Rohm BH1730FVC Technical Note

Ambient Light Sensor ICs

Digital 16bit Serial Output Type Ambient Light Sensor IC

BH1730FVC

●Descriptions

BH1730FVC is a digital Ambient Light Sensor IC for I data for adjusting LCD backlight power of TV, mobile phone. It is possible to detect very wide range light intensity. (0.008 65535 lx ).

●Features

●Applications

●Absolute Maximum Ratings

●Operating Conditions

2

1) I

2) There are two outputs that peaks of a spectrum response are in visible light (Type0) and in infrared light (Type1).

3) Illuminance to Digital Converter

4) Very wide range and High resolution. ( 0.008 - 65535 lx )

5) Low Current by power down function

6) 50Hz / 60Hz light noise reject-function

7) Correspond to 1.8V logic input interface

8) Light source dependency is little by calculating with Type0 and Type1. ( ex. Incandescent Lamp. Fluorescent Lamp. Halogen Lamp. White LED. Sun Light )

9) Interrupt function is available.

10) Adjustable measurement result for influence of optical window ( It is possible to detect min. 0.001 lx, max. 100000 lx by using this function. )

11) Small measurement variation (+/- 15%)

12) Built in power on reset circuit.

LCD TV, Mobile phone, NOTE PC, Portable game machine, Digital camera, Digital video camera, PDA, LCD display

C bus Interface ( f / s Mode Support, Slave address "0101001". )

Parameter Symbol Limits Units

Supply Voltage VCCmax

INT , SDA, DVI, SCL, Terminal Voltage V Operating Temperature Topr -40～70 ℃ Storage Temperature Tstg -40～100 ℃

SDA, INT Sink Current Imax 7 mA

Power Dissipation Pd 260※ mW

※ 70mm × 70mm × 1.6mm glass epoxy board. Derating in done at 3.47mW/℃ for operating above Ta=25℃.

Parameter Symbol Min. Typ. Max. Units

VCC Voltage Vcc 2.4 3.0 3.6 V

I2C Reference Voltage VDVI 1.65 - VCC V

2

C bus interface. This IC is the most suitable to obtain the ambient light

4.5 V

7 V

max, V

INT

SDA

max, V

DVI

SCL

max

No.11046EAT13

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●Electrical Characteristics ( VCC = 3.0V, VDVI = 3.0V, Ta = 25℃, unless otherwise noted )

Parameter Symbol

Min. Typ. Max.

Limits

Units Conditions

Ev = 100 lx

Supply Current Icc1 － 150 200 uA

CONTROL register(00h) = ”03h” and the other registers are default.

Powerdown Current Icc2 － 0.85 1.5 uA

No input Light All registers are default.

Peak Wave Length in Type0 λp0 － 600 － nm Visible light response

Technical Note

※

Peak Wave Length in Type1 λp1 － 840 － nm Infrared light response

※

ADC count value in Type0 D1k_0 1020 1200 1380 count

ADC count value in Type1 D1k_1 153 180 207 count

EV = 1000 lx TIMING register(01h) = “DAh” GAIN register(07h) = “00h” EV = 1000 lx TIMING register(01h) = “DAh” GAIN register(07h) = “00h” No input Light

Dark ( 0 lx ) Sensor out in Type0 S0_0 0 0 2 count

TIMING register(01h) = “DAh” GAIN register(07h) = “00h” No input Light

Dark ( 0 lx ) Sensor out in Type1 S0_1 0 0 2 count

TIMING register(01h) = “DAh” GAIN register(07h) = “00h”

Gain X1 resolution in Type0 rG1 － 0.83 － lx/count TIMING register(01h) = “DAh”

Gain X2 resolution in Type0 rG2 － 0.42 － lx/count TIMING register(01h) = “DAh”

Gain X64 resolution in Type0 rG64 － 0.014 － lx/count TIMING register(01h) = “DAh”

Gain X128 resolution in Type0 rG128 － 0.007 － lx/count TIMING register(01h) = “DAh”

Measurement Time tmt1 － 100 150 ms TIMING register(01h) = “DAh”

