Fujitsu MB3878 User Manual

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FUJITSU SEMICONDUCTOR

DATA SHEET

DS04-27706-2E

ASSP

For Power Supply Applications (Secondary battery)

DC/DC Converter IC for Charging

MB3878

DESCRIPTION

■■■■

The MB3878 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 adaptor in order to keep its power constant (dynamically-controlled charging). The charging method enables quick charging, f or example, with the A C adaptor during operation of a notebook PC The MB3878 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 adaptor and dynamically controlling the charge current (Dynamically-controlled charging)

• Output voltage setting using external resistor : 1 cell to 4 cells

• High efficiency : 94 %

• Wide range of operating supply voltages : 7 V to 25 V

• Output voltage setting accuracy : 4.2V ± 0.8% (per cell)

• Built-in frequency setting capacitor enables frequency setting using external resistor only

• Oscillator frequency range : 100kHz to 500kHz

PACKAGE

■■■■

24-pin plastic SSOP

(FPT-24P-M03)

(Continued)

MB3878

(Continued)

• Built-in current detector 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

• Built-in totem-pole output stage supporting P-channel MOS FETs devices

PIN ASSIGNMENT

■■■■

(TOP VIEW)

: +INC2

−INC2 :

OUTC2 :

+INE2 :

: GND

: CS

−INE2 :

FB2 :

VREF :

FB1 :

−INE1 :

+INE1 :

OUTC1 :

OUTD :

−INC1 :

: VCC (O)

: OUT

: VH

: VCC

: RT

: −INE3

: FB3

: CTL

: +INC1

(FPT-24P-M03)

PIN DESCRIPTION

■■■■

Pin No. Symbol I/O Descriptions

1 −INC2 I Current detection amplifier (Current Amp. 2) input pin. 2 OUTC2 O Current detection amplifier (Current Amp. 2) output pin. 3 +INE2 I Error amplifier (Error Amp. 2) non-inverted input pin. 4 −INE2 I Error amplifier (Error Amp. 2) inverted input pin. 5 FB2 O Error amplifier (Error Amp. 2) output pin. 6 VREF O Reference voltage output pin. 7 FB1 O Error amplifier (Error Amp. 1) output pin. 8 −INE1 I Error amplifier (Error Amp. 1) inverted input pin 9 +INE1 I Error amplifier (Error Amp. 3) non-inverted input pin.

10 OUTC1 O Current detection amplifier (Current Amp. 1) output pin.

With IC in standby mode, this pin is left open to prevent loss of current

11 OUTD O

12 −INC1 I Current detector amplifier (Current Amp. 1) input pin.

through output voltage setting resistance. Set CTL pin to “H” level and OUTD pin to “L” level.

MB3878

13 +INC1 I Current detector amplifier (Current Amp. 1) input pin. 14 CTL I 15 FB3 O Error amplifier (Error Amp. 3) output pin.

16 −INE3 I Error amplifier (Error Amp. 3) inverted input pin. 17 RT  Triangular-wave oscillation frequency setting resistor connection pin. 18 VCC  Power supply pin for reference power supply and control circuit. 19 VH O Power supply pin for FET drive circuit (VH = Vcc − 5 V). 20 OUT O High-side FET gate drive pin. 21 VCC (O)  Output circuit power supply pin. 22 CS  Soft-start capacitor connection pin. 23 GND  Ground pin. 24 +INC2 I Current detection amplifier (Current Amp. 2) input pin.

Power supply control pin. Setting the CTL pin low places the IC in the standby mode.

MB3878

BLOCK DIAGRAM

■■■■

−INE1

OUTC1

+INC1

−INC1

+INE1

FB1

−INE2

13 12

9 7

+ × 25

−

− +

VREF

+ + +

−

<OUT>

Drive

VCC (O)

OUT

OUTC2

+INC2

−INC2 +INE2

FB2

−INE3

OUTD

FB3

1 3

<SOFT>

VREF

+ × 25

−

1 µA

− +

− + +

4.2 V

VREF

(45 pF)

(VCC UVLO)

bias

<OSC>

17 6 23 RT

VREF

VCC

Bias

Voltage

<VH>

<UVLO>

0.91 V

(0.77 V)

VREF UVLO

VREF

5.0 V

2.5 V

1.5 V

215 kΩ

35 kΩ

−

VCC

GND

CC − 5 V)

VCC

18 14

VCC CTL

ABSOLUTE MAXIMUM RAGINGS

■■■■

MB3878

Parameter Symbol Conditions

Unit

Min Max

Power supply voltage VCC VCC, VCC (O)  28 V

Rating

Output current I Peak output current I

OUT 60 mA OUT Duty ≤ 5 % (t = 1 / fOSC × Duty)  500 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.

