BD8628EFV_技术文档

TECHNICAL NOTE

System Power Supply for TV Series

Built-in 1ch FET

Synchronous Rectification Type

DC/DC converters

BD8628EFV, BD8624EFV

●Description

BD8628EFV / BD8624EFV have realized the high performance and reliability required as a power supply for thin-screen TV.

With built-in FET 1ch current mode control, the DC/DC Converter series has the advantage of high-speed load response and wide

phase margin.

Due to the high-speed load response, it is most suitable for TV-purpose processors with increasingly high performance, and due to the

wide phase margin it leaves a good margin for board pattern & constant setting and so facilitates its application design.

As a high-reliability design, it has various built-in protection circuits (overcurrent protection, output voltage abnormal protection, thermal

protection, and off-latch function at the time of abnormality etc.), therefore as an advantage it does not easily damage in every possible

abnormal condition such as all-pin short circuit test etc. and hence most suitable for thin-screen TV which requires the high reliability.

●Features

1) 1ch synchronous rectification step-down system DC/DC converter

2) Soft start, soft off function

3) Built-in low voltage / overvoltage protection function

4) Built-in overcurrent protection function

5) Frequency setting by external resistance is available. (RT terminal)

6) Protection time setting by external resistance is available. (RSET terminal)

7) Built-in RT / RSET terminal open/short protection function

8) Protection control with built-in sequencer

9) Built-in adjustment function time of off latch

10) Built-in error state detection signal output function

11) Built-in tracking function

12) Corresponded to protecting bus

13) Load current Maximum 3A

14) HTSSOP－B24 Package

Aug. 2008

● Electric characteristic

(Ta=25℃, VCC=6.5V, GND=0V,CTL=6.5V unless otherwise specified.)

specification value

Parameter

Symbol

UNIT

μA CTL=0V

Condition

MIN

-

TYP

0

3.4

MAX

10

-

Circuit current 1

Circuit current 2

I_Q1

I_Q2

mA CTL=VCC

< Error amplifier part >

Standard voltage （VREF）

Terminal FB Input bias current

Terminal FC Clamping voltage H

Terminal FC Clamping voltage L

Terminal FC Sink current

Terminal FC Source current

Open loop gain

V_REF

I_FBB

V_FCH

0.792

0.8

0

-

0.808

1

-

0.2

-

-70

-

V

Terminal FB and FC terminal short

-1

1.8

-

0.5

-

μA V_FB=0.9V

V

mA V_FB=0.9V, V_FC=0.4V

μA V_FB=0.7V, V_FC=1.6V

dB

V_FB=0.7V

V_FB=0.9V

V_FCL

I_FCSINK

I_FCSOURCE

A_VERR

-

100

When terminal RT 27kΩ is

connected

Oscillation frequency

F_OSC

400

500

600

kHz

Charging current

I_SS

-3

0.98

2.2

0.1

49

-2.5

1.08

2.4

0.15

70

-2

1.18

-

91

1.2

μA V_SS=1.0V

Terminal SS Threshold voltage

Terminal SS Clamping voltage

Terminal SS Standby voltage

Terminal SS Discharge resistance

Terminal SS Protection circuit start voltage

Maximum hysteresis error

V_SSTH

V_SSCLM

V_SSSTB

R_SS

V

V_{SS Voltage}

V

kΩ

V

V_{SS Voltage}(L→H)

CTL=0V

V_{SS Voltage}(L→H)

V_SSPON

1.0

1.1

V_{SSPON_HYS}

10

100

200

mV V_{SS Voltage}

< Low voltage, over voltage detection part＞

Terminal FB Low voltage detection voltage

Terminal FB Overvoltage detection voltage

V_LVP

V_OVP

0.51

0.86

0.56

0.96

0.61

1.06

V

V_{FB Voltage}

< Over current detection part＞

Output current limitation threshold

I_lmt

VCC-0.9 VCC-0.7 VCC-0.5

V

V_{SW Voltage}

Upper side MOS ON resistance

Lower side MOS ON resistance

<Others＞

R_ONU

R_ONL

-

110

-

mΩ

V_BOOT－V_SW=5V

mΩ V_VREG5=5V

Terminal PDET L output voltage

V_{OL_PDET}

V_{IH_CTL}

V_{IL_CTL}

I_{I_CTL}

-

2.0

-

0.4

VCC

0.5

V

I_OL=100uA

CTL terminal

Terminal CTL input voltage H level voltage

Terminal CTL input voltage L level voltage

Terminal CTL input current

-

60

90

μA CTL terminal, CTL=VCC

V_FB: FB terminal voltage, V_FC: FC terminal voltage, V_SS: SS terminal voltage, V_MONVCC: MONVCC terminal voltage

Not designed for radiation resistance.

Current capability should not exceed Pd.

