Fujitsu MB3887 User Manual

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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

PIN ASSIGNMENT

■

−INC2 :

OUTC2 :

+INE2 :

−INE2 :

FB2 :

VREF :

FB1 :

MB3887

(TOP VIEW)

: +INC2

: GND

: CS

: VCC (O)

: OUT

: VH

: VCC

−INE1 :

+INE1 :

OUTC1 :

OUTD :

−INC1 :

: RT

: −INE3

: FB3

: CTL

: +INC1

(FPT-24P-M03)

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.

BLOCK DIAGRAM

■

OUTC1

−INE1

+INC1

−INC1

+INE1

FB1

−INE2

13 12

7 4

+ × 20

−

VREF

− +

+ + +

−

<OUT>

Drive

MB3887

VCC (O)

OUT

OUTC2

+INC2

−INC2 +INE2

FB2

−INE3

OUTD

FB3

1 3

<SOFT>

VREF

+ × 20

−

10 µA

VREF

− +

VREF

− + +

4.2 V

45 pF

VCC

Bias

Voltage

<VH>

<UVLO>

(VCC UVLO)

4.2 V

<OSC>

17 6 23 RT

bias

VREF

2.5 V

1.5 V

0.91 V

(0.77 V)

VREF UVLO

VREF

5.0 V

CC − 6 V)

215 kΩ

35 kΩ

−

VCC

GND

VCC

18 14

VCC CTL

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.

■ 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

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

OUTD  0  17 V

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.

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]

Threshold voltage

VTHL 18

Hysteresis width V

Threshold voltage

VTHL 6VREF = 2.4 2.6 2.8 V

Hysteresis width V

Charge current I

Oscillation frequency

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

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.

3, 4,

8, 9

 0  VCC − 1.8 V

BW 5, 7 AV = 0 dB  2*  MHz

FBH 5, 7  4.7 4.9  V

VFBL 5, 7 20 200 mV

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

FBH 15  4.7 4.9  V

Output voltage

FBL 15 20 200 mV

Output source current

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

LEAK 11 OUTD = 17 V  01µA

ON 11 OUTD = 1 mA  35 50 Ω

12,

Input offset voltage V

+INC1 = +INC2 = −INC1

13,

= −INC2 = 3 V to VCC

−3 +3mV

+INC1 = +INC2 =

+INCH

13,

3 V to VCC, ∆V

IN = −100 mV

 20 30 µA

+INC1 = +INC2 =

Input current

−INCH 1, 12

+INCL

−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)

MB3887

Parameter

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

Sym-

bol

OUTC1 2, 10

OUTC2 2, 10

Current detection voltage

OUTC3 2, 10

OUTC4 2, 10

In-phase input voltage range

Voltage gain A

Frequency bandwidth

BW 2, 10 AV = 0 dB  2*  MHz

OUTCH 2, 10  4.7 4.9  V

Output voltage

(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

12, 13,

 0  V

CC V

+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

Output source current

Output sink current

Threshold voltage

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

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

5, 7,

Duty cycle = 0 % 1.4 1.5  V

5, 7,

Duty cycle = 100 %2.5 2.6 V

(Continued)

Parameter

Sym-

bol

MB3887

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

Pin No.

Conditions

Min Typ Max

Value

Unit

8. Output block [OUT]

9. Control block [CTL]

10. Bias voltage block [VH]

11. General

Output source current

Output sink current

Output ON resistor

SOURCE 20

SINK 20

ROH 20 OUT = −45 mA  6.5 9.8 Ω

OL 20 OUT = 45 mA  5.0 7.5 Ω

Rise time tr1 20

Fall time tf1 20

ON 14 IC Active mode 2  25 V

CTL input voltage

OFF 14 IC Standby mode 0  0.8 V

ICTLH 14 CTL = 5 V  100 150 µA

Input current

CTLL 14 CTL = 0 V  01µA

Output voltage V

Standby current I Power supply cur-

rent

H 19

CCS 18

ICC 18

OUT = 13 V, Duty ≤ 5 % (t = 1 / fOSC × Duty)