RECOMMENDED OPERATING CONDITIONS

■■■■

Value

Parameter

Symbol

Conditions

Min Typ Max

Power supply voltage V

Reference voltage output

current

VH pin output current I

CC VCC, VCC (O) 7  25 V

REF −1  0mA

VH  0  30 mA

VINE −INE1 to −INE3, +INE1, +INE2 0  VCC − 1.8 V

Input voltage

INC +INC1, +INC2, −INC1, −INC2 0  VCC V

Unit

OUTD pin output voltage V

OUTD pin output current I

OUTD  0  17 V

OUTD  0  2mA

CTL pin input voltage VCTL  0  25 V

output current I

Peak output current I

OUT −45  45 mA OUT Duty ≤ 5 % (t = 1 / fosc × Duty) −450  450 mA

Oscillator frequency fOSC  100 290 500 kHz

Timing resistor R

Soft-start capacitor C

T  33 47 130 kΩ S 2200 100000 pF

VH pin capacitor CVH 0.1 1.0 µF

Reference voltage output

capacitor

REF 0.1 1.0 µF

Operating ambient temperature 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.

MB3878

ELECTRICAL CHARACTERISTICS

■■■■

Parameter Symbol

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

Pin No.

Conditions

Min Typ Max

Value

Unit

Reference

voltage block

(Ref)

Under voltage

lockout protection

circuit block

(UVLO)

Soft-start block

(SOFT)

Triangular

waveform

oscillator circuit

block (OSC)

Output voltage V

REF 6

Ta = −30 °C to +85 °C 4.945 5.000 5.055 V Input stability Line 6 VCC = 7 V to 25 V  310mV Load stability Load 6 VREF = 0 mA to −1 mA  110mV

Ta = +25 °C 4.995 5.000 5.045 V

Short-circuit output current

Ios 6 VREF = 1 V −25 −15 −5mA

TLH 18

VCC = VCC (O) ,

VCC =

6.1 6.4 6.7 V

Threshold voltage

THL 18

VCC = VCC (O) ,

VCC =

5.1 5.4 5.7 V

Hysteresis width VH 18 VCC = VCC (O) 0.7 1.0 1.3 V

TLH 6VREF = 2.6 2.8 3.0 V

Threshold voltage

THL 6VREF = 2.4 2.6 2.8 V

Hysteresis width VH 6VH = VTLH − VTHL 0.05 0.20 0.35 V Charge current I Oscillation

frequency

CS 22 −1.3 −0.8 −0.5 µA

OSC 20 RT = 47 kΩ 260 290 320 kHz

Frequency temperature

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

stability Input offset

voltage

3, 4,

FB1 = FB2 = 2 V  15mV

8, 9

Error amplifier block (Error Amp.1, Error Amp.2)

* : Standard design value.

Input bias current I Common mode

input voltage

range Voltage gain A Frequency

bandwidth

Output voltage

VFBL 5, 7 20 200 mV

Output source current

Output sink current

SOURCE 5, 7 FB1 = FB2 = 2 V −2.0 −0.6 mA

3, 4,

8, 9

3, 4,

8, 9

V 5, 7 DC  100*  dB

W 5, 7 AV = 0 dB  2.0*  MHz

FBH 5, 7  4.7 4.9  V

SINK 5, 7 FB1 = FB2 = 2 V 150 300 µA

−100 −30  nA

 0 

VCC −

1.8

(Continued)

Parameter Symbol

TH1 16 FB3 = 2 V, Ta = +25 °C 4.167 4.200 4.233 V

Threshold voltage

TH2 16

Input current I

INE3 16 −INE3 = 0 V −100 −30  nA

MB3878

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

Pin No.

