 |
Electronic Components Datasheet Search |
|
|
Electronic Components Datasheet Search |
|
LM27966 Datasheet(PDF) 10 Page - National Semiconductor (TI) |
|
|
||||||||||||||||||||||||||||||
LM27966 Datasheet(HTML) 10 Page - National Semiconductor (TI) |
|
|
10 / 13 page  Circuit Description (Continued) Bit7 to Bit 5: Not Used DAUX1-DAUX0: Sets Brightness for DAUX pin. 11 = Fullscale Bit7 to Bit2:Not Used Full-Scale Current set externally by the following equation: IDx = 200 x 1.25V / RSET Brightness Level Control Table (Main Display) Brightness Code (hex) Analog Current (% of Full-Scale) Duty Cycle (%) Perceived Brightness Level (%) 00 20 1/16 1.25 01 20 2/16 2.5 02 20 3/16 3.75 03 20 4/16 5 04 20 5/16 6.25 05 20 6/16 7.5 06 20 7/16 8.75 07 20 8/16 10 08 20 9/16 11.25 09 20 10/16 12.5 0A 20 11/16 13.75 0B 20 12/16 15 0C 20 13/16 16.25 0D 20 14/16 17.5 0E 20 15/16 18.75 0F 20 16/16 20 10 40 10/16 25 11 40 11/16 27.5 12 40 12/16 30 13 40 13/16 32.5 14 40 14/16 35 15 40 15/16 37.5 16 40 16/16 40 17 70 11/16 48.125 18 70 12/16 52.5 19 70 13/16 56.875 1A 70 14/16 61.25 1B 70 15/16 65.625 1C 70 16/16 70 1D 100 13/16 81.25 1E 100 15/16 93.75 1F 100 16/16 100 D AUX Brightness Levels (%of Full-Scale) = 20%, 40%, 70%, 100% Application Information SETTING LED CURRENT The current through the LEDs connected to Dx can be set to a desired level simply by connecting an appropriately sized resistor (R SET) between the ISET pin of the LM27966 and GND. The Dx currents are proportional to the current that flows out of the I SET pin and are a factor of 200 times greater than the I SET current. The feedback loops of the internal amplifiers set the voltage of the I SET pin to 1.25V (typ.). The statements above are simplified in the equations below: I Dx=200x(VISET /RSET) R SET = 200 x (1.25V / IDx) Once the desired R SET value has been chosen, the LM27966 has the ability to internally dim the LEDs using a mix of Pulse Width Modulation (PWM) and analog current scaling. The PWM duty cycle is set through the I 2C compat- ible interface. LEDs connected to Main Display current sinks (Dx) can be dimmed to 32 different levels/duty-cycles. The internal PWM frequency for Main Display is a fixed 20kHz. D AUX has 4 analog current levels. Please refer to the I 2C Compatible Interface section of this datasheet for detailed instructions on how to adjust the brightness control registers. www.national.com 10 |
Similar Part No. - LM27966 |
|
Similar Description - LM27966 |
|
|
|
Link URL |
| Privacy Policy |
| ALLDATASHEET.COM |
| Does ALLDATASHEET help your business so far? [ DONATE ] |
About Alldatasheet | Advertisement | Datasheet Upload | Contact us | Privacy Policy | Link Exchange | Manufacturer List All Rights Reserved©Alldatasheet.com |
| Russian : Alldatasheetru.com | Korean : Alldatasheet.co.kr | Spanish : Alldatasheet.es | French : Alldatasheet.fr | Italian : Alldatasheetit.com Portuguese : Alldatasheetpt.com | Polish : Alldatasheet.pl | Vietnamese : Alldatasheet.vn Indian : Alldatasheet.in | Mexican : Alldatasheet.com.mx | British : Alldatasheet.co.uk | New Zealand : Alldatasheet.co.nz |
|
Family Site : ic2ic.com |
icmetro.com |
English ▼
English
Chinese
German
Japanese
Russian
Korean
Spanish
French
Italian
Portuguese
Polish
Vietnamese
Indian
Mexican
British
New Zealand
