BD9207FPS [ROHM]

Step-down type with 1.5A output; 用1.5A输出降压型


型号：	BD9207FPS
厂家：	ROHM
描述：	Step-down type with 1.5A output 用1.5A输出降压型
文件：	总12页 (文件大小：344K)
中文：	中文翻译
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LED Driver series for lighting

Step-down type

with 1.5A output

BD9207FPS

No.09093EAT01

●Description

BD9207FPS is a LED driver with built-in step-down switching regulator and incorporates the built-in switching MOS EFT of

Pch.

Feedback voltage is as low as 0.2V and can suppress the loss on the sense resistance of LED.

It is operated by PWM method with an oscillating frequency of 900 KHz and can use smaller coil than a switching regulator

of low-frequency operation.

●Features

1) Maximum switching current of 1.5A

2) Built-in Pch switching MOS FET for high efficiency

3) Low loss because feedback voltage is as low as 0.2V

4) High oscillating frequency of 900KHz (Fixed)

5) Built-in soft start function

6) Built-in overcurrent protection circuit (OCP)

7) Built-in thermal shutdown circuit (TSD)

8) ON/OFF of output is possible by STBY terminal.

9) Compact surface-mount TO252S-5 package

●Applications

・For use in the light sources of PPC

・Printer etc. and the LCD backlights of LED lighting apparatus & monitor

・Note PC etc.

●Absolute maximum ratings（Ta=25℃）

Parameter

Supply voltage（VCC-GND）

STBY-GND Voltage

Symbol

Vcc

Rating

Unit

V_STBY

V_OUT

V_INV

OUT-GND Voltage

INV-GND Voltage

Maximum switching output current.

Allowable loss

Iout

1.5(*1)

800(*2)

-20 ~ +85

-55 ~ +150

℃

Operating temperature range

Storage temperature range

Topr

Tstg

(*1)Regardless of the listed rating, do not exceeded Pd, ASO or Tjmax=150℃.

(*2) Without heat sink, reducing by the 16 mW every 1℃ rise in temperature. (above 25℃)

www.rohm.com

2009.07 - Rev.A

1/11

Technical Note

BD9207FPS

●Operating range (Ta=-40～+85℃)

Limit

Parameter

Symbol

Unit

Conditions

Min.

8.0

Typ.

Max.

35.0

0.8×

(VCC-Io×Ron)

Supply voltage

Output voltage

VCC

2.5

●Electrical characteristics（Unless otherwise specified, Ta=25℃,VCC=24V,STBY=3V）

Limit

Typ.

Parameter

Symbol

Unit

Conditions

Min.

Max.

1.5

Output MOS ON resistance

Oscillating frequency

Ron

fosc

1.0

Ω

kHz

810

1.6

900

990

Overcurrent detection current

Iocp

VINV

IINV

0.200

0.206

INV terminal threshold

voltage

0.194

VINV=0.2V

INV terminal bypass current

μA

OFF

VSTBYON

VSTBYOFF

2.0

-0.3

0.3

STBY terminal control

voltage

STBY=3V

STBY terminal inflow current

Circuit current

Istby

Icc

μA

STBY＝0V

Standby current

Ist

STBY＝0→3V

Soft start time

Tss

Without radiation-proof design.

www.rohm.com

2009.07 - Rev.A

2/11

Technical Note

BD9207FPS

●Block diagram

VCC

VREF

PWM COMP

DRIVER

OSC

STBY

CTL

LOGIC

OUT

INV

OCP

TSD

Error AMP

FIN

GND

●Outline drawing of package

●Explanation of terminal

Pin No.

Pin Name

VCC

Function

Supply voltage

terminal

Drain terminal of

built-in PMOS FET

OUT

Drain terminal of

built-in PMOS FET

3※

FIN

GND

INV

Ground terminal

Output voltage

feedback

terminal

ON/OFF control

terminal

STBY

※Used normally in open-circuit condition

TO252S-5（Unit：mm）

www.rohm.com

2009.07 - Rev.A

3/11

Technical Note

BD9207FPS

●Functional explanation of block

・

VREF

The constant voltage to be temperature-compensated is created from the voltage inputted from VCC terminal.

