DT8211A [ETC]

LCD Back Light Inverter Drive IC - The DT8211 is a LCD backlight inverter controller for driving CCFL (Cold Cathode Fluorescent Lamp);


型号：	DT8211A
厂家：	ETC
描述：	LCD Back Light Inverter Drive IC - The DT8211 is a LCD backlight inverter controller for driving CCFL (Cold Cathode Fluorescent Lamp) CD
文件：	总10页 (文件大小：225K)
中文：	中文翻译
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DMB Technology

DT8211

LCD Back Light Inverter Drive IC

DT8211

LCD Back Light Inverter Drive IC

Rev1.1 – 11 July 2008

1. General description

The DT8211 is a LCD backlight inverter controller for driving CCFL (Cold Cathode

Fluorescent Lamp). It drives a half bridge topology symmetrically and provides a

near sinusoidal current waveform. It operates at a single-stage topology, constant

frequency PWM (Pulse Width Modulation) mode. The MaxDuty technique achieves

the maximum duty ratio of about 48% and hence can provide better efficiency. A

typical operating frequency ranges from 30kHz to 300kHz, depending on the CCFL

and transformer characteristics. Features such as OLP (Open Lamp Protection) and

SCP (Short Circuit Protection) functions are included. It is available in 18-pin SOPW.

2. Features

n High Efficiency Single Stage Power Conversion

n P- and N-channel MOSFET Driver Included

n Wide Input Supply Voltage Range from 7.5V to 45V

n Maximum Duty ratio of 48%

n Extremely Low Number of External Components

n Extremely Small Size of Board

n Constant Frequency PWM Operation

n High Precision Oscillator

n Analog and Burst Dimming Function Simultaneously

n Analog Dimming Polarity Selectable

n Burst Dimming Polarity Selectable

n Open Lamp Protection Circuit Included

n Output Short Circuit Protection Circuit Included

n 18 Pin SOPW

3. Applications

n LCD Backlight Inverter

n EEFL Inverter

n FFL Inverter

n Advertisement Board

Rev1.1– 11 July 2008

1 of 10

DMB Technology

DT8211

LCD Back Light Inverter Drive IC

4. Package information

Package

Type number

Name

Description

Marking

DT8211

18 SOPW

18 Lead SOP Wide Body

DT8211

5. Typical Application

VCC

VREF

VCC

HOUT

ADIM

BDIM

ADIM

BDIM

RTS

LOUT

GND

DT8211

VCMP

ICMP

CTB

PROT

VFB

IFB

GND

Rev1.1– 11 July 2008

2 of 10

DMB Technology

DT8211

LCD Back Light Inverter Drive IC

6. Pinning information

Top View

VREF

VCC 18

HOUT 17

LOUT 16

GND 15

GND 14

VCMP 13

ICMP 12

VFB 11

ADIM

BDIM

RTS

DT8211

CTB

PROT

IFB 10

Symbol

VREF

I/O

Description

Reference Voltage (VREF) = 6V

ON/OFF Control Pin

ADIM

BDIM

RTS

Analog Dimming Pin (Positive and Negative Mode)

Burst Dimming Pin (Positive and Negative Mode)

Frequency Setting Resistor for Striking PWM Frequency

Frequency Setting Resistor for Main PWM Frequency

Frequency Setting Capacitor for Main PWM Frequency

Frequency Setting Capacitor for Burst Dimming Frequency

Protection Pin

CTB

PROT

IFB

Feedback Input for Current Regulation

Feedback Input for Voltage Regulation

Error Amplifier Output for Current Regulation

Error Amplifier Output for Voltage Regulation

Ground

VFB

ICMP

VCMP

14,15 GND

LOUT

HOUT

VCC

Low Side Gate Driver Output

High Side Gate Driver Output

Supply Voltage

Rev1.1– 11 July 2008

3 of 10

DMB Technology

DT8211

LCD Back Light Inverter Drive IC

7. Absolute maximum ratings

If Military/Aerospace specified devices are required, please contact the DMB technology Sales

Office/Distributors for availability and specifications.

