Fujitsu MB39A104 User Manual

FUJITSU SEMICONDUCTOR

DATA SHEET

DS04-27231-3E

ASSP For Power Management Applications (General Purpose DC/DC Converter)

2-ch DC/DC Converter IC

with Overcurrent Protection

MB39A104

DESCRIPTION

■

The MB39A104 is a 2-channel DC/DC converter IC using pulse width modulation (PWM), incorporating an overcurrent protection circuit (requiring no current sense resistor). This IC is ideal for down conversion.

Operating at high frequency reduces the value of coil. This is ideal for built-in power supply such as LCD monitors and ADSL. This product is covered by US Patent Number 6,147,477.

FEATURES

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• Built-in timer-latch overcurrent protection circuit (requiring no current sense resistor)

• Power supply voltage range : 7 V to 19 V

• Reference voltage : 5.0 V ± 1 %

• Error amplifier threshold voltage : 1.24 V ± 1 %

• High-frequency operation capability : 1.5 MHz (Max)

• Built-in standby function: 0 µA (Typ)

• Built-in soft-start circuit independent of loads

• Built-in totem-pole type output for Pch MOS FET

PACKAGE

■

24-pin plastic SSOP

(FPT-24P-M03)

MB39A104

PIN ASSIGNMENTS

■

(TOP VIEW)

VCCO :

VH :

OUT1 :

VS1 :

ILIM1 :

DTC1 :

VCC :

CSCP :

FB1 :

−INE1 :

CS1 :

RT :

: CTL

: GNDO

: OUT2

: VS2

: ILIM2

: DTC2

: GND

: VREF

: FB2

: −INE2

: CS2

: CT

(FPT-24P-M03)

MB39A104

PIN DESCRIPTION

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Pin No. Symbol I/O Descriptions

1VCCO Output circuit power supply terminal (Connect to same potential as VCC pin.) 2 VH O Power supply terminal for FET drive circuit (VH = V 3 OUT1 O External Pch MOS FET gate drive terminal 4 VS1 I Overcurrent protection circuit input terminal

Overcurrent protection circuit detection resistor connection terminal. Set

5ILIM1I

6DTC1I

7VCC 8CSCP Timer-latch short-circuit protection capacitor connection terminal

9 FB1 O Error amplifier (Error Amp 1) output terminal 10 −INE1 I Error amplifier (Error Amp 1) inverted input terminal 11 CS1  Soft-start capacitor connection terminal 12 RT  Triangular wave oscillation frequency setting resistor connection terminal 13 CT  Triangular wave oscillation frequency setting capacitor connection terminal 14 CS2  Soft-start capacitor connection terminal 15 −INE2 I Error amplifier (Error Amp 2) inverted input terminal 16 FB2 O Error amplifier (Error Amp 2) output terminal

overcurrent detection reference voltage depending on external resistor and internal current resource (110 µA at RT = 24 kΩ)

PWM comparator block (PWM) input terminal. Compares the lowest voltage among FB1 and DTC terminals with triangular wave and controls output.

Power supply terminal for reference power supply and control circuit (Connect to same potential as the VCCO terminal)

CC − 5 V)

17 VREF O Reference voltage output terminal 18 GND 

19 DTC2 I

20 ILIM2 I

21 VS2 I Overcurrent protection circuit input terminal 22 OUT2 O External Pch MOS FET gate drive terminal 23 GNDO  Output circuit ground terminal (Connect to same potential as GND terminal.)

24 CTL I

Output circuit ground terminal (Connect to same potential as GNDO terminal.)

PWM comparator block (PWM) input terminal. Compares the lowest voltage among FB2 and DTC terminals with triangular wave and controls output.

Overcurrent protection circit detection resistor connection terminal. Set overcurrent detection reference voltage depending on external resistor and internal current resource (110 µA at RT = 24 kΩ)

Power supply control terminal. Setting the CTL terminal at “L” level places IC in the standby mode.

MB39A104

■ BLOCK DIA GRAM

−INE1

CS1

FB1

10 µA

VREF

1.24 V

Error Amp1

− +

L priority

PWM Comp.1

+ +

−

CH1

Drive1

Pch

IO = 200 mA at VCCO = 12 V

VCCO

OUT1

DTC1

−INE2

CS2

FB2

DTC2

CSCP

10 µA

16 19

H: at SCP

VREF

1.24 V

SCP

Logic

UVLO

OSC

12 13 1817

RT CT GNDVREF

− +

L priority

H priority

SCP Comp.