OSC

Triangular wave with an oscillating frequency of 900 KHz is created, as an input of PWM comparator, by built-in resistor

and capacitor.

・

Error AMP

It detects, at INC terminal, the voltage of sense resistance terminal created by LEC current, and compares it to the

reference voltage, and amplifies and outputs the differential voltage.

(The reference voltage is 0.2V±3%)

PWM COMP

PWM COMP converts the output voltage of error amplifier into the pulse-width modulation waveform and outputs it to

DRIVER.

・

DRIVER

Push-pull FET driver takes in the PWM waveform and directly drives the Pch MOS FET that is built-in in the IC.

STBY

The ON/OFF control of output is performed by STBY terminal. The output becomes ON if STBY voltage is High level.

・

Thermal shutdown circuit (TSD)

TSD circuit protects the IC from runaway thermal operation or heat damage.

TSD circuit detects the temperature of chip, and the circuit becomes off if the temperature reaches 175℃. For TSD

detection and release, the hysteresis of 15℃ is set, so the malfunction caused by temperature variation is prevented.

・

Over Current Protection（OCP）

Out is turned off if the voltage difference between VCC – OUT, caused by the current flowing in the Pch MOS EFT built-in

in OCP circuit, is detected and reaches the reference value of OCP. The OCP is not of latch type but of self-return type.

Soft start circuit (SS)

Soft start time is set by the built-in capacitor connected to SS circuit. The capacitor is charged when STBY terminal

becomes High level and the IC is started. The soft start time is set at 4ms or so.

www.rohm.com

2009.07 - Rev.A

4/11

Technical Note

BD9207FPS

●Selection and setting of application parts

Coil L1

The application efficiency will decrease by the larger serial resistance element of coil. Moreover, because OCP operates

by 1.6A(min) or more, so please notice the heat generated by overload output or short.

Please set current ratings of coil with I_OUT(MAX)＋⊿IL or more. Iout（MAX）: maximum load current

If current flows more than ratings current, then coil generates heat, magnetic saturation, and causes oscillation or low

efficiency.

Please select the peak current with enough margins not to exceed current rating of coil.

fosc

(VCC－VOUT)

VOUT

VCC

⊿IL_.=

L1: Coil value,VCC: Input voltage,VOUT: Output voltage, ⊿IL: Ripple current, fosc: Oscillation frequency

When value the efficiency , we recommend C10-H5R(mitsumi) . Efficiency will be improved about 1~2%.

Schottky diode D1

Please select Schottky diode with lowest forward voltage VF.

(We can suppress the dissipation of forward voltage descent, and raise the efficiency. ）

Diode selection is based on maximum forward current rating, reverse voltage rating and permissible power dissipation of

diode.

・The maximum current ratings are assumed more than the value of maximum load current+ coil ripple current（⊿I_L）.

・Reverse voltage rating is set to be VIN or more.

・Please choose the smallest one of reverse current IR.

Especially, IR grows at high temperature, and causes thermo runaway.

・Select the diode which permissible power dissipation within ratings.

Diode power dissipation Pdi is shown below.

Pdi=Iout(MAX)×Vf×(1-VOUT/VCC)

Iout（MAX）: Load current. Vf: Forward voltage, VOUT: Output voltage, VCC: Input voltage

Output capacitor C1

Select the output capacitor with ESR met the following formula.

ESR≦⊿VL/⊿IL

⊿VL : Permissible ripple voltage, ⊿IL : Ripple current

Moreover, permissible ripple current effective value of output capacity is calculated by the next formula, and use this

value to select the capacitor with enough margins.

IRMS =⊿IL/2√3

IRMS: Permissible ripple current effective value of output capacity, ⊿IL : Ripple current

Ceramic capacitor must use the one more than B characteristic.

Besides above mentioned, IC might not be normally operated according to the different setting condition of ambient

temperature and output voltage.

Moreover, even aluminum electrolytic capacitor can be used, please confirm its operation enough before using it.

Input capacitor C2

Input capacitor built in Pch MOS FET ON is the current supply of coil by FET.