Conditions

FB3 = 2 V, Ta = −30 °C to +85 °C

Min Typ Max

4.158 4.200 4.242 V

Value

Unit

Error amplifier block (Error Amp.3)

Current detection amplifier block (Current Amp.1, Current Amp.2)

Voltage gain A Frequency

bandwidth

Output voltage

Output source current

Output sink current

OUTD pin output leak current

OUTD pin output ON resistor

SOURCE 15 FB3 = 2 V −2.0 −0.6 mA

ISINK 15 FB3 = 2 V 150 300 µA I

+INCH

−INCH

Input current

+INCL

−INCL

OUTC1

OUTC2

Current detection voltage

OUTC3

OUTC4

Common mode input voltage

VCM

range

V 15 DC  100*  dB

W 15 AV = 0 dB  2.0*  MHz

FBH 15  4.7 4.9  V

FBL 15 20 200 mV

LEAK 11 OUTD = 16.8 V  01µA

ON 11 OUTD = 1 mA  70 100 Ω

+INC1 = +INC2 = 12.7 V,

13,

−INC1 = −INC2 = 12.6 V

+INC1 = +INC2 = 12.7 V,

−INC1 = −INC2 = 12.6 V

+INC1 = +INC2 = 0.1 V,

13,

−INC1 = −INC2 = 0 V

+INC1 = +INC2 = 0.1 V,

−INC1 = −INC2 = 0 V

+INC1 = +INC2 = 12.7 V,

−INC1 = −INC2 = 12.6 V

+INC1 = +INC2 = 12.63 V,

−INC1 = −INC2 = 12.6 V

+INC1 = +INC2 = 0.1 V,

−INC1 = −INC2 = 0 V

+INC1 = +INC2 = 0.03 V,

−INC1 = −INC2 = 0 V

 10 20 µA

 0.1 0.2 µA

−130 −65 µA

−140 −70 µA

2.25 2.5 2.75 V

0.50 0.75 1.00 V

1.25 2.50 3.75 V

0.125 0.750 1.375 V

1, 12, 13,

 0  Vcc V

24 Voltage gain A Frequency

bandwidth

* : Standard design value.

+INC1 = +INC2 = 12.7 V,

−INC1 = −INC2 = 12.6 V

AV = 0 dB  2.0*  MHz

22.5 25 27.5 V/V

(Continued)

MB3878

(Continued)

Parameter Symbol

Current detection amplifier block (Current Amp.1, Current Amp.2)

PWM comparator block (PWM Comp.)

Output voltage

Output source current

Output sink current

Threshold voltage

Output source current

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

Pin No.

OUTCH 2, 10  4.7 4.9  V

OUTCL 2, 10 20 200 mV

SOURCE 2, 10 OUTC1 = OUTC2 = 2 V −2.0 −0.6 mA

Conditions

Min Typ Max

Value

Unit

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

5, 7,

SOURCE 20

Duty cycle = 0 % 1.4 1.5  V

5, 7,

Duty cycle = 100 %2.5 2.6 V

OUT = 11 V, Duty ≤ 5 % (t = 1 / fOSC × Duty)

−200*  mA

Output block (OUT)

Control block (CTL)

Bias voltage block (VH)

General

Output sink current

Output ON resistor

SINK 20

OH 20 OUT = −45 mA  8.0 12.0 Ω

ROL 20 OUT = 45 mA  6.5 9.7 Ω

Rise time tr1 20

Fall time tf1 20

ON 14 Active mode 2  25 V

CTL input voltage

VOFF 14 Standby mode 0  0.8 V

CTLH 14 CTL = 5 V  100 200 µA

Input current

CTLL 14 CTL = 0 V  01µA

Output voltage VH 19

Standby current I Power supply

current

CCS

18, 19VCC = VCC (O) ,

OUT = 16 V, Duty ≤ 5 % (t = 1 / fOSC × Duty)

OUT = 3300 pF

(equivalent to Si4435 × 1)

OUT = 3300 pF

(equivalent to Si4435 × 1)

VCC = VCC (O) = 7 V to 25 V, VH = 0 to 30 mA

CTL = 0 V

CTL = 5 V

 200*  mA

 70*  ns

 60*  ns

VCC −

5.5

VCC −

5.0

VCC −

4.5

 010µA

 8.0 12.0 mA

* : Standard design value

TYPICAL CHARACTERISTICS

■■■■

MB3878

Power supply current vs. power supply voltage

CC (mA)

