ROHM BD1206GUL Technical data

LED Drivers for LCD Backlights

Backlight LED Driver for Small LCD Panels (Charge Pump Type)

BD1206GUL

●Description

BD1206GUL is 5ch or 6ch parallel LED driver for the portable instruments. This IC is equipped with an automatic transition charge pump and 16-step LED drivers. Hence this IC realizes high efficiency and high accuracy drive of LEDs. Additionally, this IC can synchronize LED drive with external PWM signal. This IC is best suited to turn on white LEDs that require high-accuracy LED brightness control.

●Features

1) 5ch or 6ch parallel LED driver is mounted

2) 16-step LED current adjust function

3) LED current matching is 5% or less

4) Driving control via a single-line digital control interface

5) Automatic transition charge pump type DC/DC converter (×1, ×1.5, ×2)

6) High efficiency achieved (Maximum over 93%)

7) It transits for the most suitable power operating by the LED terminal process of the 6th light when only 5 lights driving

8) Various protection functions such as output voltage protection and thermal shutdown circuit are mounted.

9) The input external PWM is possible and the back light control interlocked with the motion picture is possible.

10) Package: VCSP50L2 (Thick 0.55mm MAX, Pin pitch 0.5mm) CSP15pin package

●Absolute Maximum Ratings (Ta=25ºC)

Parameter Symbol Ratings Unit

Power supply voltage VMAX 7 V

No.10040EAT08

Input voltage ( EN , PWMIN ) Vdin GND-0.3 ~ VBAT+0.3 V

Power dissipation Pd 900 mW

Operating temperature range Topr -30 ~ +85 ºC

Storage temperature range Tstg -55 ~ +150 ºC

(Note) Power dissipation deleting is 7.2mW/ ºC, when it’s used in over 25 ºC.(It’s deleting is on the board that is ROHM’s standard)

Dissipation by LSI should not exceed tolerance level of Pd.

●Operating Conditions (Ta = -30 ~ 85

Parameter Symbol Limits Unit

Operating power supply voltage VBAT 2.7 ~ 5.5 V

*This chip is not designed to protect itself against radioactive rays. *This material may be changed on its way to designing. *This material is not the official specification.

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●Electrical Characteristics (Unless otherwise noted, Ta = +25oC, VBAT=3.6V)

Parameter Symbol

Current Consumption

Quiescent Current Iq - 0.1 1 μA EN=0V

Current Consumption1 Idd1 - 62 64 mA

Current Consumption2 Idd2 - 123 126 mA

Charge Pump

Oscillator frequency fOSC 0.56 0.85 1.14 MHz

Current Source

LED maximum current ILED-max 18 20 22 mA VBAT≥3.2V

LED current accuracy ILED-diff - - 10.0 %

LED current matching ILED-match - 0.5 5.0 %

LED control voltage VLED - 0.15 0.25 V

Logic control terminal

Min. Typ. Max.

Limits

Units Condition

x 1.0 Mode Include LED current (60mA) x 2.0 Mode Include LED current (60mA)

LED current setting is 10.0mA, LED terminal voltage is 1.0V LED current setting is 10.0mA, LED terminal voltage is 1.0V Minimum voltage from LED1 to LED6 pins

Technical Note

Low threshold voltage VIL - - 0.4 V EN, PWMIN

High threshold voltage VIH 1.4 - - V EN, PWMIN

High level Input current IIH - 0 1 μA EN = VBAT, PWMIN = VBAT

Low level Input current IIL -1 0 - μA EN = 0V, PWMIN = 0V

Minimum EN High time THI 0.05 - 100 μs Described in Fig.5

Minimum EN Low time TLO 0.3 - 100 μs Described in Fig.5

EN Off Timeout TOFF 1 - - ms Described in Fig.5

Latch time TLAT 1 - - ms Described in Fig.5

Access available time Tacc 1 - 5 ms Described in Fig.5

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●Block Diagram

VBAT

Charge Pump

Mode Control

PWMIN

Enable/

Brightness

Control

GND

●Pin Configuration [Bottom View]

Technical Note

C2N

C1P

C1N

×1, ×1.5, ×2

Charge pump

Over Voltage

Protect

OSC

TSD

LED6 DET

Current

DAC

Pin number 14pin

Fig. 1 Block Diagram

C2P

Vout Control

VOUT

LED1

LED2

LED3

LED4

LED5

LED6

D LED1 LED2 PWMIN VBAT

C LED3 LED4 EN C1N

BLED5

A LED6 GND VOUT C2P

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index

C2N C1P

1 2 3 4

Fig. 2 Pin Configuration

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●Package Outline

Technical Note

1206

Lot No.