OUT = 19 V, Duty ≤ 5 % (t = 1 / fOSC × Duty)

OUT = 3300 pF (Si4435 × 1)

VCC = VCC (O) = 8 V to 25 V, VH = 0 to 30 mA

VCC = VCC (O) , CTL = 0 V

VCC = VCC (O) , CTL = 5 V

−400*  mA

 400*  mA

 50*  ns

VCC − 6.5 VCC − 6.0 VCC − 5.5 V

 010µA

 812mA

* : Standard design value

MB3887

TYPICAL CHARACTERISTICS

■

Power supply current vs. Power supply voltage

Ta = +25 °C

Power supply current ICC (mA)

0 5 10 15 20 25

Power supply voltage V

Reference voltage vs. I

REF load current

CTL = 5 V

CC (V)

Ta = +25 °C VCC = 19 V CTL = 5 V

Reference voltage VREF (V)

0 5 10 15 20 25 30

IREF load current IREF (mA)

Reference voltage vs. Power supply voltage

Reference voltage VREF (V)

0 5 10 15 20 25

Ta = +25 °C CTL = 5 V VREF = 0 mA

Power supply voltage VCC (V)

Reference voltage vs. Ambient temperature

5.08

5.06

5.04

5.02

5.00

4.98

4.96

4.94

Reference voltage VREF (V)

4.92

−40 −20 0 20 40 60 80 100

VCC = 19 V CTL = 5 V

Ambient temperature Ta ( °C)

CTL terminal current, Reference voltage

vs. CTL terminal voltage

1000

CTL terminal current ICTL (µA)

Ta = +25 °C

900

VCC = 19 V

800 700 600 500 400 300 200 100

0 5 10 15 20 25

VREF

ICTL

CTL terminal voltage VCTL (V)

10 9 8 7 6 5 4 3 2 1 0

Reference voltage VREF (V)

(Continued)

MB3887

Triangular wave oscillation frequency

vs. Timing resistor

1 M

OSC (Hz)

100 k

frequency f

Triangular wave oscillation

10 k

10 100 1000

Timing resistor RT (kΩ)

Triangular wave oscillation frequency

vs. Ambient temperature

320 315 310 305 300 295 290

OSC (kHz)

285 280 275 270

frequency f

265

Triangular wave oscillation

260

−40 −20 0 20 40 60 80 100

Ta = +25 °C VCC = 19 V CTL = 5 V

VCC = 19 V CTL = 5 V RT = 47 kΩ

Triangular wave oscillation frequency

vs. Power supply voltage

340 330 320 310

OSC (kHz)

300 290 280

frequency f

270

Triangular wave oscillation

260

0 5 10 15 20 25

Power supply voltage VCC (V)

Error amplifier threshold voltage

vs. Ambient temperature

4.25

2.24

4.23

2.22

4.21

TH (V)

4.20

4.19

4.18

voltage V

4.17

4.16

Error amplifier threshold

4.15

−40 −20 0 20 40 60 80 100

Ta = +25 °C CTL = 5 V RT = 47 kΩ

VCC = 19 V CTL = 5 V

Ambient temperature Ta ( °C)

(Continued)

MB3887

Error amplifier gain and phase vs. Frequency

Ta = +25 °C

180

−90

−180

Gain AV (dB)

−20

−40

1 k 10 k 100 k 1 M 10 M

Frequency f (Hz)

Error amplifier gain and phase vs. Frequency

Gain AV (dB)

−20

−40

Ta = +25 °C

180

−90

−180

Phase φ (deg)

10 kΩ

1 µF

10 kΩ

1 µF

10 kΩ

2.4 kΩ

10 kΩ10 kΩ

2.4 kΩ

10 kΩ10 kΩ

10 kΩ

4.2 V

(4)

(3)

4.2 V

16 22

VCC = 19 V

240 kΩ

−

Error Amp1

(Error Amp2)

