Ambient Light Sensor IC Series Digital 16bit Serial Output ...

1 Ambient Light Sensor IC Series Digital 16bit Serial Output Type Ambient Light Sensor IC. BH1750 FVI Descriptions 2. BH1750 FVI is an Digital Ambient Light Sensor IC for I C bus interface. This IC is the most suitable to obtain the Ambient Light data for adjusting LCD and Keypad backlight power of Mobile phone. It is possible to detect wide range at High resolution. ( 1 - 65535 lx ). Features 2. 1) I C bus Interface ( f / s Mode Support ). 2) Spectral responsibility is approximately human eye response 3) Illuminance to Digital Converter 4) Wide range and High resolution. ( 1 - 65535 lx ). 5) Low Current by power down function 6) 50Hz / 60Hz Light noise reject-function 7) Logic input interface 8) No need any external parts 9) Light source dependency is little. ( ex. Incandescent Lamp. Fluorescent Lamp. Halogen Lamp. White LED.

2 Sun Light ). 10) It is possible to select 2 type of I2C slave-address. 11) Adjustable measurement result for influence of optical window ( It is possible to detect min. lx, max. 100000 lx by using this function. ). 12) Small measurement variation (+/- 20%). 13) The influence of infrared is very small. Applications Mobile phone, LCD TV, NOTE PC, Portable game machine, Digital camera, Digital video camera, PDA, LCD display Absolute Maximum Ratings Parameter Symbol Ratings Units Supply Voltage Vmax V. Operating Temperature Topr -40 85 . Storage Temperature Tstg -40 100 . SDA Sink Current Imax 7 mA. Power Dissipation Pd 260 mW. 70mm 70mm glass epoxy board. Derating in done at for operating above Ta=25 . Operating Conditions Ratings Parameter Symbol Units Min. Typ. Max. VCC Voltage Vcc V. I2C Reference Voltage VDVI - VCC V. 1/17 - 2011 ROHM Co.

3 , Ltd. All rights reserved. BH1750 FVI Technical Note Electrical Characteristics ( VCC = , DVI = , Ta = 25 , unless otherwise noted ). Limits Parameter Symbol Units Conditions Min. Typ. Max. 1. Supply Current Icc1 120 190 A Ev = 100 lx Powerdown Current Icc2 A No input Light Peak Wave Length p 560 nm Sensor out / Actual lx Measurement Accuracy S/A times EV = 1000 lx 1, 2. 3. Dark ( 0 lx ) Sensor out S0 0 0 3 count H-Resolution Mode H-Resolution Mode Resolution rHR 1 lx L-Resolution Mode Resolution rLR 4 lx H-Resolution Mode tHR 120 180 ms Measurement Time L-Resolution Mode tLR 16 24 ms Measurement Time Incandescent /. rIF 1 times EV = 1000 lx Fluorescent Sensor out ratio ADDR Input H' Voltage VAH * VCC V. ADDR Input L' Voltage VAL * VCC V. DVI Input L' Voltage VDVL V. SCL, SDA Input H' Voltage 1 VIH1 * DVI V DVI SCL, SDA Input H' Voltage 2 VIH2 V DVI SCL, SDA Input L' Voltage 1 VIL1 * DVI V DVI SCL, SDA Input L' Voltage 2 VIL2 DVI V DVI SCL, SDA, ADDR.

4 IIH 10 A. Input H' Current SCL, SDA, ADDR. IIL 10 A. Input L' Current I2C SCL Clock Frequency fSCL 400 kHz 2. I C Bus Free Time tBUF s 2. I C Hold Time ( repeated ). tHDSTA s START Condition I2C Set up time tSUSTA s for a Repeated START Condition I2C Set up time tSUSTD s for a Repeated STOP Condition I2C Data Hold Time tHDDAT 0 s I2C Data Setup Time tSUDAT 100 ns I2C L' Period of the SCL Clock tLOW s I2C H' Period of the SCL Clock tHIGH s I2C SDA Output L' Voltage VOL 0 V IOL = 3 mA. 1 White LED is used as optical source. 2 Measurement Accuracy typical value is possible to change '1' by "Measurement result adjustment function". 3 Use H-resolution mode or H-resolution mode2 if dark data ( less than 10 lx ) is need. 2/17 - 2011 ROHM Co., Ltd. All rights reserved. BH1750 FVI Technical Note Reference Data 64 100000. 56. 1. 10000.

5 48. Measurement Result Measurement Result 40. 1000. 32. Ratio H-Res. H-Res. L-Res. 24 100. 16. 10. 8 L-Res. 0 1. 0 0 8 16 24 32 40 48 56 64 1 10 100 1000 10000 100000. 400 500 600 700 800 900 1000 1100. Illuminance [ lx ] Illuminance [ lx ]. Wavelength [ nm ]. Spectral Response Illuminance - Illuminance - Measurement Result 1 Measuremnet Result 2. 10. 1. 1. 8 . 1pin Measurement Result - +. 6. Ratio - Ratio 1pin - 4. - +. + 2. + H-Res. 0. 0 -90 -60 -30 0 30 60 90 0. -90 -60 -30 0 30 60 90 -40 -20 0 20 40 60 80 100. Angle [ deg ] Angle [ deg ]. Ta [ ]. Directional Characteristics 1 Directional Characteristics 2 Dark Response 200. Fluorescent Light 1. Incandescent ICC @ Measurement 150. Light Halogen Light Ratio 100. Kripton Light Artifical Sun 50. Light White LED. 0 0. -40 -20 0 20 40 60 80 100 0 1 2 2 3 4. Ta [ ] Ratio VCC [ V ].