Parameter

Symbol

V_CC

P_D

Value

Unit

Supply Voltage

Power Dissipation

1.9

Operating Ambient Temperature

Operating Junction Temperature

Thermal Resistance Junction to Ambient

Storage Temperature

T_A

-30~+85

-30~+150

66.6

°C

T_J

°C

θ_JA

°C/W

°C

T_STG

-40~+125

8. Electrical characteristics

T_A= 25°C, V_CC= 15V, unless otherwise specified

Parameter

Symbol

Conditions

Min

Typ

Max

Unit

Reference section

Reference Voltage

Max V_REFCurrent

V_REF

I_REF

5.85

6.0

6.15

Voltage Error amplifier section

V. Amp. Transconductance

G_mV

Feedback reference Voltage V_V,REF

1.94

3.05

2.0

3.2

2.06

3.35

Output Clamp Voltage

V_V,CLMP

I_V,SNK

Maximum Sinking Current

Maximum Sourcing Current

High VFB Sinking Current

Current Error amplifier section

I. Amp. Transconductance

μA

I_V,SRC

I_V,SNKH

when VFB > 2.5V

150

200

G_mI

120

1.94

150

2.0

180

2.06

130

Max. Feedback Ref. Voltage V_I,MAX

Maximum Sinking Current

Maximum Sourcing Current

I_I,SNK

I_I,SRC

100

μA

Rev1.1– 11 July 2008

4 of 10

DMB Technology

DT8211

LCD Back Light Inverter Drive IC

8. Electrical characteristics

T_A= 25°C, V_CC= 15V, unless otherwise specified

Parameter

Symbol

Conditions

Min

Typ

Max

Unit

Main oscillator section

RT Voltage

V_RT

1.96

2.0

100

2.04

103

51.5

3.2

CT Oscillation Frequency

Main Oscillation Frequency

Triangular High Voltage

Triangular Low Voltage

Burst oscillator section

Burst Oscillation Frequency

Triangular High Voltage

Triangular Low Voltage

Dimming section

F_CT

kHz

when R_T>20kΩ

F_MAIN

V_HM

V_LM

48.5

2.8

3.0

1.2

1.0

1.4

F_oscB

V_HB

V_LB

when R_T>20kΩ

291

1.9

0.7

300

2.0

0.8

309

2.1

0.9

ADIM Input Impedance

BDIM Input Impedance

ADIM Int. Bias Voltage

BDIM Int. Bias Voltage

Protection section

R_ADIM

100

2.5

120

2.6

KΩ

R_BDIM

V_ADIM,B

V_BDIM,B

2.4

Init. PROT Discharging I.

PROT Charging Current

PROT Threshold Voltage

IFB Open Lamp Detect V.

ICMP Striking Mode V.

General

I_PROT,INI

I_PROT,CG

V_PROT

μA

0.35

2.8

0.65

3.2

0.5

3.0

0.75

3.5

0.65

3.2

V_OLP,IFB

V_STK,ICMP

0.85

3.8

when IFB<0.75V

Enable On Voltage

V_EN,ON

V_EN,OFF

I_CC

2.0

Enable Off Voltage

0.8

Quiescent Current

7.0

Maximum Oscillation Duty

Output section

D_MAX

P-CH Output High Voltage

P-CH Output Low Voltage

N-CH Output High Voltage

N-CH Output Low Voltage

V_POH

V_POL

V_NOH

V_NOL

I_SINK=200μA

I_SOURCE=200μA

I_SINK=200μA

I_SOURCE=200μA

V_CC- 0.5

V_CC- 14

10.0

V_CC- 0.1

V_CC- 12

12.0

0.1

V_CC

V_CC- 10

14.0

0.5

Rev1.1– 11 July 2008

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DMB Technology

9. Block Diagram

VFB 11

DT8211

LCD Back Light Inverter Drive IC

VCMP ICMP

VCC

6.0V

VREF

Startup

and

Voltage Reference

Fast Response

Internal Bias

OTA

2V Ref.