Power supply current

0 5 10 15 20 25

Power supply voltage V

Ta = +25 °C CTL = 5 V

CC (V)

Reference voltage vs. VREF load current

Ta = +25 °C VCC = 19 V CTL = 5 V

Reference voltage VREF (V)

0 5 10 15 20 25 30

VREF 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

2.0

1.5

1.0

0.5

0.0

−0.5

−1.0

−1.5

Reference voltage ∆VREF (%)

−2.0

−40 −20 0 20 40 60 80 100

VCC = 19 V CTL = 5 V VREF = 0 mA

Ambient temperature Ta ( °C)

Reference voltage vs. CTL pin voltage

Ta = +25 °C VCC = 19 V VREF = 0 mA

Reference voltage VREF (V)

0 0.5 1 1.5 2 2.5

CTL pin voltage VCTL (V)

CTL pin current vs. CTL pin voltage

1.0 Ta = +25 °C VCC = 19 V

0.8

0.6

0.4

0.2

CTL pin current ICTL (mA)

0.0

0 5 10 15 20 25

CTL pin voltage VCTL (V)

(Continued)

MB3878

Triangular wave oscillator frequency vs.

timing resistor

1 M

100 k

OSC (Hz)

10 k

Triangular wave oscillator frequency

10 k 100 k 1 M

Timing resistor R

Triangular wave oscillator frequency

340 330 320 310 300 290

OSC (kHz)

280 270 260

frequency f

250

Triangular wave oscillator

240

−40 −20 0 20 40 60 80 100

Ta = +25 °C VCC = 19 V CTL = 5 V

T (Ω)

VCC = 19 V CTL = 5 V RT = 47 kΩ

Triangular wave oscillator frequency vs.

power supply voltage

340 330 320 310 300 290 280

OSC (kHz)

270 260 250 240

Triangular wave oscillator frequency

0 5 10 15 20 25

Power supply voltage VCC (V)

Error amplifier threshold voltage vs. ambient temperature (Error Amp.3)

5.0

4.0

3.0

2.0

1.0

0.0

−1.0

−2.0

−3.0

−4.0

−5.0

−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)

Error amplifier threshold voltage ∆VTH (%)

Ambient temperature Ta ( °C)

(Continued)

MB3878

Error amplifier gain and phase vs. frequency

Gain AV (dB)

−20

−40

1 k 10 k 100 k 1 M 10 M

Ta = +25 °C

Frequency f (Hz)

Current detection amplifier gain and phase

vs. frequency

Gain AV (dB)

−20

−40

Ta = +25 °C

180

−90

−180

180

−90

−180

Phase φ (deg)

1 µF

−+

5.2 V

10 kΩ

2.4 kΩ

10 kΩ

VCC = 19 V

240 kΩ

−

(4)

(3)

2.5 V

VCC = 19 V

(24)

×25

−

12 (1)

12.55 V12.6 V

OUT

(5)

Error Amp.1

(Error Amp.2)

OUT 10 (2)

Current Amp.1

(Current Amp.2)

1 k 10 k 100 k 1 M 10 M

Frequency f (Hz)

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)

MB3878

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 (5.0V Typ) used as the reference supply voltage for the IC’s internal circuitry.

This pin 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 b uilds the capacitor for frequency setting into, and generates the triangular wave oscillator 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 Amp.1)

This amplifier detects the output signal from the current detector ampifier (Current amp .1), 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 -INE terminal (pin 8), providing stable phase compensation to the system.

(4) Error amplifier block (Error Amp.2)

This amplifier (Error Amp.2) detects voltage pendency of the AC adaptor 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 Amp.3)

This error amplifier (Error Amp. 3) 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 inverse input pin 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 surge 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 detector amplifier block (Current Amp.1)

The current detection amplifier (Current Amp.1) detects a voltage drop which occurs between both ends of the output sense resistor (R

−INC1 terminal (pin 12). Then it outputs the signal amplified by 25 times to the error amplifier (Error Amp.1) at the next stage.

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

MB3878

(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 Amp. 1 to Error Amp. 3) 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 5 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.)

(10) Bias voltage block (VH)

The bias voltage circuit outputs Vcc − 5 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 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.

3. Soft-start Function

Soft-start block (SOFT)

Connecting a capacitor to the CS terminal (pin 22) prevents surge 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 of the DC/DC converter.

