 |
Electronic Components Datasheet Search |
|
|
Electronic Components Datasheet Search |
|
ADP5501 Datasheet(PDF) 9 Page - Analog Devices |
|
|
|||||||||||||||||||||||||||||
ADP5501 Datasheet(HTML) 9 Page - Analog Devices |
|
|
9 / 28 page  ADP5501 Rev. 0 | Page 9 of 28 THEORY OF OPERATION 1 PGND 21 VBAT 16 VDDIO 5 SCL 4 SDA 3 INT 15 RST ADP5501 4.7µH 1µF 1µF 1µF 2.7V TO 5.5V 6 NC 7 NC 8 NC 9 NC 10 NC 11 NC 2 SW 22 BST BL_SNK 20 CAP_OUT 100nF 17 CMP_IN 14 LED0 12 LED1 13 LED2 STATE MACHINE REGISTER MAP INTERRUPT/RESET CONTROL INTERFACE BIAS/CLOCK LIGHT SENSOR LED CURRENT CONTROL POR LDO IN EN OUT 2.7V 23 THERMAL PROTECTION BACKLIGHT CURRENT CONTROL BOOST CONTROL 0.65V FB OVP I-LIMIT 27V VBAT 18 GND 19 GND 24 GND Figure 13. Internal Block Diagram The ADP5501 is an autonomous backlight white LED driver with programmable current and ambient light sensor input. It is ideal for cellular phone designs and other portable devices, where programmable and automated light output is needed. Its versatility makes it ideal for media-enabled mobile devices. Programmable fade-in, fade-out, dim, and off timers provide the backlight with excellent flexibility and control features. Using an external photodiode, the ADP5501 can perform ambient light sensing and adjust the backlight brightness according to varying lighting conditions. Programmable fading is also available for the three LED sinks. Once programmed through its I2C-compatible interface, the ADP5501 can run autonomously. An interrupt line (INT) is available to alert an external microprocessor of the status of its ambient light sensor comparator states, current limit, thermal overload, and overvoltage conditions. BACKLIGHT DRIVE CONTROL White LEDs are common in backlighting the displays of modern portable devices such as cell phones. White LEDs require a high forward voltage, VF (typically, 3.5 V), before they conduct current and emit light. Display panels, depending on their size, can be backlit with single or multiple white LEDs. In panels that require multiple LEDs, the LEDs are commonly connected in a series string to achieve uniform brightness in each LED by passing a common current through all of them. The LED string, however, needs to be biased with a voltage greater than the sum of each LED VF before it can conduct. To achieve this high voltage, the ADP5501 contains a nonsyn- chronous boost device capable of driving an LED string with an OVP limited to 24.5 V(minimum). For detailed information about the boost device, see the Applications Information section. With sufficient forward voltage created, the ADP5501 controls the current (and thus the brightness) of the LED string via an adjustable internal current sink. An internal state machine, in conjunction with programmable timers, dynamically adjusts the current sink between 0 mA and 30 mA to achieve impressive backlight control features. BST DARK_MAX DAYLIGHT_MAX DAYLIGHT_DIM OFFICE_MAX OFFICE_DIM BL_VALUE MUX DARK_DIM COUNTERS AND CONTROL LOGIC BL_DIMT BL_FI BL_FO BL_EN DIM_EN BL_OFFT BL_LAW CLOCK GENERATOR BL_LVL BL_SNK Figure 14. Backlight Brightness Control |
|
Link URL |
| Does ALLDATASHEET help your business so far? [ DONATE ] |
About Alldatasheet | Advertisement | Contact us | Privacy Policy | Link to Datasheet | 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