17 HOUT

16 LOUT

Pulse Distributor

and

Dead Time

Generator

COMP

IFB 10

3.0V

1.2V

OTA

LTA

Positive & Negative

Control Block

ADIM

Burst

On/Off

2V Ref.

Open Lamp

Detection

and

High Precision

Dual Oscillator

Block

VREF

Frequency

Shift Block

0.5uA

(Main/Burst)

2.0V

0.8V

2.0V

COMP

15 GND

14 GND

3V Ref.

COMP

Positive & Negative

Control Block

BDIM

RTS

CTB

PROT

10. Functional Description

Internal Regulator

To supply a stable power to internal and external circuit, a high precise regulator is

included. It makes 6.0V over the full range of input supply voltage. This also supplies

a stable voltage to internal analog critical circuit, to make stable operation. VREF is

an output of internal regulator, and can supply over 30mA to external circuit.

Chip Enable

When EN pin is over V_EN,ON, the internal regulator is turned on. Therefore internal

and external circuits begin to operate. Since it has over 100mV hysteresis,

unpredictable operation is protected.

Main Frequency Oscillator

To generate clear PWM pulse, DT8211 includes a precise triangular waveform

generator circuit. The voltage of RT pin is fixed at 2.0V and the current of RT pin is

flow through the resistor which is connected between RT pin and GND. This current

makes charging and discharging current of a capacitor which is connected to CT pin

and GND. Triangular wave is generated at CT pin by charging and discharging

(repeated operation) to this capacitor. This triangular wave is one of reference signal

to generate PWM. The frequency of triangular wave can be calculated approximately

as below and is 2 times of lamp frequency.

0.232

f_Main[Hz] =

R_T•C_T

Rev1.1– 11 July 2008

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DMB Technology

DT8211

LCD Back Light Inverter Drive IC

10. Functional Description (Continued)

Striking Frequency

Striking frequency is generated by increasing charging and discharging current of a

capacitor (CT). RTS pin is normally high impedance, but it goes low when DT8211 is

in striking mode. If a resistor is connected between RTS and RT, a striking frequency

can be generated by increased current and the equation is as below.

0.228(R_T+R_TS)

f_Striking[Hz] =

R_T• R_TS•C_T

Burst Frequency Oscillator

To generate clear PWM pulse, DT8211 includes a precise triangular waveform

generator circuit. The voltage of RT pin is fixed at 2.0V and the current of RT pin is

flow through the resistor which is connected between RT pin and GND. This current

makes charging and discharging current of a capacitor which is connected to CTB pin

and GND. Triangular wave is generated at CTB pin by charging and discharging

(repeated operation) to this capacitor. This triangular wave is one of reference signal

to generate PWM. The frequency of triangular wave can be calculated approximately

as below.

0.11

f_Burst[Hz] =

R_T•C_TB

Analog Dimming

DT8211 includes three kinds of dimming method. One is analog dimming, burst

dimming and pulse dimming. Analog dimming command feeds DC level to ADIM pin

which is a positive input of internal error amplifier. When 0V<V_ADIM<2.0V, DT8211

operates in positive polarity mode, but when 3.0V<V_ADIM<5.0V, DT8211 operates in

negative polarity mode as below figure.

The negative input of error amplifier for current is IFB pin, and control loop is

operated to make IFB level equal to ADIM level. The output of error amplifier for

current, which is ICMP pin, is directly connected to main PWM generator.

Rev1.1– 11 July 2008

7 of 10

DMB Technology

DT8211

LCD Back Light Inverter Drive IC

10. Functional Description (Continued)

Burst Dimming

DT8211 includes three kinds of dimming method. One is analog dimming, burst

dimming and pulse dimming. Burst dimming command feeds DC level to BDIM pin

which is an input of internal PWM generator. When 0V<V_BDIM<2.0V, DT8211 operates

in positive polarity mode, but when 3.0V<V_BDIM<5.0V, DT8211 operates in negative

polarity mode as below figure.