MB3878

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. Be sure to select a resistor value that allows you to ignore the on resistor (70 Ω, 1mA) of the internal FET connected to the OUTD terminal (pin 11).

Battery charging voltage: V

VO (V) = (R3 + R4) / R4 × 4.2 (V)

−INE3 16

OUTD

< Error Amp.3 >

− +

4.2 V

METHOD OF SETTING THE CHARGING CURRENT

■■■■

The charge current (output control current) value can be set with the voltage at the +INE1 terminal (pin 9). If a current exceeding the set value attempts to flo w , the charge v oltage drops according to the set current value. Battery charge current setting voltage : +INE1 +INE1 (V) = 25 × I1 (A) × R

METHOD OF SETTING THE SOFT-START TIME

■■■■

S (Ω)

Upon activation, the IC starts charging the capacitor (Cs) connected to the CS terminal (pin 22). The error amplifier causes soft-start operation to be performed with the output voltage in proportion to the CS

terminal voltage regardless of the load current of the DC/DC converter. Soft-start time: ts (Time taken for the output voltage to reach 100 %) ts (s) := 4.2 × C

METHOD OF SETTING THE TRIANGULAR WAVE OSCILLATOR FREQUENCY

■■■■

S (µF)

The trianguar wave oscillator frequency can be set b y the timing resistor (RT) connected the RT terminal (pin 17). Triangular wave oscillator frequency: f

OSC

fOSC (kHz) := 13630 / RT (kΩ)

MB3878

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 adaptor po wer constant when the partial potential point A of the AC adaptor voltage (Vcc) becomes lower than the voltage at the -INE2 terminal.

AC adaptor detected voltage setting: Vth Vth (V) = (R1 + R2) / R2 × −INE2

−INE2 setting voltage range : 1.176 V to 4.2 V (equivalent to 7 V to 25 V for Vcc)

VCC

OPERATION TIMING DIAGRAM

■■■■

Error Amp.1 Error Amp.3 Error Amp.2

FB1 FB3 FB2

R1 R2

−INE2

+INE2

−

2.5 V

1.5 V

OUT

AC adaptor dynamicallycontrolled charging

Constant voltage control

Constant current control

AC adaptor dynamicallycontrolled charging

MB3878

PROCESSING WITHOUT USE OF THE CS PIN

■■■■

If the soft-start function is not used, the CS terminal (pin 22) should be left open.

Open

When no soft-start time is 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

APPLICATION EXAMPLE 1

■■■■

AC Adaptor

A B

VIN

IIN

22 µF

−

BATT

0.033 Ω

12 µH

Battery

+ +

MB3878

100 µF

−

100 µF

Output voltage (Battery voltage) is adjustable

0.1 µF SW OFF : Dead Battery MODE

Range of input voltage

VIN=13V to 21V(at Load = 3A)

<Error

−INE1 OUTC1

100 kΩ

C10 5600 pF

VREF

−

Amp.1>

× 25

+INC1

−INC1

10 kΩ

VCC (O)

−

+INE1

R12

30 kΩ

R14

1.3 kΩ

OUT

0.1 µF 20

Drive

<OUT>

−

+++

FB1

−INE2

10000 pF

R13

30 kΩ

R15

110 Ω

Bias

VCC

VREF

−

<Error

Amp.2>

−

× 25

30 kΩ

+INC2

R11

82 kΩ

−INC2

30 kΩ

OUTC2

R10

− 5 V)

<VH>

Voltage

+INE2

330 kΩ

VCC

CTL

VCC

2.5 V

1.5 V

<UVLO>

<Error

FB2

22 kΩ

68 kΩ

215 kΩ

(VCC UVLO)

VREF

−

Amp.3>

R17

100 kΩ

−INE3

R18

200 kΩ

1500 pF

35 kΩ

−

0.91 V

(0.77 V)

4.2 V

OUTD

330 kΩ

VREF

<SOFT>

FB3

UVLO

1 µA

VREF

VCC

bias

<OSC>

2200 pF

Note : SW ON : DCC MODE

GND

VREF

5.0 V

(45 pF)

VREF

17 6 23

0.1 µF

47 kΩ

R16

200 kΩ

MB3878

PARTS LIST (for APPLICATION EXAMPLE 1)

■■■■

COMPONENT ITEM SPECIFICATION VENDOR PARTS No.