VCC = 19 V

240 kΩ

− + +

Error Amp3

4.2 V

(5)

OUT

1 k 10 k 100 k 1 M 10 M

Frequency f (Hz)

Current detection amplifier gain and phase vs. Frequency

Gain AV (dB)

−20

−40

1 k 10 k 100 k 1 M 10 M

Ta = +25 °C

180

−90

−180

Phase φ (deg)

Frequency f (Hz)

(24)

(1)

12.55 V12.6 V

VCC = 19 V

×20

−

Current Amp1

(Current Amp2)

(2)

OUT

(Continued)

Power dissipation vs. Ambient temperature

800 740

700 600 500 400 300 200 100

Power dissipation PD (mW)

−40 −20 0 20 40 60 80 100

Ambient temperature Ta ( °C)

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 temperature-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 conver ter 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 (R terminal (pin 12) . Then it outputs the signal amplified by 20 times to the error amplifier (Error Amp1) at the next stage.

S) due to the flow of the charge current, using the +INC1 terminal (pin 13) and −INC1

MB3887

(7) PWM comparator block (PWM Comp.)

The PWM comparator circuit is a voltage-pulse width conver ter 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 v oltage b lock

(VH) . This results in increasing conversion efficiency and suppressing the withstand v oltage 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 Po wer OUTD

L OFF (Standby) Hi-Z

HON (Active) L

(10) Bias voltage block (VH)

The bias voltage circuit outputs V mode, this circuit outputs the potential equal to VCC.

CC −6 V (Typ) as the minimum potential of the output circuit. In the standby

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 v oltage of the under v oltage lock out 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

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 Ω, 1mA) of the inter nal FET connected to the OUTD terminal (pin 11) . In standby mode, the charging voltage is applied to OUTD termial. Therefore, output v oltage must be adjusted so that v oltage applied to OUTD terminal is 17 V or less.

Battery charging voltage : V

VO (V) = (R3 + R4) / R4 × 4.2 (V)

−INE3 16

OUTD

METHOD OF SETTING THE CHARGING CURRENT

■

− +

4.2 V

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 v alue attempts to flow, the charge voltage drops according to the set current v alue.

Battery charge current setting voltage : +INE1

+INE1 (V) = 20 × I1 (A) × R

S (Ω)

METHOD OF SETTING THE TRIANGULAR WAVE OSCILLATION FREQUENCY

■

The triangular wave oscillation frequency can be set b y the timing resistor (RT) connected the RT terminal (pin 17) .

Triangular wave oscillation frequency : f

OSC

fOSC (kHz) := 13630 / RT (kΩ)

MB3887

METHOD OF SETTING THE SOFT-START TIME

■

For pre venting 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 re v erse 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 conv erter output voltage goes up proportionately 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 %)

S (s) := 0.42 × CS (µF)

= 4.9 V = 4.2 V

= 0 V

Soft-start time: ts

FB3

−INE3 CS

VREF

10 µA 10 µA

CS terminal voltage Comparison with Error Amp block − INE3

voltage.

Error Amp3

− + +

4.2 V

UVLO

Soft-start circuit

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 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

VCC

OPERATION TIMING DIAGRAM

■

Error Amp2 FB2 Error Amp1 FB1

Error Amp2 FB3

R1 R2

−INE2

+INE2

−

2.5 V

OUT

Constant voltage control Constant current control

1.5 V

AC adapter dynamically-

controlled charging

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.

“Open”

+INC2

1312 24

−INC1 +INC1

−INC2

OUTC1

OUTC2

VREF

Connection when Current Amp is not used

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.

GND

“Open”

+INE1 +INE2

3 8

−INE1

−INE2

FB1

FB2

VREF

Connection when Error Amp is not used

PROCESSING WITHOUT USING OF THE CS TERMINAL

■

When soft-start function is not used, leave the CS terminal (pin 22) open.