So, please close to IC as near as possible to connect it. Enough margins is taken on setting input capacitor in capacitor

withstand voltage and permissible ripple current value. According to the ripple current effective value of input capacitor

shown below, select the capacitor with enough permissible ripple current value.

IRMS＝IOUT×√

(1－VOUT / VCC)×VOUT / VCC

IRMS : Permissible ripple current value of input capacitor

IOUT : Load current. VOUT: Output voltage, VCC: Input voltage

www.rohm.com

2009.07 - Rev.A

5/11

Technical Note

BD9207FPS

Resistance R1

LED Current value is set below according to sense resistance R1.

ILED[A]＝VINV[V]/R1[Ω]

＝0.2V/R1[Ω]

Moreover, DCDC Output voltage will be the value below.

VO[V]＝VF（LED Forward voltage）＋VINV[V]

＝VF＋0.2V(typ)

● Recommended circuit example and notes of substrate layout

・

To prevent noise and low efficiency, please set up the capacitor and Schottky diode between VCC – GND as near as

possible to IC.

Please connect the resistance and output LC filter capacitor between INV – GND with same GND for the stability of

output voltage.

Coil

L1＝10μH

：C6-K3LA（mitsumi）

Diode

Capacitor

：RB050LA-30（ROHM）

：Ceramic capacitor GRM31CB31E106KA75L(murata)

C1＝10μF(25V)

C2＝4.7μF(50V)

R1＝0.43Ω

：Ceramic capacitor

GRM32EB31H475KA87L(murata)

Resistance

：MCR10EZPFR430（ROHM）

www.rohm.com

2009.07 - Rev.A

6/11

Technical Note

BD9207FPS

● Measurement circuit diagram

GND

FIN

OUT

STBY

Vcc

INV

cccc

SW2

SW4

SW5

Icc

Vcc

ISTB

VSTB

IINV

0.43Ω

V^INV

SW6

www.rohm.com

2009.07 - Rev.A

7/11

Technical Note

BD9207FPS

● Heat transfer characteristic

①IC unit

②2 layers substrate(area of substrate back copper foil:15 mm×15mm)

③2 layers substrate(area of substrate back copper foil:70 mm×70mm)

（W）

③3.50W

②1.85W

①0.80W

75 85

100

125

150

（℃）

AMBIENT TEMPERATURE [Ta]

● I/O terminal equivalent circuit diagram

1Pin,FIN (VCC, GND)

2pin (OUT)

4pin (INV)

5pin (STBY)

VCC

STBY

VCC

INV

OUT

GND

www.rohm.com

2009.07 - Rev.A

8/11

Technical Note

BD9207FPS

●Notes for use

1. We have paid enough attention to quality control of this product, but it may be destroyed when the absolute

maximum rating of impressed voltage and operating temperature range is exceeded. Because we can’t specify

that is short-mode or open-mode etc while it is destroyed, so please discuss to give physical safety action with

postulating the special mode exceeded absolute maximum rating.

2. About application circuit

Application circuit is recommended, but please fully confirm temperature characteristic etc when using it. Moreover,

please acknowledge that our company can’t confirm enough about patent.

3. About the range of operation power-supply voltage

Circuit function operation at the range of operation ambient temperature is guaranteed when it is in the range of

operation power-supply voltage. About characteristic value, the specification value of electric characteristic can’t

be guaranteed, but the characteristic value doesn’t change rapidly in these ranges.

4. About ground connection

The ground connection shown in application circuit example should equip enough fat GND（FIN） to every ground

connection with shortest pattern drawing, and the pattern shouldn’t interfere the electric characteristic.

5. About input power-supply

The input power-supply shown in application circuit example should equip input pin VCC(1pin) with short enough

pattern drawing, and the pattern shouldn’t interfere the electric characteristic.

6. Please think about permissible power dissipation (Pd) in an actual using status, and do the heat design with

enough margins.

7. Please pay enough attention to the direction and displacement of IC when you install it on PCB. If you install it by

mistake, IC might be destroyed, Moreover, when short-circuit happen by foreign substance entered between

outputs, or output and power supply GND, it will be destroyed.

8. Please note that there is a possibility of malfunction if you use it in strong electromagnetic field.

9. Please set STBY terminal voltage to 0.3V or less when putting it on standby status, to 2.0V or more when putting it

on operation status.