VISHAY Q1 Q2

D1 Diode MBRS130LT3 MOTOROLA MBRS130LT3 L1 Coil 12 µH 4.0 A, 38 mΩ SUMIDA CDRH124-12 µH

FET FET

Si4435DY

2N7002

SILICONIX

VISHAY

SILICONIX

Si4435DY

2N7002

C2, C3

C5 C6 C7 C8 C9

C10

RT R3 R4 R5 R6 R7 R8 R9

R10 to R13

R14 R15 R16 R17 R18

OS Condenser

OS 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

2200 pF

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

1.3 kΩ 110 Ω

200 kΩ 100 kΩ 200 kΩ

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

10 %

16 V

10 %

25 V

10 %

16 V

10 %

1.0 %

0.5 %

1.0 %

0.5 %

0.5 % 5 %

0.5 %



Note VISHAY SILICONIX : VISHAY Intertechnology, Inc.

MOTOROLA : Motorola Japan Ltd. SUMIDA : SUMIDA ELECTRIC CO., Ltd.

REFERENCE DATA

■■■■

MB3878

100

Conversion efficiency η (%)

BATT voltage VBATT (V)

BATT (V)

CTL (V)

20 15 10

5 0

Conversion efficiency vs. charge current

(Fixed voltage mode)

98 96 94 92 90 88 86 84 82 80

VIN = 19 V

charge voltage = 12.6 V f

BATT

× I

η (%) = (V

10 m 100 m 1 10

) / (VIN × IIN) × 100

OSC

= 277.9 kHz

BATT charge current IBATT (A)

BATT voltage vs. BATT charge current

18 16 14 12 10

Dead Battery MODE

8 6 4 2 0

012345

VIN = 19 V BATT : Electronic load, (Product of KIKUSUI PLZ-150W)

DCC MODE

DCC : Dynamically Controlled Charging

BATT charge current IBATT (A)

Soft-start operating waveforms

VIN = 19 V Load : BATT = 20 Ω

−INE2 = 0 V

20 15 10

5 0

5 V

5 V 20 ms

0 80 120 160 200

t (ms)

Conversion efficiency vs. charge voltage

(Fixed current mode)

100

98 96 94 92 90 88 86 84 82

Conversion efficiency η (%)

0 2 4 6 8 10 12 14 16

VIN = 19 V BATT : Electronic load, (Product of KIKUSUI PLZ-150W)

BATT charge voltage VBATT (V)

DC/DC converter switching waveforms

VIN = 19 V

OSC

= 277.9 kHz

OUTH (V)

FB3 (V)

4 2 0

20 15 10

5 0

5 V

2 V 1 µs

0468102

Load : BATT = 1 A

t (µs)

MB3878

APPLICATION EXAMPLE 2

■■■■

System

VIN

AC Adaptor

C D

VREF

<Error

Amp.1>

VCC (O)

−

0.033 Ω

22 µF

−

0.1 µF

<OUT>

A B

OUT

+++

BATT

Drive

−

0.033 Ω

12 µH

VREF

<Error

Amp.2>

Battery

−

Bias

−

100 µF

Output voltage (Battery voltage) is adjustable

− 5 V)

<VH>

Voltage

2.5 V

1.5 V

VCC

<UVLO>

VREF

<Error

Amp.3>

35 kΩ

215 kΩ

(VCC UVLO)

−

0.91 V

(0.77 V)

4.2 V

VREF

UVLO

VCC

bias

CTL

0.1 µF

VREF

<OSC>

(45 pF)

SW OFF : Dead Battery MODE

Range of input voltage

VIN = 13V to 21V(at Load = 3A)

Note : SW ON : Differential Charging MODE

GND

5.0 V

VREF

17 6 23

0.1 µF

47 kΩ

−INE1

100 kΩ

−

× 25

+INC1

C10

5600 pF

−INC1

10 kΩ

OUTC1

R12

R14

+INE1

30 kΩ

1.3 kΩ

R13

R15

R16

FB1

30 kΩ

110 Ω

200 kΩ

−INE2

R23

−

× 25

+INC2

−INC2

OUTC2

R19

100 kΩ

VIN VIN

22 kΩ

10000 pF

R10

A(2/2)

A(1/2)

100 kΩ

+INE2

24 kΩ

−

R20

−

1 µA

VREF

<SOFT>

FB2

R11

36 kΩ

R22

100 kΩ

R21

100 kΩ

R18

−INE3

200 kΩ

R17

100 kΩ

1500 pF

OUTD

330 kΩ

FB3

2200 pF

MB3878

PARTS LIST (for APPLICATION EXAMPLE 2)

■■■■

COMPONENT ITEM SPECIFICATION VENDOR PARTS No.