H:UVLO release

Error Amp2

+ +

−

(3.1 V)

L priority

2.5 V

1.5 V

Accuracy

±1%

PWM Comp.2

+ +

−

5.0 V

bias

Current

Protection

Logic

CH2

Pch

O = 200 mA

at VCCO = 12 V

Current

Protection

Logic

H: at OCP

Voltage

Error Amp Power Supply

Error Amp Reference

1.24 V

VREF

VR1

Drive2

Bias

Power

ON/OFF

− +

CC − 5 V

CTL

4 5

21 20

VS1 ILIM1

OUT2

VS2 ILIM2

GNDO

VCC

CTL

ABSOLUTE MAXIMUM RATINGS

■

MB39A104

Parameter Symbol Condition

Unit

Min Max

Rating

Power supply voltage V Output current I Output peak current I Power dissipation P Storage temperature T

CC VCC, VCCO terminal  20 V O OUT1, OUT2 terminal  60 mA

OP Duty ≤ 5% (t = 1/fOSC×Duty)  700 mA

D Ta ≤ +25 °C  740* mW

STG −55 +125 °C

* : The packages are mounted on the 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

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Parameter Symbol Condition

Power supply voltage V Reference voltage output current I VH output current I

Input voltage

V Control input voltage V Output current I Output Peak current I

Oscillation frequency f

Min Typ Max

CC VCC, VCCO terminal 7 12 19 V

REF VREF terminal −1  0mA

VH VH terminal 030 mA

INE −INE1, −INE2 terminal 0  VCC − 0.9 V DTC DTC1, DTC2 terminal 0  VCC − 0.9 V CTL CTL terminal 0  19 V

O OUT1, OUT2 terminal −45 +45 mA

Duty ≤ 5% (t = 1/fOSC×Duty)

OSC

Overcurrent detection by ON resistance of FET

−450 +450 mA 100 500 1000 kHz

Value

Unit

* 100 500 1500 kHz Timing capacitor C Timing resistor R VH terminal capacitor C Soft-start capacitor C Short-circuit detection capacitor C Reference voltage output

capacitor

T  39 100 560 pF T  11 24 130 kΩ

VH VH terminal  0.1 1.0 µF

S CS1, CS2 terminal  0.1 1.0 µF

SCP CSCP terminal  0.1 1.0 µF

REF VREF terminal  0.1 1.0 µF

Operating ambient temperature Ta −30 +25 +85 °C

* : See“ ■ SETTING THE TRIANGULAR OSCILLATION FREQUENCY”. 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.

MB39A104

ELECTRICAL CHARACTERISTICS

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Parameter

Output voltage VREF 17 Ta = +25 °C 4.95 5.00 5.05 V Output voltage

temperature variation

Input stability Line 17 VCC = 7 V to 19 V  310mV

voltage

Load stability Load 17 VREF = 0 mA to −1 mA  110mV

block [REF]

1.Reference Short-cuircuit

output current

Threshold voltage

2.Under voltage lockout

Hysteresis

block [UVLO]

width

protection circuit

Threshold voltage

Input source current

[SCP Logic]

3.Short-circuit

Reset voltage V

detection block

Symbol

REF/

∆V

REF

OS 17 VREF = 1 V −50 −25 −12 mA

TLH 17 VREF = 2.6 2.8 3.0 V

THL 17 VREF = 2.4 2.6 2.8 V

H 17 0.2 *  V

TH 8  0.68 0.73 0.78 V

CSCP 8 −1.4 −1.0 −0.6 µA

RST 17 VREF = 2.4 2.6 2.8 V

(VCC = VCCO = 12 V, VREF = 0 mA, Ta = +25 °C)

Value

Pin No Conditions

Unit

Min Typ Max

17 Ta = 0 °C to +85 °C  0.5* %

Threshold voltage

[SCP Comp]

4.Short-circuit

detection block

Oscillation frequency

[OSC]

Frequency

5.Triangular

start

6.Soft-

variation

wave oscillator

Charge current ICS 11, 14 CS1 = CS2 = 0 V −14 −10 −6 µA

block

temperature

block

[CS1, CS2]

Threshold voltage

Input bias

bolck

7.Error amplifier

current

[Error Amp1,

Error Amp2]

Voltage gain A

TH 8  2.8 3.1 3.4 V

OSC 13 CT = 100 pF, RT = 24 kΩ 450 500 550 kHz

OSC/

∆f

OSC

TH 9, 16 FB1 = FB2 = 2 V 1.227 1.240 1.253 V

B 10, 15 −INE1 = −INE2 = 0 V −120 −30  nA

V 9, 16 DC  100*  dB

13 Ta = 0 °C to +85 °C  1* %

(Continued)