( UNIT : mm )

Fig. 3 Package Dimension

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●Pin Descriptions

Pin No. Terminal No. Pin Name In/Out Type Function

1 D4 VBAT - A Power supply

2 B4 C1P In/Out A Flying capacitor pin positive (+) side

3 C4 C1N In/Out B Flying capacitor pin negative (-) side

4 A4 C2P In/Out A Flying capacitor pin positive (+) side

5 B3 C2N In/Out B Flying capacitor pin negative (-) side

6 A3 VOUT Out A Charge pump output

7 C3 EN In C ON/OFF and dimming control

8 D1 LED1 Out B LED current driver output 1

9 D2 LED2 Out B LED current driver output 2

10 C1 LED3 Out B LED current driver output 3

11 C2 LED4 Out B LED current driver output 4

12 B1 LED5 Out B LED current driver output 5

13 A1 LED6 Out A LED current driver output 6

14 D3 PWMIN In C PWM Control

15 A2 GND - D GND

●Pin ESD Type

Type A

Type B

Type C

VBAT

Technical Note

VBAT

PAD

GND

PAD

GND

PAD

GND

Type D

BAT

PAD

Fig. 4 Pin ESD Type

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●Separate Function Description

(1) LED driver

a) Register access control protocol

LED current is controlled by only EN terminal. It is possible to access the register inside of this chip by using the protocol below. Accessing the registers with using this protocol operates LED driver ON/OFF and selecting the mode. Moreover, MAX current can be outputted without Clock input to EN terminal by holding H zone of fixed time after EN terminal starting.

< When setting current level >

acc

pulse

1 2

LED Current Setting

(Notes) T

< When starting by MAX setup >

LED Current Setting

(Note) ・In the case of N > 16, BD1206GUL selects the mode of N = 16. ・LED current is changed by the pulse of EN pin. Be careful to noise of EN signal. ・Reset BD1206GUL when the set is unusual. (Keep EN=L over Toff time.)

accMIN

accMA

LED Current

pulse

0 0

LAT

(N≦16)

n 0 0

< T

Please input a pulse on this condition

accMAX

OFF

１

n-1

< T

Fig.5 Register access protocol

LAT

ac c

16pulse 15pulse 14pulse

OFF

LAT

0.125mA

0.25mA

LAT

13pulse

0.5mA

LAT

1mA

Fig.6 Slope control example

Technical Note

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b) LED current level

The interface records rising edges of the EN pin and decodes them into 16 different indicated in following table.

Data Output current [mA] Data Output current [mA]

(2) Charge pump

a) Description of operations

Pin voltage comparison takes place at Vout control section, and then Vout generation takes place so that the LED cathode voltage with the highest Vf is set to 0.15V. A boost rate is changed automatically to a proper one at the Charge Pump Mode Control section so that operation can take place at possible low boost rate. In addition, when the VOUT output is short-circuited to GND, the leak current is suppressed via the over current protection function.

b) Soft start function

BD1206GUL have a soft start function that prevents the rush current.

1 20.0 9 5.0

2 17.0 10 4.0

3 14.0 11 3.0

4 12.0 12 2.0

5 10.0 13 1.0

6 8.5 14 0.5

7 7.0 15 0.25

8 6.0 16 0.125

EN/LED*

VOUT

LED

OFF

Technical Note

c) Automatic boost rate change

The boost rate automatically switches to the best mode.

* (×1 mode  ×1.5 mode) or (×1.5 mode  ×2 mode)

If a battery voltage drop occurs BD1206GUL cannot maintain the LED constant current, and then mode transition begins.