MB3887

“Open”

Connection when soft-start time is not specified

NOTE ON AN EXTERNAL REVERSE-CURRENT PREVENTIVE DIODE

■

• Insert a reverse-current prev entive diode at one of the three locations marked * to pre vent re verse current from the battery.

• When selecting the rev erse current prev ention diode, be sure to consider the re v erse voltage (V

R) and reverse

current (IR) of the diode.

VCC(O)

OUT

VIN

∗

A B

∗

Battery

BATT

MB3887

APPLICATION EXAMPLE

■

AC Adaptor

0.033 Ω

Battery

100 µF

VIN = 13.93 V to 25 V

(at 3 cell)

IIN

VIN = 17.65 V to 25 V

(at 4 cell)

VCC (O)

VREF

−

0.1 µF

22 µF

<OUT>

+++

OUT

Drive

−

22 µH

VCC

VREF

+ +

−

CC − 6 V)

Bias

Voltage

100 µF

Output voltage (Battery

voltage) is adjustable

VCC

2.5 V

1.5 V

<VH>

<UVLO>

VREF

Note:

Set output voltage so

that voltage applied to

OUTD terminal is 17 V or

less.

35 kΩ

215 kΩ

−

0.91 V

(0.77 V)

VREF

UVLO

(VCC UVLO)

−

4.2 V

VCC

4.2 V

0.1 µF

CTL 14

<OSC>

VREF

5.0 V

bias

45 pF

17 6 23

GND

VREF

0.1 µF

47 kΩ

−INE1 OUTC1

100 kΩ

C10

× 20

−INC1

+INC1

10 kΩ

5600 pF

VREF

<SOFT>

µA

0.022 µF

−

R12

R14

+INE1

30 kΩ

1 kΩ

R13

R15

R16

−INE2

10000 pF

OUTC2

22 kΩ

FB1

20 kΩ

120 Ω

200 kΩ

−

× 20

−INC2

330 kΩ

+INE2

+INC2

82 kΩ

68 kΩ

R10

FB2

30 kΩ

R19

100 kΩ

R11

1500 pF

OUTD

R17

100 kΩ

330 kΩ

−INE3

R18

200 kΩ

30 kΩ

FB3

MB3887

PARTS LIST

■

COMPONENT ITEM SPECIFICATION VENDOR PARTS No.

Q1 Q2

D1 Diode VF = 0.42 V (Max) , IF = 3 A ROHM RB053L-30

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

L1 Inductor 22 µH C1

C2, C3

C4 C5 C6 C7 C8 C9

C10

R1 R2 R3 R4 R5 R6 R7 R8 R9

R10 to R12

R13 R14

R15 R16, R18 R17, R19

OS-CON

Electrolytic Condenser

Ceramics Condenser Ceramics Condenser Ceramics Condenser Ceramics Condenser Ceramics Condenser Ceramics Condenser Ceramics Condenser

Resistor Resistor Resistor Resistor Resistor Resistor Resistor Resistor Resistor Resistor Resistor Resistor Resistor Resistor Resistor

22 µF

100 µF

0.022 µF

0.1 µF

1500 pF

0.1 µF

10000 pF

0.1 µF

5600 pF

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

3.5 A, 31.6 mΩ

25 V (10 %) 25 V (10 %)

50 V 16 V 10 V 25 V 10 V 16 V 10 V

1.0 %

0.5 %

1.0 %

0.5 %

TDK

SANYO SANYO

TDK

KYOCERA

MURATA MURATA MURATA

KYOCERA

MURATA

SEIDEN TECHNO

KOA KOA KOA KOA KOA KOA KOA

KYOCERA

KOA KOA KOA

ssm KOA KOA

SLF12565T-

220M3R5 25SL22M

25CV100AX

C1608JB1H223K

CM21W5R104K16

GRM39B152K10

GRM39F104KZ25

GRM39B103K10

CM21W5R104K16

GRM39B562K10

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

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.