Please do not fix STBY terminal voltage from 0.3V to 2.0V. It may cause malfunction or breakdown.

www.rohm.com

2009.07 - Rev.A

9/11

Technical Note

BD9207FPS

10. This IC is a monolithic IC, and there are P + isolation and P substrate for element separation between each

element. P-N joint is formed with this P layer and N each element’s layer, and various parasitic elements are

composed.

For instance, as shown in the figure below, when resistance and transistor are connected with terminal:

○

P-N joint operates as a parasitic diode when GND > (terminal A) in resistance, GND >(terminal B) in transistor

(NPN).

Moreover, when GND > (terminal B) in transistor (NPN),the parasitic NPN transistor operates with N layer of other

elements adjoining with above-mentioned parasitic diode.

According to potential relation, parasitic element in IC structure can be consequent. The operating of parasitic

element maybe interfere the circuit operation, and become the cause of malfunction and destruction. Therefore,

please pay enough attention not to use it by impressing lower voltage than GND (P substrate) on I/O terminal etc

to operate parasitic element.

Resistance

Transistor（ＮＰＮ）

Ｂ

Ｅ

Ｃ

（TerminalＡ）

（TerminalＢ）

ＧＮＤ

Ｎ

Ｐ

Ｐ^＋

Ｎ

Parasitic element

Ｐsubstrate

ＧＮＤ

Parasitic element

（TerminalＢ）

Ｃ

Ｅ

（TerminalＡ）

Ｂ

Parasitic element

ＧＮＤ

other adjoining elements

Parasitic element

Simple structure example of bipolar IC

www.rohm.com

2009.07 - Rev.A

10/11

Technical Note

BD9207FPS

●Ordering part number

B D

Part No.

Package

Packaging and forming specification

E2: Embossed tape and reel

FPS: TO252S-5

TO252S-5

6.5 0.2

1.2 0.1

0.27 0.1

C0.5

+0.2

Tape

Embossed carrier tape

2000pcs

5.1

−0.1

FIN

Quantity

Direction

of feed

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

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

(

)

0.71

–4

0.27 0.1

0.6 0.2

0.08

0.27 0.1

Direction of feed

Order quantity needs to be multiple of the minimum quantity.

1pin

1.27

0.08

Reel

(Unit : mm)

∗

www.rohm.com

2009.07 - Rev.A

11/11

Notice

N o t e s

No copying or reproduction of this document, in part or in whole, is permitted without the

consent of ROHM Co.,Ltd.

The content speciﬁed herein is subject to change for improvement without notice.

The content speciﬁed herein is for the purpose of introducing ROHM's products (hereinafter

"Products"). If you wish to use any such Product, please be sure to refer to the speciﬁcations,

which can be obtained from ROHM upon request.

Examples of application circuits, circuit constants and any other information contained herein

illustrate the standard usage and operations of the Products. The peripheral conditions must

be taken into account when designing circuits for mass production.

Great care was taken in ensuring the accuracy of the information speciﬁed in this document.

However, should you incur any damage arising from any inaccuracy or misprint of such

information, ROHM shall bear no responsibility for such damage.

The technical information speciﬁed herein is intended only to show the typical functions of and

examples of application circuits for the Products. ROHM does not grant you, explicitly or

implicitly, any license to use or exercise intellectual property or other rights held by ROHM and

other parties. ROHM shall bear no responsibility whatsoever for any dispute arising from the

use of such technical information.

The Products speciﬁed in this document are intended to be used with general-use electronic

equipment or devices (such as audio visual equipment, ofﬁce-automation equipment, commu-

nication devices, electronic appliances and amusement devices).

The Products speciﬁed in this document are not designed to be radiation tolerant.

While ROHM always makes efforts to enhance the quality and reliability of its Products, a

Product may fail or malfunction for a variety of reasons.

Please be sure to implement in your equipment using the Products safety measures to guard

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The Products are not designed or manufactured to be used with any equipment, device or

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More detail product informations and catalogs are available, please contact us.

ROHM Customer Support System

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R0039

BD9207FPS [ROHM]

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