* (×1.5 mode  ×1 mode) or (×2 mode  ×1.5 mode)

If a battery voltage rise occurs, VOUT and VBAT detection are activated, and then mode transition begins.

(3) UVLO (Under Voltage Lock Out)

If the input voltage falls below 2.2V(Typ.), BD1206GUL is shut down to prevent malfunction due to ultra-low voltage.

(4) OVP (Over Voltage Protection)

This circuit protects this IC against damage when the C/P output voltage (VOUT) rises extremely for some external factors.

(5) Thermal shutdown (TSD)

To protect this IC against thermal damage or heat-driven uncontrolled operations, this circuit turns off the output if the chip temperature rises over 175ºC. In addition, it turns on the output if the temperature returns to the normal temperature. Because the built-in thermal protection circuit is intended to protect the IC itself, the thermal shutdown detection temperature must be set to below 175ºC in thermal design.

Soft Start Ordinal mode

Fig.7 Soft Start

* EN/LED is an internal enable

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(6) Power sequence

EN signal must be released after VBAT voltage enough rise up. Prohibit the VBAT rise up during EN=”H”.

Technical Note

BAT

(7) PWM control

PWM control by the external terminal (PWMIN) is possible. It becomes PWM operation, which used LED current by a register setup as the base and is the best for the brightness compensation by external control.If the application with is not use PWM, PWMIN pin must be short to VBAT.

PW MIN input

LED C urrent

It is possible to make it a PWMIN input before EN/LED* is “H”. A PWM drive becomes effective after the time of LED current standup.

When rising during PWM operation, as for the standup time of VOUT, only the rate of PWM Duty becomes late. Appearance may be influenced when extremely late frequency and extremely low Duty are inputted. Please secure over 120 μs “H” sections at the time of PWM pulse Force.

EN/LED* is an internal enable signal

EN/LED*

VOUT

Inte rnal S oft-Sta rt Tim e

PW MIN input

LED Current

Fig.9 External PWM input solution

Fig.8 Power sequence

Non-PW M

PWMIN LED Current

L Compulsion OFF

H Normal operation

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●Application Circuit Example (6 light with PWM)

C1=1μF

Battery

VBAT

Cin

=1μF

C1N

×1, ×1.5, ×2

Charge pump

Charge Pump

Mode Control

From CPU

From LCM

PWMIN

Enable/

Brightness

Control

GND

Fig.10 Application Circuit Example 1

●Application Circuit Example (5 light with PWM)

C1=1μF

Battery

VBAT

Cin

=1μF

C1N

×1, ×1.5, ×2

Charge pump

Charge Pump

Mode Control

From CPU

From LCM

PWMIN

Enable/

Brightness

Control

GND

Fig.11 Application Circuit Example 2

C2=1μF

C2N

C1P

Over Voltage

Protect

OSC

TSD

LED6 DET

Current

DAC

C2=1μF

C2N

C1P

Over Voltage

Protect

OSC

TSD

LED6DET

Current

DAC

Technical Note

C2P

VOUT

Cout

=1μF

Vout Control

LED1

LED2

LED3

LED4

LED5

LED6

C2P

VOUT

Cout

=1μF

Vout Control

LED1

LED2

LED3

LED4

LED5

LED6

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●Application Circuit Example (6 light without PWM)

C1=1μF

Battery

VBAT

Cin

=1μF

C1N

×1, ×1.5, ×2

Charge pump

Over Voltage

Charge Pump

Mode Control

From CPU

Enable/

Brightness

Control

PWMIN

Battery

Current

DAC

GND

Fig.12 Application Circuit Example 3

C2=1μF

C2N

C1P

Protect

OSC

TSD

LED6 DET

Technical Note

C2P

VOUT

Cout

=1μF

Vout Control

LED1 LED2

LED3

LED4

LED5

LED6

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●Notes for use

(1) Absolute Maximum Ratings

An excess in the absolute maximum ratings, such as supply voltage, temperature range of operating conditions, etc., can break down devices, thus making impossible to identify breaking mode such as a short circuit or an open circuit. If any special mode exceeding the absolute maximum ratings is assumed, consideration should be given to take physical safety measures including the use of fuses, etc.