(VCC = VCCO = 12 V, VREF = 0 mA, Ta = +25 °C)

Parameter Symbol Pin No. Conditions

MB39A104

Value

Unit

Min Typ Max

Frequency bandwidth

Output voltage

Output source

[Error Amp1,

Error Amp2]

current

8.Error amplifier bolck

Output sink current I

Threshold voltage

block

Input current I

PWM Comp.2]

[PWM Comp.1,

9.PWM comparator ILIM terminal input

current

block

Offset voltage V

10.Overcurrent

11.Bias

[OCP1, OCP2]

protection circuit

Output voltage VH 2

[VH]

block

voltage

Output source current

Output sink current ISINK 3, 22

[Drive1, Drive2]

12.Output block

Output ON resistor

CTL input voltage

BW 9, 16 A V

OH 9, 16  4.7 4.9  V

OL 9, 16 40 200 mV

SOURCE 9, 16 FB1 = FB2 = 2 V −2 −1mA

SINK 9, 16 FB1 = FB2 = 2 V 150 200 µA

T0 6, 19 Duty cycle = 0 % 1.4 1.5  V

T100 6, 19 Duty cycle = Dtr  2.5 2.6 V

DTC 6, 19 DTC1 = DTC2 = 0.4 V −2.0 −0.6 µA

LIM 5, 20 RT = 24 kΩ, CT = 100 pF 99 110 121 µA

IO 5, 20 1 *  mV

V = 0 dB  1.6*  MHz

VCC = VCCO = 7 V to 19 V VH = 0 mA to 30 mA

VCC−

5.5

VCC−

5.0

VCC−

4.5

OUT1 to OUT4 = 7 V,

ISOURCE 3, 22

Duty ≤ 5 % (t = 1/f

OSC×Duty)

−300  mA

OUT1 to OUT4 = 12 V, Duty ≤ 5 % (t = 1/f

OH 3, 22 OUT1 = OUT2 = −45 mA  8.0 12.0 Ω

OL 3, 22 OUT1 = OUT2 = 45 mA  6.5 9.7 Ω

IH 24 IC Active mode 2  19 V

IL 24 IC Standby mode 0  0.8 V

OSC×Duty)

 350  mA

[CTL]

Input current

13.Control block Standby current ICCS 1, 17 CTL = 0 V  010µA

Power supply current

14.General

*: Standard design value.

CTLH 24 CTL = 5 V  50 100 µA

CTLL 24 CTL = 0 V 1 µA

CC 1, 17 CTL = 5 V  4.0 6.0 mA

MB39A104

TYPICAL CHARACTERISTICS

■

Power Supply Current vs. Power Supply Voltage

Power supply current ICC (mA)

0 5 10 15 20

Power supply voltage VCC (V)

Ta = +25 °C CTL = 5 V

Reference Voltage vs. Ambient Temperature

Ta = +25 °C VCC = 12 V CTL = 5 V

Reference Voltage vs. Power Supply Voltage

REF (V)

Reference voltage V

0 5 10 15 20

Power supply voltage V

Ta = +25 °C CTL = 5 V VREF = 0 mA

CC (V)

Reference Voltage vs. Ambient Temperature

2.0

1.5

1.0

0.5

0.0

−0.5

VCC = 12 V CTL = 5 V VREF = 0 mA

Reference voltage VREF (V)

0 5 10 15 20 25 30 35

Ambient temperature Ta (°C)

CTL terminal Current vs. CTL terminal Voltage

500

400

300

200

100

CTL terminal current ICTL (µA)

0 5 10 15 20

VREF

ICTL

Ta = +25 °C VCC = 12 V VREF = 0 mA

CTL terminal voltage VCTL (V)

10 9 8 7 6 5 4 3 2 1 0

Reference voltage VREF (V)

−1.0

−1.5

Reference voltage ∆VREF (%)

−2.0

−40 −20 0 20 40 60 80 100

Ambient temperature Ta (°C)

(Continued)

MB39A104

Triangular Wave Oscillation Frequency

vs. Timing Resistor

10000

1000

OSC (kHz)

100

CT = 560 pF

frequency f

Triangular wave oscillation

1 10 100 1000

Timing resistor RT (kΩ)

CT = 220 pF

Ta = +25 °C VCC = 12 V CTL = 5 V

CT = 39 pF

CT = 100 pF

Triangular Wave Upper and Lower Limit Voltage

vs. Triangular Wave Oscillation Frequency

3.2 Ta = +25 °C

3.0

VCC = 12 V CTL = 5 V

2.8

CT (V)

lower limit voltage V

Triangular wave upper and

RT = 47 kΩ

2.6

2.4

2.2

2.0

1.8

1.6

1.4

1.2

0 200 400 600 800 1000 1200

Triangular wave oscillation frequency fOSC (kHz)

