AS1122-BQFT ams

AS1122 12-Channel LED Driver with Dot Correction and Greyscale PWM The AS1122 is a 12-channel, constant current-sink LED driver. General Description Each of the 12 channels can be individually adjusted by 4096-step greyscale PWM brightness control and 64-step constant-current sink (dot correction). The dot correction circuitry adjusts the brightness variations between the AS1122 channels and other LED drivers. Greyscale control and dot correction circuitry are accessible via a simple SPI-compatible serial interface. The open LED detection function indicates a broken or disconnected LED at one or more of the outputs. The overtemperature flag indicates that the device is in an overtemperature condition. A single external resistor sets the maximum current value of all 12 channels. The AS1122 is available in a 24-pin QFN 4 4mm package. Ordering Information and Content Guide appear at end of datasheet. Key Benefits & Features The benefits and features of the AS1122, 12-Channel LED Driver with Dot Correction and Greyscale PWM, are listed below: Figure 1: Added Value of Using AS1122 Benefits Features High resolution LED brightness control 12-bit (4096 steps) Greyscale PWM Control Independent fine tuning of LED current of each 6-bit (64 steps) Dot Correction channel to adjust brightness deviation Suitable for high-power LEDs Drive capability up to 40mA Multiple white LEDs in series per channel LED Power Supply up to 30V Inrush current control Delayed enabling of each output channel Applications The device is ideal for mono-color, multi-color, and full-color LED displays, LED signboards, and display backlights. ams Datasheet Page 1 v1-02 2015-May-22 Document FeedbackAS11 22 Gene ral Des c rip t ion Block Diagram The functional blocks of this device for reference are shown below: Figure 2: Functional Blocks of AS1122 SDI CLKO Identifier Control 2.7V to 3.6V VDD CIN Greyscale 12-Bit PWM Constant Current Register Control Driver GS Input Dot Correction 6-Bit Dot OUT0..3 Delay 0 Shift Register Correction OUT0..3 CLKI Register Command Register Control IRQ Control Greyscale 12-Bit PWM Constant Current Logic Register Control Driver CLK DC RST Counter OUT4..7 Input Dot Correction 6-Bit Dot Delay 1 Shift Register Correction OUT4..7 Register IREF MAX OUTn Command Current Register Control PWM Greyscale 12-Bit PWM Constant Current Control Counter Register Control Driver Comm Input Dot Correction 6-Bit Dot OUT8..11 Delay 2 Shift Register Correction OUT8..11 Register Command Register GND SDO Page 2 ams Datasheet Document Feedback v1-02 2015-May-22