EVAL.BH1721FVC

Ambient Light Sensor IC Series Digital 16bit Serial Output Type Ambient Light Sensor IC BH1721FVC No.11046ECT10 ●Descriptions 2 BH1721FVC 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 - 65528 lx ). ●Features 2 1) I C bus Interface ( f / s Mode Support, Slave Address : "0100011" ) 2) Spectral responsibility is approximately human eye response 3) Illuminance to Digital Converter 4) Wide range and High resolution. (1 – 65528 lx ) 5) Low Current by power down function 6) 50Hz / 60Hz Light noise reject-function 7) 1.8V Logic input interface 8) No need any external parts 9) Light source dependency is little. (ex. Incandescent Lamp. Fluorescent Lamp. Halogen Lamp. White LED. Sun Light) 10) Small measurement variation (+/- 15%) 11) Compact surface mount package 1.6 x 1.6 x 0.55 mm ●Applications Mobile phone, LCD TV, NOTE PC, Portable game machine, Digital camera, Digital video camera, PDA, LCD display ●Absolute Maximum Ratings Parameter Supply Voltage Symbol Limits Units Vmax 4.5 V Operating Temperature Topr -40～85 ℃ Storage Temperature Tstg -40～100 ℃ SDA Sink Current Imax 7 mA Power Dissipation Pd 165※ mW ※70mm × 70mm × 1.6mm glass epoxy board. Derating in done at 2.2mW/℃ for operating above Ta=25℃. ●Operating Conditions Parameter VCC Voltage 2 I C Reference Voltage www.rohm.com © 2011 ROHM Co., Ltd. All rights reserved. Symbol Min. Typ. Max. Units Vcc 2.4 3.0 3.6 V VDVI 1.65 - VCC V 1/15 2019. 9 - Rev.C Technical Note BH1721FVC ●Electrical Characteristics ( VCC = 3.0V, DVI = 3.0V, Ta = 25℃, unless otherwise noted ) Parameter Units Conditions Symbol Min. Typ. Max. Supply Current Icc1 － 140 199 µA Ev = 100 lx Powerdown Current Icc2 － 0.01 1.0 µA No input Light Peak Wave Length λp － 560 － nm Measurement Accuracy S/A 1.02 1.2 1.38 times Dark ( 0 lx ) Sensor out S0 0 0 2 H-Resolution Mode Resolution rHR － 1 － lx L-Resolution Mode Resolution rLR － 8 － lx H-Resolution Mode Measurement Time tHR － 120 180 ms L-Resolution Mode Measurement Time tLR － 16 24 ms Incandescent / Fluorescent Sensor out ratio rIF － 1 － DVI Input ‘L’ Voltage VDVL － － 0.4 V SCL, SDA Input ‘H’ Voltage 1 VIH1 0.7 * DVI － － V DVI ≧ 1.8V 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, Input ‘H’ Current IIH － － 10 µA SCL, SDA, Input ‘L’ Current IIL － － 10 µA 2 fSCL － － 400 kHz 2 tBUF 1.3 － － µs 2 tHDSTA 0.6 － － µs 2 tSUSTA 0.6 － － µs 2 tSUSTO 0.6 － － µs 2 tHDDAT 0 － － µs 2 tVDDAT － － 0.9 µs 2 tVDACK － － 0.9 µs 2 tSUDAT 100 － － ns 2 tLOW 1.3 － － µs 2 tHIGH 0.6 － － µs 2 VOL 0 － 0.4 V I C SCL Clock Frequency I C Bus Free Time I C Hold Time ( repeated ) START Condition I C Set up time for a Repeated START Condition I C Set up time for a Repeated STOP Condition I C Data Hold Time I C Data Valid Time I C Data Valid Acknowledge Time I C Data Setup Time I C ‘L’ Period of the SCL Clock I C ‘H’ Period of the SCL Clock I C SDA Output ‘L’ Voltage ※1 Sensor out / Actual lx 1, 2 EV = 1000 lx ※ ※ count H-Resolution Mode ※3 times EV = 1000 lx 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 if dark data ( less than 20 lx ) is need. www.rohm.com © 2011 ROHM Co., Ltd. All rights reserved. 2/15 2019. 9 - Rev.C Technical Note BH1721FVC ●Reference Data 100000 64 1.2 56 Ratio 0.8 0.6 0.4 10000 48 Measurement Result Measurement Result 1.0 40 32 H-Res. 24 16 L-Res. 0.2 1000 100 10 8 0.0 400 500 600 700 800 900 1000 0 1100 0 8 16 Wavelength [ nm ] 24 32 40 48 56 1 64 1 Illuminance [ lx ] 10 100 1000 10000 100000 Illuminance [ lx ] Fig.2 Illuminance Measurement Result 1 Fig.1 Spectral Response 1.2 Fig.3 Illuminance Measuremnet Result 2 1.2 1 10 1 8 - 0.8 + + Ratio Ratio 0.8 0.6 - 0.6 1pin 0.4 Measurement Result 1pin 0.4 - + 0.2 6 4 + 0.2 2 H-Res. + 0 0 -90 -60 -30 0 30 60 0 90 -90 -60 -30 Angle [ deg ] 0 30 60 90 -40 -20 0 Fig.4 Directional Characteristics 1 20 40 60 80 100 Ta [ ℃ ] Angle [ deg ] Fig.6 Dark Response Fig.5 Directional Characteristics 2 200 1.2 Fluorescent Light 1 ICC @ Measurement Incandescent Light 0.8 Ratio Halogen Light 0.6 Kripton Light 0.4 Artifical Sun Light 0.2 150 100 50 White LED 0 0 -40 -20 0 20 40 60 80 100 0 Ta [ ℃ ] 1 1.5 2 2 2.5 Ratio 10 1.2 VCC=3V 0.8 Ratio Ratio 0.8 0.6 0.2 0.2 0 0 -40 -20 0 20 40 60 80 100 Ta [ ℃ ] Fig.10 VCC – ICC@0 lx (POWER DOWN) www.rohm.com © 2011 ROHM Co., Ltd. All rights reserved. 