Burst PWM is generated using BDIM and triangular wave of CTB. The rising and

falling slopes of BDIM operation are adjusted by capacitor which is connected

between ICMP pin and GND. The source and sink currents of ICMP are 100uA. We

recommend 300usec as rising and falling time.

Pulse Dimming

DT8211 includes three kinds of dimming method. One is analog dimming, burst

dimming and pulse dimming. In this mode, PWM pulse of pulse dimming feeds to

BDIM pin and a resistor must be connected between CTB and GND. When the pulse

swings 0V to 2V, DT8211 operates in positive polarity mode, but when the pulse

swings 3V to 5V, DT8211 operates in negative polarity mode.

To operate pulse dimming mode, CTB must be a constant level. So a resistor is

recommended between CTB and GND, and its value which makes CTB level to about

1.0V is recommended as below equation.

R_{CTB ,PDIM}= 3.5×R_T

Main PWM Generator

The main PWM pulse is generated with ICMP, VCMP and CT. ICMP and VCMP are

connected to comparator negative inputs of PWM generator, and CT is connected to

comparator positive input of PWM generator. CT decides PWM frequency and ICMP

and VCMP decide PWM Duty. Output duty of main PWM is limited approximately 48%

when main frequency is 50kHz to prevent shoot-through of Power FETs.

Rev1.1– 11 July 2008

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DMB Technology

DT8211

LCD Back Light Inverter Drive IC

10. Functional Description (Continued)

Protection (OLP, SCP)

Abnormal status is detected by IFB level. If IFB level goes under 0.75V, DT8211

became protection mode. This mode means that one or more of current feedback

levels is very low. To change to normal operating mode, IFB level must be higher

than 0.75V. In protection mode, a capacitor which is connected PROT pin is charged

by 0.5uA. If PROT pin is over 3.0V, DT8211 will shutdown the outputs. To restart

DT8211 after shutdown, EN or VCC must be low and go high. The time of protection

is as below.

T_PROT[sec] = 6×10⁶⋅C_PROT

Striking Mode

Striking mode is a part of abnormal status. This mode is detected by IFB level and

ICMP level. If IFB level goes under 0.75V and ICMP level goes over 3.5V, DT8211

became striking mode. (Of course striking mode must be occurred in protection

mode.) This mode means lamp open status, so DT8211 try to increase output

voltage by shifting operating frequency. In this mode, RTS goes to 0V and burst

dimming signal is ignored. The striking frequency is decided as above description.

OVP (Over Voltage Protection)

OVP function is implemented by internal voltage error amplifier. The reference

voltage is 2.0V and in over voltage status, VFB pin is regulated as 2.0V.

Soft Start

After enabling DT8211, all capacitors which are connected to DT8211 are charged to

make startup. A capacitor which is connected to VCMP must be chosen as a large

value such as 100~300nF for soft start.

Gate Driver

DT8211 includes P channel and N channel gate drivers. The swing voltage of driver

output is approximately 12V and DT8211 can drive directly PowerFETs without

external component.

Rev1.1– 11 July 2008

9 of 10

DMB Technology

DT8211

LCD Back Light Inverter Drive IC

11. Package outline

18-Lead SOPW

12. Important notices

n This products and its characteristic can be added or changed without notice.

Before considering use or application, you’d better consult the D.M.B Technology

Co., Ltd.

n No part of this publication may be reproduced or transmitted or copied in any

form or by any means without permission of D.M.B Technology.

n Although our product has internal protective circuit, you’d better adopt safety

circuits or measures externally to prevent undesired probabilistic device failure.

n D.M.B technology always strives to make a high quality and high reliability

products.

13. Contact information

For technical information

For sales information

icmozart@dmbtech.com

sales@dmbtech.com

For additional information

http://www.dmbtech.com

Rev1.1– 11 July 2008

10 of 10

DT8211A [ETC]

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