Incandescent / Fluorescent ratio by calculating with Type0 and

rIF － 1 － times EV = 1000 lx

Type1 INT Output ‘L’ Voltage VINT 0 － 0.4 V IINT = 3 mA

DVI Input ‘L’ Voltage VDVL －－ 0.4 V

SCL, SDA Input ‘H’ Voltage 1 VIH1 0.7*DVI －－ V DVI ≧ 1.8V

1

※

1

※

1

※

1

※

SCL, SDA Input ‘H’ Voltage 2 VIH2 1.26 －－ V 1.65V ≦ DVI ＜1.8V

SCL, SDA Input ‘L’ Voltage 1 VIL1 －－ 0.3*DVI V DVI ≧ 1.8V

SCL, SDA Input ‘L’ Voltage 2 VIL2 －－ DVI–1.26 V 1.65V ≦ DVI ＜ 1.8V

SCL, SDA, INT Input ‘H’ Current IIH －－ 10 µA

SCL, SDA, INT Input ‘L’ Current IIL －－ 10 µA

I2C SCL Clock Frequency fSCL －－ 400 kHz

I2C Bus Free Time tBUF 1.3 －－ µs

I2C Hold Time ( repeated ) START Condition I2C Set up time for a Repeated START Condition I2C Set up time for STOP Condition

tHDSTA 0.6 －－ µs

tSUSTA 0.6 －－ µs

tSUSTO 0.6 －－ µs

I2C Data Hold Time tHDDAT 0 － 0.9 µs

I2C Data Setup Time tSUDAT 100 －－ ns

I2C ‘L’ Period of the SCL Clock tLOW 1.3 －－ µs

I2C ‘H’ Period of the SCL Clock tHIGH 0.6 －－ µs

I2C SDA Output ‘L’ Voltage VOL 0 － 0.4 V IOL = 3 mA

※1 White LED is used as optical source.

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Technical Note

●Reference Data

1.2

1

0.8

0.6

Ratio

0.4

0.2

0

400 500 600 700 800 900 1000 1100

Wavelength [ nm ]

Fig.1 Spectral Response of Type0

(visible light peak)

10

8

6

4

Measurement Result

2

0

-40-20 0 20406080

Fig.4 Dark Response of Type0

Ta [ ℃ ]

1.2

1

0.8

0.6

Ratio

0.4

0.2

0

-40-20020406080

Fig.7 ADC count value in Type0

Temperature Dependency

Ta [ ℃ ]

10

1

ICC @ POWER DOWN [ uA

0.1

-40-200 20406080

Ta [ ℃ ]

Fig.10 Power down ICC@0Lx

Temperature Dependency

1.2

1

0.8

0.6

Ratio

0.4

0.2

0

400 500 600 700 800 900 1000 1100

Wavelength [ nm ]

Fig.2 Spectral Response of Type1

(infrared light peak)

1.2

1

0.8

0.6

Ratio

0.4

0.2

0

-90 -60 -30 0 30 60 90

1pin

-

Ang le [ deg ]

+

Fig.5 Directional Characteristics 1

Fl uoresc ent

Lig ht

Incandes cent

Lig ht

Halogen

Lig ht

Kripton Li ght

White LED

00.511.52

Ratio

Fig.8 Light Source Dependency in calculation from Type0 and Type1.

( Fluorescent Light is set to '1' )

1.2

1

0.8

0.6

Ratio

0.4

0.2

0

2 2.5 3 3.5 4

DVI=1.8V

VCC [ V ]

Fig.11 Measurement Result

VCC Dependency

100000

10000

1000

100

Measurement Resu

10

1

1 10 100 1000 10000 100000

Illumi nance [ l x ]

Fig.3 Illuminance -Measurement

Result of Type0, Gain 1X, ITIME=DAh

1.2

1

0.8

0.6

Ratio

0.4

0.2

0

-90 -60 -30 0 30 60 90

Ang le [ deg ]

-

1pin

-

+

Fig.6 Directional Characteristics 2

300

250

200

150

100

ICC @ Measuremen

50

0

2 2.5 3 3.5 4

VCC [ V ]

Fig.9 VCC - ICC

( During measurement )

1.2

1

0.8

0.6

Ratio

0.4

0.2

0

1.5 2 2.5 3 3.5

VCC=3V

DVI [ V ]

Fig.12 Measurement Result

DVI Dependency

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BH1730FVC

●Block Diagram

●Block Diagram Descriptions

・PD

Photo diodes (PD) with peaks in visible light and in infrared light.

・AMP

Integration OPAMP for converting from PD current to voltage.

・ADC

AD converter for obtainment digital 16bit data.

・ADC Logic + I

2

C Interface + INT Interface

Ambient light calculation logic and I

・OSC

Internal oscillator ( typ. 360kHz ). It is clock for internal logic.

