IT1503 - PWM-Embedded 3x4-Channel Constant- Current Sink Driver


IT1503 is a 3×4-channel, constant-current, PWM embedded sink driver for LED strips. The constant current ranges from 3mA to 45mA for each output channel and are adjustable with three related external resistors. The power system can support both 3.3V and 5V and output channel can sustain up to 17V. With error detection, IT1503 can detect individual LED for both open- and short-circuit errors without extra components. Besides, with the random PWM spreading on-time technology, IT1503 increases functional refresh rate at the same grey scale quality. The grey scale clock (GCLK) can be generated by the internal oscillator or from the external clock source.

IT1503 provides two optional grey scale modes to trade off between image quality and transmission: 16-bit grey scale mode and 10-bit grey scale mode. The 16-bit grey scale mode provides 65,536 grey scales for each LED to enrich the color. Subject to the 16-bit grey scale mode, the 8-bit dot correction may adjust each LED by 256-step gain th compensate the LED brightness. Furthermore, the 10-bit grey scale mode provides 1,024 grey scales. Subject to the 10-bit grey scale mode, 6-bit dot correction may adjust each LED by 64-step gain.

In addition, IT1503 features a two-wire transmission interface to make cluster-to-cluster connection easier. To improve the transmission quality, IT1503 provides phase-inversed output clock to eliminate the accumulation of signal pulse width distortion. IT1503 is also flexible for either manual-synchronization or auto-synchronization. The manual-synchronization is to maintain the synchronization of image frames between ICs. The auto-synchronization is to achieve accurate grey scale, especially when using the built-in oscillator.



  • Constant current range: 3~45mA

  • Supply voltage: 3V~5.5V

  • Voltage at output channels: 17V (max.)

  • 3 clusters of output current; each cluster’s current is set by an external resistor

  • Embedded 16-bit PWM generator

  • - Grey scale clock can be generated by the internal oscillator or from the external clock

  • Two optional modes for image quality and transmission bandwidth selection

  • - 10-bit grey scale mode (with optional 6-bit dot correction)

    - 16-bit grey scale mode (with optional 8-bit dot correction)

  • Flexible PWM reset modes

  • - Auto- synchronization mode

    - Manual-compliant mode

  • Reliable data transmission interface

  • - Daisy-chain flow

    - Built-in buffer for long distance driving

    - Two-wire signals for interface

    - Output clock phase inversed

  • Error detection control

  • - Compulsory individual LED open/short-circuit detection:

     full panel, data independent

     silent error detection in 700ns

    - Configurable short-circuit detection threshold voltage

  • RoHS-compliant packages



Technology Information:

  Data Sheet

  Package: SSOP-24



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