Upper

Lower

16001400

Triangular Wave Oscillation Frequency

vs. Timing Capacitor

10000

1000

OSC (kHz)

100

RT = 130 kΩ

frequency f

Triangular wave oscillattion

10 100 1000 1000

Timing capacitor CT (pF)

RT = 68 kΩ

Ta = +25 °C VCC = 12 V CTL = 5 V

RT = 11 kΩ

RT = 24 kΩ

Triangular Wave Upper and Lower Limit Voltage

vs. Ambient Temperature

3.2 VCC = 12 V

3.0

CTL = 5 V RT = 24 kΩ

2.8 CT = 100 pF

CT (V)

2.6

2.4

2.2

2.0

1.8

1.6

1.4

lower limit voltage V

Triangular wave upper and

1.2

−40 −20 0 20 40 60 80 100

Ambient temperature Ta ( °C)

Upper

Lower

Triangular Wave Oscillation Frequency

vs. Ambient Temperature

560

540

520

OSC (kHz)

500

480

frequency f

460

Triangular wave oscillation

440

−40 −20 0 20 40 60 80 100

Ambient temperature Ta ( °C)

VCC = 12 V CTL = 5 V RT = 24 kΩ CT = 100 pF

Triangular Wave Oscillation Frequency

vs. Power supply voltage

560

540

520

OSC (kHz)

500

480

frequency f

460

Triangular wave oscillation

440

0 5 10 15 20

Power supply voltage VCC (V)

Ta = +25 °C CTL = 5 V RT = 24 kΩ CT = 100 pF

(Continued)

MB39A104

(Continued)

Error Amplifier, Gain, Phase vs. Frequency

Ta = +25 °C VCC = 12 V

Gain AV (dB)

40 30 20 10

−10

−20

−30

−40

100 1 k 10 k 100 k 1 M 10 M

Frequency f (Hz)

Power Dissipation vs. Ambient Temperature

1000

800 740

180

−90

−180

Phase φ (deg)

10 kΩ

1 µF

10 kΩ

2.4 kΩ

(15)

10 11

(14)

240 kΩ

− +

1.24 V

(16)

Error Amp1

(Error Amp2)

OUT

600

400

200

Power dissipation PD (mW)

−40 −20 0 20 40 60 80 100

Ambient temperature Ta ( °C)

MB39A104

FUNCTIONS

■

1. DC/DC Converter Functions

(1) Reference voltage block (REF)

The reference voltage circuit generates a temperature-compensated reference voltage (5.0 V Typ) from the voltage supplied from the power supply terminal (pin 7). The voltage is used as the reference voltage for the IC’s internal circuitry. The reference voltage can supply a load current of up to 1 mA to an external device through the VREF terminal (pin 17).

(2) Triangular-wave oscillator block (OSC)

The triangular wave oscillator incorporates a timing capacitor and a timing resistor connected respectively to the CT terminal (pin 13) and RT terminal (pin 12) to generate triangular oscillation wavef orm amplitude of 1.5 V to 2.5 V. The triangular waveforms are input to the PWM comparator in the IC.

(3) Error amplifier block (Error Amp1, Error Amp2)

The error amplifier detects the DC/DC converter output voltage and outputs PWM control signals. In addition, an arbitrary loop gain can be set by connecting a feedback resistor and capacitor from the output terminal to inverted input terminal of the error amplifier, enabling stable phase compensation to the system. Also, it is possib le to prevent rush current at power supply start-up by connecting a soft-start capacitor with the CS1 terminal (pin 11) and CS2 terminal (pin 14) which are the non-inverted input ter minal for Error Amp. The use of Error Amp for soft-start detection makes it possible for a system to oper ate on a fixed soft-start time that is independent of the output load on the DC/DC converter.

(4) PWM comparator block (PWM Comp.)

The PWM comparator is a voltage-to-pulse width modulator that controls the output duty depending on the input/ output voltage. The comparator keeps output transistor on while the error amplifier output voltage remain higher than the triangular wave voltage.

(5) Output block

The output block is in the totem pole configuration, capable of driving an external P-channel MOS FET.

(6) Bias voltage block (VH)

This bias voltage circuit outputs V circuit outputs the potential equal to V

CC − 5 V(Typ) as minimum potential of the output circuit. In standby mode , this

CC.

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