・POR

Power on reset. All register is reset after VCC is supplied. Please refer P14 (Caution of power on reset function).

AMP

PD for visible light

AMP

PD for infrared light

2

C Bus Interface and Interrupt function Interface.

VCC

ADC

OSC

GND

DVI

ADC Logic

+

2

I

C Interface

+

INT Interface

INT

Technical Note

SCL

SDA

POR

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BH1730FVC

Technical Note

●I2C Bus Access and Write / Read format

2

C Bus interface timing chart

1 ) I

Write measurement command and Read measurement result are done by I specification of I

2

C Bus interface, and follow the formally timing chart.

2

C Bus interface. Please refer the formally

SDA

tf

t

LOW

t

tr

SU ; DAT

t

f

t

HD ; STA

SCL

S

t

HD ; STA

t

HD ; DAT

t

HIGH

t

SU ; STA

Sr

t

SU;STO

2) Main write Format

1. Case of “Write to Command Register”

ST

Slave Address

0101001

W

0

ACK

Data to Command Register

1XXXXXXX

2. Case of “Write to Data Register”

ST

Slave Address

0101001

W

0

ACK

Data specified at register address field

0XXXXXXX

Data specified at register address

field +1

ACK

・・・ ACK

Data specified at register address

field +N

※ The register address that set in Command register is used.

3. Case of "write to data register after write to Command Register"

ST

Slave Address

0101001

W

0

ACK

Data to Command Register

1XXXXXXX

Data specified at register address

field

ACK

・・・ ACK

Data specified at register address

field +N

3) Main read Format

ST

Slave Address

0101001

R

ACK Data specified at register address field

1

Data specified at register

address field +1

ACK ・・・ ACK

Data specified at register

address field +N

※ The register address that set in Command register is used.

from master to slave

from slave to master

BH1730FVC operates as I2C bus slave device.

※

Please refer formality I2C bus specification of NXP semiconductor

※

BH1730FVC continues to write or read data with address increments until master issues stop condition. Read cycle is 00h - 01h - 02h - 03h - 04h - 05h - 06h – 07h – 12h – 14h – 15h – 16h – 17h - 00h ………

tr

t

BUF

P

ACK

SP

ACK

SP

ACK

SP

ACK

NACK SP

S

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BH1730FVC

●Measurement Procedure

●Explanation of Asynchronous reset and Software reset command.

1) Asynchronous reset All registers are reset and BH1730FVC becomes power down during DVI = 'L'. Initial reset is not necessary, because power on reset function is included in this product.

2) Software reset command All registers are reset and BH1730FVC becomes power down by Software reset command.

Power supply

Power Down

POWER bit = H and ADC_EN bit =H

Measurement

ONE_TIME bit = Ｈ?

No

INT_STOP bit = H and INT is active?

No

Initial state is Power Down mode after VCC and DVI supply.

Yes

State Transition by I2C write-command.

Automatically State Transition

Technical Note

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●Command set

Address Type Register name Register function

-- W COMMAND Specifies register address or set special command

00h RW CONTROL Operation mode control

01h RW TIMING Light integration time control

02h RW INTERRUPT Interrupt function control

03h RW THLLOW Low byte of low interrupt threshold setting

04h RW THLHIGH High byte of low interrupt threshold setting

05h RW THHLOW Low byte of high interrupt threshold setting

06h RW THHHIGH High byte of high interrupt threshold setting

07h RW GAIN Gain control

12h R ID Part number and Revision ID

14h R DATA0LOW ADC Type0 low byte data register

15h R DATA0HIGH ADC Type0 high byte data register

16h R DATA1LOW ADC Type1 low byte data register

17h R DATA1HIGH ADC Type1 high byte data register

○COMMAND

7 6 5 4 3 2 1 0

CMD TRANSACTION ADDRESS / Special command

Field

CMD 7

TRANSACTION 6 : 5 W

ADDRESS

Special command

Bit

Type Description

W

4 : 0 W

Write 1

00 : COMMAND<4:0> is ADDRESS field. 01 : Reserved. 10 : Reserved. 11 : COMMAND<4:0> is Special command field.

Specify register address. Don’t specify invalid register address.

00001 : Interrupt output reset. 00010 : Stop manual integration mode. 00011 : Start manual integration mode. 00100 : Software reset Don’t input other commands.

Technical Note

default value 00h

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Rohm BH1730FVC Technical Note

Specifications and Main Features

Frequently Asked Questions

User Manual