2 / 14

Permissible loss

This package is a product of which the feature is the high heat radiation, and connect the back to GND

based on recommended land pattern when you mount.

T_{j max}

T^cmax

Destruction Destruction

temperature temperature

T_STGmin

T_STGmax

T_{a min}

T_{a max}

jc

/W]

ja

θ

/W]

℃

θ

℃

[

]

[

]

[

]

[

]

℃

[

]

℃

[

]

℃

19.0

31.3

-50.0

150.0

-45.0

85.0

150.0

ROHM standard substrate specification

Material 4 layer glass epoxy substrate(back copper foil70mm×70mm)

Size 70mm×70mm×1.6mmt(Sarmalbiaing is in the substrate.)

Figure 1 Heat decrease curve

※These values are the actual measurement values, and no guarantee values.

3 / 14

● Block diagram

VREF

RT

SS

FB

OSC

OPEN/SHORT

OSC

RSET

e

t i m

OVP

LVP

PDET

PIO

FC

PROTECT

BUS

I/F

SEQ

Control

GND

VREG5

CTL

VCC

CTL

VREG5

BOOT

SW

Driver

Control

PVCC

TEST2

TEST1

N.C.

SW

N.C.

PGND

N.C.

Figure-2 Block diagram・Application diagram

● Terminal explanation

No.

Symbol

Description

No.

Symbol

Description

1

2

PGND

Power GND terminal

13

14

RT

Frequency adjustment resistance connection terminal

Off latch effective time adjustment resistance terminal

RSET

No wire connection.

(Connect to GND. )

No wire connection.

(Connect to GND. )

3

4

N.C.

N.C

15

16

ＰＤＥＴ

Error state notification terminal

Error state notification

PＩＯ

and external IC error detection terminal

5

6

SW

SW terminal

17

18

CTL

Enable input

VCC

VCC power supply terminal

High side Power MOS gate drive

power source terminal

7

BOOT

19

PVCC

Power VCC terminal

8

9

VREG5

GND

FC

Internal power supply (5.0V) output terminal

20

21

22

PVCC

TEST2

TEST1

Power VCC terminal

GND

Test terminal (Connect to GND. )

10

Phase amends terminal

No wire connection.

(Connect to GND. )

No wire connection.

(Connect to GND. )

11

12

FB

SS

Feedback terminal

23

24

N.C.

Soft start adjustment capacity connection terminal

※Please give to VCC+0.3V as an operation condition in all input terminals except the terminal BOOT.

However, please do not exceed the absolute maximum rating as VCC=PVCC.

Table 1 Terminal explanation

4 / 14

● Terminal equivalent circuit chart

Terminal

Explanation

Terminal equivalent circuit chart

No.

name

Power GND

1

2

PGND

(The same potential as the GND

terminal)

Power GND

(The same potential as the GND

terminal)

PVCC

5

6

SW

SW terminal

⑤

⑥

PGND

VREG5

High side Power MOS gate drive power source

terminal

7

BOOT

⑦

PGND

8

9

VREG5

Internal power supply (5.0V) output terminal

GND

10

FC

Phase amends terminal

5 / 14

Terminal

No.

Terminal

name

Explanation

Terminal equivalent circuit chart

VCC

11

FB

Voltage detection terminal

⑪

GND

Soft start adjustment capacity connection

terminal

12

SS

Frequency adjustment resistance connection

terminal

13

14

RT

Off latch effective time adjustment resistance

terminal

RSET

15

PDET

Error state notification terminal

6 / 14

Terminal

No.

Terminal

name

Explanation

Terminal equivalent circuit chart

Error state notification and external IC error

detection terminal

16

PIO

17

21

22

CTL

Enable input

TEST2

TEST1

Test terminal (Connect to GND. )

19

20

PVCC

Power VCC terminal

7 / 14

● Operation description

ON/OFF control

DC/DC converter ON/OFF function

DC/DC converter controller can be controlled ON/OFF by CTL terminal.

Analog circuit starts operation at ON control (on mode), and goes down to setting output voltage.

Analog circuit should be standby at OFF control (off mode), and output voltage becomes 0V.

Table1 DC/DC converter ON/OFF function

CTL terminal voltage

>VIHCTL

<VILCTL

ON control

OFF control

Soft start time set function

DC/DC converter can do soft start without overshoot by charging soft start capacity (Css) connected between SS

terminal and GND by charging current at ON control.

The mute of the output is released when it reaches V_SS=0.15V (V_SSSTB), and the output voltage does the soft start

operation from the point of V_SS=0.3V (typ) in proportion to the voltage of the terminal SS.

Also, soft start time (tss) can be set by setting soft start capacity arbitrarily.

Soft start time (tss) should be set at 3msec < tss < 30msec.

※Please note that the overshoot is not caused in the output setting voltage when setting it to tss≦3msec.