0.6 0.4 0.4 0.01 4 1 DVI=1.8V 0.1 3.5 1.2 1 1 3 VCC [ V ] Fig.9 VCC – ICC (During measurement) Fig.8 Light Source Dependency (Fluorescent Light is set to ‘1’) Fig.7 Measurement Result Temperature Dependency ICC @ POWER DOWN [ uA ] 0.5 2 2.5 3 3.5 VCC [ V ] Fig.11 Measurement Result VCC Dependency 3/15 4 1.5 2 2.5 3 3.5 DVI [ V ] Fig.12 Measurement Result DVI Dependency 2019. 9 - Rev.C Technical Note BH1721FVC ●Block Diagram DVI VCC AMP ADC Logic + I C Interface SCL 2 SDA PD OSC GND ●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 2 Ambient Light Calculation and I C BUS Interface. It is including below register. 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 "01_0010_1100". ・OSC Internal Oscillator. It is CLK for internal logic. ●Measurement Procedure Power supply Initial state is Power Down mode after VCC and DVI supply. Power Down Power On Measurement command 2 State Transition by I C write-command. Automatically State Transition Continuous measurement * www.rohm.com © 2011 ROHM Co., Ltd. All rights reserved. 4/15 "Power On" Command is possible to omit. 2019. 9 - Rev.C Technical Note BH1721FVC ●Instruction Set Architecture Instruction Opecode Comments Power Down 0000_0000 No active state. Power On 0000_0001 Waiting for measurement command. Continuously Auto-Resolution Mode 0001_0000 0010_0000 Switch measurement mode automatically by illuminance. Continuously H-Resolution Mode 0001_0010 0010_0010 Start measurement at 1lx resolution. Measurement Time is typically 120ms. Continuously L-Resolution Mode 0001_0011 0001_0110 0010_0011 0010_0110 Start measurement at 8lx resolution. Measurement Time is typically 16ms. Change Measurement time ( High bit ) 010_MT[9,8,7,6,5] Change Masurement time ( Low bit ) 011_MT[4]_XXXX Change measurement time. ※ Please refer "adjust measurement result for influence of optical window." Change measurement time. ※ Please refer "adjust measurement result for influence of optical window." ※ Don't input the other opecode. ●Measurement mode explanation Measurement Mode Measurement Time. H-Resolution Mode L-Resolution Mode Measurement Range. Resolution Typ. 120ms 0 - 8191 lx 1 lx Typ. 16ms 0 - 65528 lx 8 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 lx resolution so that it is suitable for darkness (less than 20 lx) Auto-Resolution mode selects measurement mode automatically. It is determined after 16ms (typ.) passes from measurement start. If BH1721FVC judges that current illuminance is more than 4000 lx, then Data is output at L-resolution mode, else Data is output after 120ms(typ.) from measurement start at H-resolution mode. Please refer below flow chart. Start after 16ms.(typ.) Select mode Lux 4000 DATA output at L-resolution mode Data output at H-resolution mode after 120ms passes from measurement start. Auto-Resolution mode measurement www.rohm.com © 2011 ROHM Co., Ltd. All rights reserved. 5/15 2019. 9 - Rev.C Technical Note BH1721FVC ●Timing chart for VCC and DVI power supply sequence 2 DVI is I C bus reference voltage terminal. And it is also asynchronous reset terminal. It is necessary to set to ‘L’ after VCC is supplied. In DVI 'L' term, internal state is set to Power Down mode. 1) Recommended Timing chart1 for VCC and DVI supply. VCC DVI Reset Term (more than 1µs) 2) Timing chart2 for VCC and DVI supply. (If DVI rises within 1µs after VCC supply) VCC DVI Reset Term (more than 1µs) Don't care state www.rohm.com © 2011 ROHM Co., Ltd. All rights reserved. 