16-digit digital tube driver and keyboard control chip: CH456


Overview

The CH456 is a 16-bit digital tube display driver and keyboard scan control chip. The CH456 has a built-in clock oscillating circuit that can dynamically drive up to 16 digital tubes or 128 LED tubes; it can also perform 64-key keyboard scanning; CH456 exchanges data with a single-chip microcomputer through a 2-wire serial interface. The figure below shows the application block diagram of CH456.

Features

  • Built-in display current drive stage, segment current is not less than 25mA, word current is not less than 150mA.
  • Dynamic display scan control, directly driving 16 digital tubes or 128 LEDs.
  • Internal current limit, multi-level brightness control is provided by duty cycle setting.
  • Built-in 64-key keyboard controller based on 8×8 matrix keyboard scan.
  • Active low-level keyboard interrupt, a button release flag is provided for querying the button to be pressed and released.
  • Some of the unused display driver pins X12 to X15 can be used as GPO general purpose output pins.
  • High-speed 2-wire serial interface with clock speeds from 0 to 2MHz, compatible with two-wire I2C bus, saving pins.
  • Built-in clock oscillating circuit, no need to provide external clock or external oscillating components, more anti-interference.
  • Support 3V, 3.3V, 5V power supply voltage.
  • Supports low-power sleep, saves power, can be woken up by a button or wake up by a command operation.
  • Available in four lead-free packages, DIP20, SOP20, DIP16 and SOP16, RoHS compliant.