V

C

SS

SSTH

t



SS

I

SS

Discharge function

DC/DC converter can do soft off by discharging load discharged to soft start capacity connected between SS terminal

to GND by discharging resistance at OFF control.

Soft off operates in proportion to the voltage of the terminal SS the output voltage from the point of VSS=0.8V (typ).

Figure 2 Wave form at ON/OFF control

8 / 14

OSC oscillation frequency setting function

SW output oscillation frequency of DC/DC converter can be set by installing resistance between RT terminal and GND

externally.

10000

1000

100

10

1

10

100

1000

RT terminal resistance[KΩ]

*Reference date

Figure 3 Terminal RT resistance-oscillation frequency

Range of terminal RT connection resistance setting

23kΩ≦Rrt≦135kΩ

（100kHz≦fosc≦600kHz）

9 / 14

PROTECT BUS Input/output function

The terminal PIO is PROTECT BUS Input/output terminal. The terminal PIO is Hi-Z when DC/DC usually operates. When the

terminal PIO becomes LOW by connecting PROTECT BUS, DC/DC is turned off. Afterwards, when the terminal PIO becomes

HIGH, it reactivates.

DC/DC is Off latch when DC/DC error detects it and the terminal PDET becomes LOW.

Table2 PIO terminal, PDET terminal output function

DC/DC

PIO terminal

PDET terminal

DC/DC

Error detection

Undetection

Detection

Hi-Z

LOW

Hi-Z

LOW

ON

OFF

Off latch

PROTECT BUS Timing chart

If two or more BD8628EFV/BD8633EFV/BD8624FV/BD8630FV is connected in PROTECT BUS, and it uses at the same time,

when one IC error detects, all remaining IC becomes PIO = Low at the same time, and the output is turned off.

Protecting BUS part timing chart

IC_A detects error.

OFF LATCH

IC_A

High

PDET

PIO

LOW

High

IC_A

PIO

IC_A

PIO

High

IC_B

PIO

LOW

IC_B

Vo

DC/DC OFF

0V

High

IC_B

PDET

When two or more BD8628EFV/BD8633EFV/BD8624FV/BD8630FV is used at the same time,

If one IC error detects, all IC becomes DC/DC OFF at the same time.

10 / 14

● Protection function

Protection circuit is effective for destruction prevention due to accident so that avoid using by continuous protection

operation.

Low voltage protection function(LVP)

Low voltage protection function detects set output voltage VO from FB terminal and off-latched DC/DC converter

compared to internal reference level.

Low voltage protection function operates when FB terminal voltage falls below VLVP (=0.7 × VREF) and continues more

than set time in external resistance.

Table 4 Low voltage protection function

CTL

terminal

Low voltage

protection function

Low voltage

protection operation

SS terminal

>1.1V(typ)

FB terminal

<VLVP

ON

Enable

>VIHCTL

>VLVP+VLVP_HYS

OFF

<1.0V(typ)

-

Disable

<VILCTL

※Constant voltage protection function is enabled when SS terminal voltage becomes more than 1.1V (typ) in the transition

to ON control (during soft start).

Overvoltage protection function (OVP)

Overvoltage protection function detects set output voltage VO from FB terminal and off-latched DC/DC converter

controller compared to internal reference level.

Overvoltage protection function operates when FB terminal voltage exceeds VOVP (=1.2 × VREF) and continues more

than set time in external resistance.

Table 5 Overvoltage protection function

CTL

terminal

Overvoltage

protection function

Overvoltage

protection operation

ON

SS terminal

FB terminal

>VOVP

>1.1V(typ)

Enable

>VIHCTL

<VOVP

OFF

<1.0V(typ)

-

Disable

<VILCTL

※Overvoltage protection function is enabled when SS terminal voltage of each Ch becomes more than 1.1V (typ) in the

transition to ON control (during soft start).

Figure 5-1．Low voltage / overvoltage protection

11 / 14

Overcurrent protection function (OCP)

Overcurrent protection function compared drain voltage (LX terminal voltage) with internal OCP terminal voltage when

internal Nch POWER MOS is ON. When LX terminal voltage becomes lower than OCP terminal voltage, external MOS

would be OFF.

Off latch by overcurrent protection function operates when LX terminal voltage falls below OCP terminal voltage and

continues more than set time in external resistance.

Table 6 overcurrent protection function

CTL

terminal

>VIHCTL

Overcurrent

protection function

Overcurrent

protection operation

ON

SS terminal

Output current

>1.1V(typ)

>Ilmt

<Ilmt

-

Enable

OFF

<1.0V(typ)

-

Disable

<VILCTL

-

DRV

A

DRV

B

Output

current

Rocp

LX

OCP

Figure 5-2．Overcurrent protection

RT terminal open/short protection function

RT terminal open/shot protection function off-latches all DC/DC converter controller by detecting open/short

condition internally from RT terminal to prevent from output voltage error caused by error oscillation of

internal triangular wave at RT terminal open/short.