MB3887

REFERENCE DATA

■

Conversion efficiency vs. Charge current

(Constant voltage mode)

100

Ta = +25 °C

VIN = 19 V BATT charge voltage =

set at 12.6 V

SW = ON

Efficiency η (%) =

BATT × IBATT)

/ (V

88 86 84 82

Conversion efficiency η (%)

IN × IIN) × 100

10 m 100 m 1 10

BATT charge current IBATT (A)

Conversion efficiency vs. Charge current

(Constant voltage mode)

100

98 96 94 92 90 88 86 84 82

Conversion efficiency η (%)

10 m 100 m 1 10

Ta = +25 °C VIN = 19 V BATT charge voltage = set at 16.8 V SW = ON Efficiency η (%) =

BATT × IBATT)

(V / (V

IN × IIN) × 100

BATT charge current IBATT (A)

Conversion efficiency vs. Charge current

(Constant current mode)

100

Ta = +25 °C

VIN = 19 V

BATT charge voltage = set at 12.6 V

SW = ON

Efficiency η (%) =

BATT × IBATT)

/ (V

88 86 84 82

Conversion efficiency η (%)

IN × IIN)

× 100

0246810121416

BATT charge voltage VBATT (V)

Conversion efficiency vs. Charge current

(Constant current mode)

100

98 96 94 92 90 88 86 84 82

Conversion efficiency η (%)

02468101214161820

Ta = +25 °C VIN = 19 V BATT charge voltage = set at 16.8 V SW = ON Efficiency η (%) = (V

BATT × IBATT)

/ (V

IN × IIN) × 100

BATT charge voltage VBATT (V)

(Continued)

MB3887

Conversion efficiency vs. Charge current

(Constant voltage mode)

100

98 96 94 92 90 88 86 84 82

Conversion efficiency η (%)

10 m 100 m 1 10

Ta = +25 °C VIN = 19 V BATT charge voltage = set at 16.8 V SW = ON Efficiency η (%) =

BATT × IBATT)

(V / (VIN × IIN) × 100

BATT charge current IBATT (A)

BATT voltage vs. BATT charge current

(set at 12.6 V)

18 16 14 12 10

8 6 4

BATT voltage VBATT (V)

2 0

Dead Battery MODE DCC MODE

01232.51.50.5 4 54.53.5

Ta = +25 °C VIN = 19 V

BA TT : Electronic load, (Product of KIKUSUI PLZ-150W)

DCC : Dynamically-Controlled

BATT charge current IBATT (A)

Conversion efficiency vs. Charge current

(Constant current mode)

100

98 96 94 92 90 88 86 84 82

Conversion efficiency η (%)

0 2 4 6 8101214161820

Ta = +25 °C VIN = 19 V BATT charge voltage = set at 16.8 V SW = ON Efficiency η (%) = (V

BATT × IBATT)

/ (VIN × IIN) × 100

BATT charge voltage VBATT (V)

BATT voltage vs. BATT charge current

(set at 16.8 V)

20 18 16 14 12 10

8 6 4

BATT voltage VBATT (V)

2 0

Dead Battery MODE DCC MODE

0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5

BATT : Electronic load, (Product of KIKUSUI PLZ-150W)

Ta = +25 °C VIN = 19 V

DCC : Dynamically-Controlled

BATT charge current IBATT (A)

(Continued)

MB3887

Switching waveform constant voltage mode

(set at 12.6 V)

BATT (mV)

100

−100

D (V)

Ta = +25 °C VIN = 19 V BA TT = 1.5 A

98 mVp-p

15 10

5 0

012345678910

Switching waveform constant voltage mode

(set at 16.8 V)

Ta = +25 °C

VIN = 19 V BA TT = 1.5 A

58 mVp-p

VBATT

BATT (mV)

100

−100

D (V)

VBATT

(µs)

Switching waveform constant current mode

(set at 12.6 V, with 10 V)

BATT (mV)

100

−100

D (V)

Ta = +25 °C VIN = 19 V BA TT = 3.0 A

98 mVp-p

VBATT

15 10

5 0

012345678910

Switching waveform constant current mode

(set at 16.8 V, with 10 V)