6/15 2019. 9 - Rev.C Technical Note BH1721FVC ●Measurement sequence example from "Write instruction" to "Read measurement result" ex1) Continuously Auto-resolution mode from Slave to Master from Master to Slave ① Send "Continuously Auto-resolution mode " instruction ST 0100011 ② Wait to complete 1st 0 Ack 00010000 Ack SP Auto-resolution mode measurement.( max. 180ms ) ③ Read measurement result. ST 0100011 1 Ack Low Byte [ 7:0 ] High Byte [ 15:8 ] Ack Ack SP How to calculate when the data High Byte is "10000011" and Low Byte is "10010000" 15 9 8 7 4 ( 2 + 2 + 2 + 2 + 2 ) / 1.2 ≒ 28067 [ lx ] The result of continuously measurement mode is updated. ex2) Continuously L-resolution mode ① Send " Continuously L-resolution mode " instruction ST 0100011 0 Ack 00010011 Ack SP ② Wait to complete L-resolution mode measurement.( max. 24ms ) ③ Read measurement result ST 0100011 1 Ack Low Byte [ 7:0 ] High Byte [ 15:8 ] Ack Ack SP How to calculate when the data High Byte is "00000001" and Low Byte is "00010000" 8 4 ( 2 + 2 ) / 1.2 ≒ 227 [ lx ] www.rohm.com © 2011 ROHM Co., Ltd. All rights reserved. 7/15 2019. 9 - Rev.C Technical Note BH1721FVC ●Application circuit example of DVI terminal The DVI terminal is an asynchronous reset terminal. Please note that there is a possibility that IC doesn't operate normally if the reset section is not installed after the start-up of VCC. (Please refer to the paragraph of "Timing chart for VCC and DVI power supply sequence”) The description concerning SDA and the terminal SCL is omitted in this application circuit example. Please design the 2 application the standard of the I C bus as it finishes being satisfactory. ex 1) The control signal line such as CPU is connected. BH1721FVC VCC SCL Micro Controller 0.1µF GND SDA 0.1µF DVI 0.1µF ex 2) Reset IC is used. 1, For Reset IC of the Push-Pull type BH1721FVC VCC SCL 0.1µF RESET GND SDA 0.1µF DVI Reset IC( Push-Pull type ) 0.1µF 2, For Reset IC of the Open drain output BH1721FVC VCC SCL 0.1µF 1kΩ RESET GND SDA 0.1µF DVI Reset IC( Open drain type ) 0.1µF ex 3) A different power supply is used. BH1721FVC VCC SCL 0.1µF V1 GND 0.1µF SDA DVI V2 0.1µF ※ Power supply of DVI must stand up later than power supply of VCC stand up, because it is necessary to secure reset section ( 1µs or more ). www.rohm.com © 2011 ROHM Co., Ltd. All rights reserved. 8/15 2019. 9 - Rev.C Technical Note BH1721FVC ex 4) LPF using CR is inserted between VCC and DVI. This method has the possibility that the Reset section of turning on the power supply can not satisfied. Cannot be satisfied. Please design the set considering the characteristic of the power supply enough. R1 : 1kΩ BH1721FVC VCC SCL 0.1µF GND 0.1µF SDA DVI C1 : 1µF ◆ Notes when CR is inserted between VCC and DVI ※Please note that there is a possibility that reset section ( 1µs ) can not be satisfied because the power supply is turned on when the rise time of VCC is slow ※When VCC is turned off, the DVI voltage becomes higher than VCC voltage but IC destruction is not occred if recommended constant ( R1 = 1kΩ, C1 = 1µF ) is used. ※Please note that there is a possibility that Reset section (1µsec) cannot be satisfied if wait time is not enough long after turning off VCC. (It is necessary to consider DVI voltage level after turning off VCC.) t1 VCC t2 DVI 2.4V 0.4V 0V Reset Section: 1µs or more * Please do the application design to secure Reset section 1µs or more after the reclosing of the power supply. ◆ Example of designing set when CR ( C = 1µF, R = 1kΩ ) is inserted between VCC and DVI with VCC=2.8V ①The rise time to 0→2.4V of VCC must use the power supply of 100µs or less. ②Please wait 25ms or more after VCC turn off ( VCC