RT terminal open/short protection function is regularly enabled after boot-up.

RT terminal open/short protection function operates when error detection condition continues more than set

time in external resistance.

12 / 14

Soft start time-out function

DC/DC converter off-latch-controls when V_SSdoes not exceed V_SSPONfrom V_SS> V_SSSTB+V_{SSSTB_HYS}after 50msec (typ)

passed from soft start.

Figure 5-3. At soft start time-out

Error detection (off latch) release method

DC/DC converter becomes off latch condition when protection function operates. Off latch can be released by the

following method. DC/DC converter controller of each Ch becomes able to do ON control transition by releasing off latch.

1. Set all Ch CTL terminal voltage as < V_ILCTLand continue that condition about more than 200usec (typ).

2. Drop down power supply VCC to below 2.7V(TYP).

Error detection time set function

Time from the error detection to the off latch can be set by putting resistance outside between GND and RSET terminal.

3

t

 1.810 Rrset[usec]

offlatch

Rset setting range

10kΩ≦Rset≦75kΩ

（18usec≦tofflach≦135usec）

13 / 14

HTSSOP-B24

Tape

Embossed carrier tape

Quantity

2000pcs

7.8 0.1

+6

−4

4

Direction

of feed

E2

24

13

(The direction is the 1pin of product is at the upper left when you hold

reel on the left hand and you pull out the tape on the right hand)

+0.05

−0.03

1

12

0.17

0.08

0.325

S

0.65

+0.05

−0.04

0.2

M

0.08

Direction of feed

1pin

Reel

（Unit:mm)

※When you order , please order in times the amount of package quantity.

14 / 14

Appendix

Notes

No technical content pages of this document may be reproduced in any form or transmitted by any

means without prior permission of ROHM CO.,LTD.

The contents described herein are subject to change without notice. The specifications for the

product described in this document are for reference only. Upon actual use, therefore, please request

that specifications to be separately delivered.

Application circuit diagrams and circuit constants contained herein are shown as examples of standard

use and operation. Please pay careful attention to the peripheral conditions when designing circuits

and deciding upon circuit constants in the set.

Any data, including, but not limited to application circuit diagrams information, described herein

are intended only as illustrations of such devices and not as the specifications for such devices. ROHM

CO.,LTD. disclaims any warranty that any use of such devices shall be free from infringement of any

third party's intellectual property rights or other proprietary rights, and further, assumes no liability of

whatsoever nature in the event of any such infringement, or arising from or connected with or related

to the use of such devices.

Upon the sale of any such devices, other than for buyer's right to use such devices itself, resell or

otherwise dispose of the same, no express or implied right or license to practice or commercially

exploit any intellectual property rights or other proprietary rights owned or controlled by

ROHM CO., LTD. is granted to any such buyer.

Products listed in this document are no antiradiation design.

The products listed in this document are designed to be used with ordinary electronic equipment or devices

(such as audio visual equipment, office-automation equipment, communications devices, electrical

appliances and electronic toys).

Should you intend to use these products with equipment or devices which require an extremely high level

of reliability and the malfunction of which would directly endanger human life (such as medical

instruments, transportation equipment, aerospace machinery, nuclear-reactor controllers, fuel controllers

and other safety devices), please be sure to consult with our sales representative in advance.

It is our top priority to supply products with the utmost quality and reliability. However, there is always a chance

of failure due to unexpected factors. Therefore, please take into account the derating characteristics and allow

for sufficient safety features, such as extra margin, anti-flammability, and fail-safe measures when designing in

order to prevent possible accidents that may result in bodily harm or fire caused by component failure. ROHM

cannot be held responsible for any damages arising from the use of the products under conditions out of the

range of the specifications or due to non-compliance with the NOTES specified in this catalog.

Thank you for your accessing to ROHM product informations.

More detail product informations and catalogs are available, please contact your nearest sales office.

THE AMERICAS / EUROPE / ASIA / JAPAN

ROHM Customer Support System

Contact us : webmaster@ rohm.co.jp

www.rohm.com

TEL : +81-75-311-2121

FAX : +81-75-315-0172

21 Saiin Mizosaki-cho, Ukyo-ku, Kyoto 615-8585, Japan

Appendix1-Rev2.0


型号：	BD8628EFV
厂家：	ROHM
描述：	Built-in 1ch FET Synchronous Rectification Type DC/DC converters 内置1通道FET同步整流型DC / DC转换器转换器
文件：	总15页 (文件大小：634K)
中文：	中文翻译
下载：	下载PDF数据表文档文件

BD8628EFV [ROHM]

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