National Semiconductor LM3530

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National Semiconductor LM3530

Description

The LM3530 current mode boost converter supplies the power and controls the current in up to 11 series white LED’s. The 839mA current limit and 2.7V to 5.5V input voltage range, makes the device a versatile backlight power source ideal for operation with Li+ batteries.

The LED current is adjustable from 0 to 29.5mA via an I 2C compatible interface. The 127 different current steps and 8 different maximum LED current levels give over 1000 programmable LED current levels. Additionally, PWM brightness control is possible through an external logic level input.

Additionally, the device features two Ambient Light Sensor inputs. These are designed to monitor analog output ambient light sensors and provide programmable adjustment of the LED current with changes in ambient light. Each ambient light sensor input has independently programmable internal voltage setting resistors which can be made high impedance to reduce power during shutdown. The LM3530's 500kHz switching frequency allows for high converter efficiency over a wide output voltage range accomodating from 2 to 11 series LEDs. Finally, the support of Content Adjusted Backlighting maximizes battery life while maintaining display image quality.

Datasheet: File:Lm3434.pdf