Q1 Q2

D1 Diode MBRS130LT3 MOTOROLA MBRS130LT3

A Dual Op-amp MB47358 Our Company MB47358

FET FET

Si4435DY

2N7002

VISHAY SILICONIX VISHAY SILICONIX

Si4435DY

2N7002

L1 Coil 12 µH

C2, C3

C5 C6 C7 C8 C9

C10

S1, RS2

RT R3 R7 R8 R9

R10 R11

R12, R13

R14 R15 R16 R17

R18 R19, R20 R21, R22

R23

OS Condenser

OS 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 Resistor Resistor

22 µF

100 µF

2200 pF

0.1 µF

1500 pF

0.1 µF

10000 pF

0.1 µF

5600 pF

0.033 Ω 47 kΩ

330 kΩ

22 kΩ

100 kΩ

10 kΩ 36 kΩ 27 kΩ 30 kΩ

1.3 kΩ 110 Ω

200 kΩ 100 kΩ 200 kΩ 100 kΩ 100 kΩ 100 kΩ

4.0 A,

38 mΩ

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

10 %

16 V

10 %

25 V

10 %

16 V

10 %

1.0 %

0.5 %

0.5 % 5 %

1.0 %

0.5 %

1.0 %

0.5 %

1.0 %

SUMIDA CDRH124-12 µH



Note VISHAY SILICONIX : VISHAY Intertechnology, Inc.

MOTOROLA : Motorola Japan Ltd. SUMIDA : SUMIDA ELECTRIC CO., Ltd.

MB3878

USAGE PRECAUTIONS

■■■■

• Printed circuit board gr ound lines should be set up with consideration f or 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 abnormal operation

ORDERING INFORMATION

■■■■

Part number Package Remarks

MB3878PFV

24-pin plastic SSOP

(FPT-24P-M03)

■■■■ PACKAGE DIMENSION

MB3878

24-pin plastic SSOP

(FPT-24P-M03)

7.75±0.10(.305±.004)

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.

1324

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

0.25(.010)

0~8°

0.50±0.20

(.020±.008)

0.60±0.15

(.024±.006)

(Mounting height)

0.10±0.10

(.004±.004)

(Stand off)

2001 FUJITSU LIMITED F24018S-c-3-4

Dimensions in mm (inches)

MB3878

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.

F0209

FUJITSU LIMITED Printed in Japan



Fujitsu MB3878 User Manual

Specifications and Main Features

Frequently Asked Questions

User Manual

DESCRIPTION

FEATURES

PACKAGE

PIN ASSIGNMENT

PIN DESCRIPTION

BLOCK DIAGRAM

ABSOLUTE MAXIMUM RAGINGS

RECOMMENDED OPERATING CONDITIONS

ELECTRICAL CHARACTERISTICS

TYPICAL CHARACTERISTICS

FUNCTIONAL DESCRIPTION

1. DC/DC Converter Unit

2. Protection Functions

3. Soft-start Function

SETTING THE CHARGING VOLTAGE

METHOD OF SETTING THE CHARGING CURRENT

METHOD OF SETTING THE SOFT-START TIME

METHOD OF SETTING THE TRIANGULAR WAVE OSCILLATOR FREQUENCY

AC ADAPTOR VOLTAGE DETECTION

OPERATION TIMING DIAGRAM

PROCESSING WITHOUT USE OF THE CS PIN

NOTE ON AN EXTERNAL REVERSE-CURRENT PREVENTIVE DIODE

APPLICATION EXAMPLE 1

PARTS LIST (for APPLICATION EXAMPLE 1)

REFERENCE DATA

APPLICATION EXAMPLE 2

PARTS LIST (for APPLICATION EXAMPLE 2)

USAGE PRECAUTIONS

ORDERING INFORMATION

■■■■ PACKAGE DIMENSION