6 Measurement Accuracy Light Source Dependency VCC - ICC. Temperature Dependency ( Fluorescent Light is set to '1' ) ( During measurement ). 10. ICC @ POWER DOWN [ uA ]. 1 1. DVI= VCC=3V. 1. Ratio Ratio 0 0. -40 -20 0 20 40 60 80 100. 2 3 4 2 3 Ta [ ] VCC [ V ] DVI [ V ]. VCC ICC@0 Lx Measurement Result Measurement Result ( POWER DOWN ) VCC Dependency DVI Dependency 3/17 - 2011 ROHM Co., Ltd. All rights reserved. BH1750 FVI Technical Note Block Diagram VCC DVI. Logic SCL. AMP ADC +. 2. I C Interface SDA. PD. OSC. GND ADDR. Block Diagram Descriptions PD. Photo diode with approximately human eye response. AMP. Integration-OPAMP for converting from PD current to Voltage. ADC. AD converter for obtainment Digital 16bit data. 2. Logic + I C Interface Ambient Light Calculation and I2C BUS Interface. It is including below register.

7 Data Register This is for registration of Ambient Light Data. Initial Value is "0000_0000_0000_0000". Measurement Time Register This is for registration of measurement time. Initial Value is "0100_0101". OSC. Internal Oscillator ( typ. 320kHz ). It is CLK for internal logic. Measurement Procedure Power supply Initial state is Power Down mode after State is automatically changed to VCC and DVI supply. Power Down mode. Power Down Power On Measurement Command One Time Measurement Continuous Measurement State Transition by I2C write-command. Automatically State Transition * "Power On" Command is possible to omit. 4/17 - 2011 ROHM Co., Ltd. All rights reserved. BH1750 FVI Technical Note Instruction Set Architecture Instruction Opecode Comments Power Down 0000_0000 No active state. Power On 0000_0001 Waiting for measurement command.

8 Reset Data register value. Reset command is not acceptable in Reset 0000_0111. Power Down mode. Start measurement at 1lx resolution. Continuously H-Resolution Mode 0001_0000. Measurement Time is typically 120ms. Start measurement at resolution. Continuously H-Resolution Mode2 0001_0001. Measurement Time is typically 120ms. Start measurement at 4lx resolution. Continuously L-Resolution Mode 0001_0011. Measurement Time is typically 16ms. Start measurement at 1lx resolution. One Time H-Resolution Mode 0010_0000 Measurement Time is typically 120ms. It is automatically set to Power Down mode after measurement. Start measurement at resolution. One Time H-Resolution Mode2 0010_0001 Measurement Time is typically 120ms. It is automatically set to Power Down mode after measurement. Start measurement at 4lx resolution. One Time L-Resolution Mode 0010_0011 Measurement Time is typically 16ms.

9 It is automatically set to Power Down mode after measurement. Change Measurement time Change measurement time. 01000_MT[7,6,5]. ( High bit ) Please refer "adjust measurement result for influence of optical window.". Change Masurement time Change measurement time. 011_MT[4,3,2,1,0]. ( Low bit ) Please refer "adjust measurement result for influence of optical window.". Don't input the other opecode. Measurement mode explanation Measurement Mode Measurement Time. Resolurtion H-resolution Mode2 Typ. 120ms. lx H-Resolution Mode Typ. 120ms. 1 lx. L-Resolution Mode Typ. 16ms. 4 lx. We recommend to use H-Resolution Mode. Measurement time ( integration time ) of H-Resolution Mode is so long that some kind of noise( including in 50Hz / 60Hz noise ) is rejected. And H-Resolution Mode is 1 l x resolution so that it is suitable for darkness ( less than 10 lx ).

10 H-resolution mode2 is also suitable to detect for darkness. Explanation of Asynchronous reset and Reset command "0000_0111". 1) Asynchronous reset All registers are reset. It is necessary on power supply sequence. Please refer "Timing chart for VCC and DVI power supply sequence" in this page. It is power down mode during DVI = 'L'. 2) Reset command Reset command is for only reset Illuminance data register. ( reset value is '0' ) It is not necessary even power supply is used for removing previous measurement result. This command is not working in power down mode, so that please set the power on mode before input this command. 5/17 - 2011 ROHM Co., Ltd. All rights reserved. BH1750 FVI Technical Note Timing chart for VCC and DVI power supply sequence DVI is I2C bus reference voltage terminal. And it is also asynchronous reset terminal.