Ta = +25 °C

VIN = 19 V

BA TT = 3.0 A

96 mVp-p

VBATT

BATT (mV)

100

−100

D (V)

(µs)

5 0

012345678910

(µs)

5 0

012345678910

(µs)

(Continued)

MB3887

BATT (V)

CS (V)

CTL (V)

BATT (V)

CS (V)

Soft-start operating waveform

constant voltage mode

(set at 12.6 V)

Ta = +25 °C, VIN = 19 V

BATT = 12 Ω 0 4

2 0

5 0

0 2 4 6 8 101214161820

ts = 10.4 ms

VBATT

VCTL

Soft-start operating waveform

constant voltage mode

(set at 16.8 V)

Ta = +25 °C, VIN = 19 V

BATT = 12 Ω 0 4

2 0

ts = 10.4 ms

VCS

VBATT

VCS

(ms)

BATT (V)

CS (V)

CTL (V)

BATT (V)

CS (V)

Discharge operating waveform

constant voltage mode

(set at 12.6 V)

20 10

0 4 2 0

VCTL

5 0

0 2 4 6 8 101214161820

VBATT

Ta = +25 °C VIN = 19 V BATT = 12 Ω

Discharge operating waveform

constant voltage mode

(set at 16.8 V)

20 10

0 4 2 0

VBATT

VCS

(ms)

VCS

CTL (V)

5 0

0 2 4 6 8 101214161820

VCTL

(ms)

CTL (V)

VCTL

5 0

0 2 4 6 8 101214161820

Ta = +25 °C VIN = 19 V BATT = 12 Ω

(ms)

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 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)

PACKAGE DIMENSION

■

MB3887

24-pin plastic SSOP

(FPT-24P-M03)

7.75±0.10(.305±.004)

1324

INDEX

112

0.65(.026)

0.24 .009

0.10(.004)

+0.08 –0.07

+.003 –.003

0.13(.005)

Note1: Pins width and pins thickness include plating thickness. Note2: * This dimension does not include resin protrusion.

5.60±0.10 7.60±0.20

(.220±.004) (.299±.008)

0.17±0.03

(.007±.001)

"A"

Details of "A" part

+0.20 –0.10

1.25

+.008 –.004

.049

0~8°

0.50±0.20

(.020±.008)

0.60±0.15

(.024±.006)

0.25(.010)

(Mounting height)

0.10±0.10

(.004±.004)

(Stand off)

2001 FUJITSU LIMITED F24018S-c-3-4

Dimensions in mm (inches) .

MB3887

FUJITSU LIMITED

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

Fujitsu MB3887 User Manual

Specifications and Main Features

Frequently Asked Questions

User Manual

DESCRIPTION

FEATURES

PACKAGE

PIN ASSIGNMENT

PIN DESCRIPTION

BLOCK DIAGRAM

ABSOLUTE MAXIMUM RATINGS

■ RECOMMENDED OPERATING CONDITIONS

ELECTRICAL CHARACTERISTICS

TYPICAL CHARACTERISTICS

FUNCTIONAL DESCRIPTION

SETTING THE CHARGING VOLTAGE

METHOD OF SETTING THE CHARGING CURRENT

METHOD OF SETTING THE TRIANGULAR WAVE OSCILLATION FREQUENCY

METHOD OF SETTING THE SOFT-START TIME

AC ADAPTOR VOLTAGE DETECTION

OPERATION TIMING DIAGRAM

PROCESSING WITHOUT USING THE CURRENT AMP

PROCESSING WITHOUT USING OF THE ERROR AMP

PROCESSING WITHOUT USING OF THE CS TERMINAL

NOTE ON AN EXTERNAL REVERSE-CURRENT PREVENTIVE DIODE

APPLICATION EXAMPLE

PARTS LIST

REFERENCE DATA

USAGE PRECAUTIONS

ORDERING INFORMATION

PACKAGE DIMENSION