 = +INC2 = −INC1

13,

= −INC2 = 3 V to VCC

−3 +3mV

24

+INC1 = +INC2 =

I

+INCH

13,

24

3 V to VCC,
∆V

IN = −100 mV

 20 30 µA

+INC1 = +INC2 =

I

Input current

−INCH 1, 12

I

+INCL

I

−INCL 1, 12

3 V to VCC,
∆Vin = −100 mV

13, 24+INC1 = +INC2 = 0 V,

∆Vin = −100 mV
+INC1 = +INC2 = 0 V,

∆Vin = −100 mV

 0.1 0.2 µA

−180 −120 µA

−195 −130 µA

* : Standard design value

(Continued)

9

MB3887

Parameter

6.
Current
detection
amplifier block
[Current Amp1,
Current Amp2]

Sym-

bol

V

OUTC1 2, 10

V

OUTC2 2, 10

Current detection
voltage

V

OUTC3 2, 10

V

OUTC4 2, 10

In-phase input
voltage range

V

Voltage gain A

Frequency
bandwidth

BW 2, 10 AV = 0 dB  2*  MHz

V

OUTCH 2, 10  4.7 4.9  V

Output voltage

V

(Ta = +25 °C, VCC = 19 V, VCC (O) = 19 V, VREF = 0 mA)

Pin
No.

Conditions

Min Typ Max

Value

Unit

+INC1 = +INC2 =
3 V to VCC,

1.9 2.0 2.1 V

∆Vin = −100 mV
+INC1 = +INC2 =

3 V to VCC,

0.34 0.40 0.46 V

∆Vin = −20 mV
+INC1 = +INC2 =

0 V to 3 V,

1.8 2.0 2.2 V

∆Vin = −100 mV
+INC1 = +INC2 =

0 V to 3 V,

0.2 0.4 0.6 V

∆Vin = −20 mV

1,

CM

12,
13,

 0  V

CC V

24

+INC1 = +INC2 =

V 2, 10

3 V to VCC,

19 20 21 V/V

∆Vin = −100 mV

OUTCL 2, 10 20 200 mV

7.
PWM
comparator
block
[PWM Comp.]

* : Standard design value

10

Output source
current

Output sink cur­rent

Threshold voltage

I

SOURCE 2, 10 OUTC1 = OUTC2 = 2 V −2 −1mA

ISINK 2, 10 OUTC1 = OUTC2 = 2 V 150 300 µA

5, 7,

V

TL

TH

V

Duty cycle = 0 % 1.4 1.5  V

15

5, 7,

Duty cycle = 100 %2.5 2.6 V

15

(Continued)