(2) Power supply and ground line

Design PCB pattern to provide low impedance for the wiring between the power supply and the ground lines. Pay attention to the interference by common impedance of layout pattern when there are plural power supplies and ground lines. Especially, when there are ground pattern for small signal and ground pattern for large current included the external circuits, please separate each ground pattern. Furthermore, for all power supply pins to ICs, mount a capacitor between the power supply and the ground pin. At the same time, in order to use a capacitor, thoroughly check to be sure the characteristics of the capacitor to be used present no problem including the occurrence of capacity dropout at a low temperature, thus determining the constant.

(3) Ground voltage

Make setting of the potential of the ground pin so that it will be maintained at the minimum in any operating state. Furthermore, check to be sure no pins are at a potential lower than the ground voltage including an actual electric transient.

(4) Short circuit between pins and erroneous mounting

In order to mount ICs on a set PCB, pay thorough attention to the direction and offset of the ICs. Erroneous mounting can break down the ICs. Furthermore, if a short circuit occurs due to foreign matters entering between pins or between the pin and the power supply or the ground pin, the ICs can break down.

(5)Operation in strong electromagnetic field

Be noted that using ICs in the strong electromagnetic field can malfunction them.

(6)Input pins

In terms of the construction of IC, parasitic elements are inevitably formed in relation to potential. The operation of the parasitic element can cause interference with circuit operation, thus resulting in a malfunction and then breakdown of the input pin. Therefore, pay thorough attention not to handle the input pins, such as to apply to the input pins a voltage lower than the ground respectively, so that any parasitic element will operate. Furthermore, do not apply a voltage to the input pins when no power supply voltage is applied to the IC. In addition, even if the power supply voltage is applied, apply to the input pins a voltage lower than the power supply voltage or within the guaranteed value of electrical characteristics.

(7) External capacitor

In order to use a ceramic capacitor as the external capacitor, determine the constant with consideration given to a degradation in the nominal capacitance due to DC bias and changes in the capacitance due to temperature, etc.

(8)Thermal shutdown circuit

This LSI builds in a thermal shutdown circuit. When junction temperatures become detection temperature or higher, the thermal shutdown circuit operates and turns a switch OFF. The thermal shutdown circuit, which is aimed at isolating the LSI from thermal runaway as much as possible, is not aimed at the protection or guarantee of the LSI. Therefore, do not continuously use the LSI with this circuit operating or use the LSI assuming its operation.

(9) Thermal design

Perform thermal design in which there are adequate margins by taking into account the permissible dissipation (Pd)in actual states of use.

(10) About the pin for the test, the un-use pin

Prevent a problem from being in the pin for the test and the un-use pin under the state of actual use. Please refer to a function manual and an application notebook. And, as for the pin that doesn't specially have an explanation, ask our company person in charge.

(11) About the rush current

For ICs with more than one power supply, it is possible that rush current may flow instantaneously due to the internal powering sequence and delays. Therefore, give special consideration to power coupling capacitance, power wiring, width of ground wiring, and routing of wiring.

(12) About this document

This document is the design materials to design a set. So, the contents of the materials aren't always guaranteed. Please design application by having fully examination and evaluation include the external elements.

Technical Note

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●Ordering part number

Technical Note

B D 1 2 0 6 G U L - E 2

Part No. Part No.

VCSP50L2

(BD1206GUL)

1PIN MARK

15-φ0.25±0.05

0.05

(φ0.15)INDEX POST

0.25±0.05

D C B A

2.00±0.05

P=0.5×3

0.06 S

2.00±0.05

0.55MAX

0.1±0.05

0.25±0.05

P=0.5×3

(Unit : mm)

Package

GUL: VCSP50L2

Embossed carrier tape(heat sealing method)Tape

Quantity

Direction of feed

3000pcs E2

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

Reel

Packaging and forming specification E2: Embossed tape and reel

1pin

Order quantity needs to be multiple of the minimum quantity.

∗

Direction of feed

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Notes

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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 specied 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 specied 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.

Notice

The Products specied in this document are intended to be used with general-use electronic equipment or devices (such as audio visual equipment, ofce-automation equipment, communication devices, electronic appliances and amusement devices).

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ROHM BD1206GUL Technical data

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