Digital tube driver and keyboard control chip: CH455


Overview

The CH455 is a digital tube display driver and a keyboard scan control chip. The CH455 has a built-in clock oscillating circuit that can dynamically drive a 4-bit digital tube or 32 LEDs. It can also perform a 28-key keyboard scan. The CH455 exchanges data with a microcontroller via a 2-wire serial interface consisting of SCL and SDA.

Features

  • Built-in display current drive stage, segment current is not less than 25mA, word current is not less than 160mA.
  • Dynamic display scan control, support 8 × 4 or 7 × 4, direct drive 4-digit digital tube or 32 LED.
  • Internal current limit, providing 8 levels of brightness control through duty cycle setting.
  • Built-in 28-key keyboard controller based on 7×4 matrix keyboard scan.
  • Built-in debounce circuit with pull-down resistor for built-in button status input.
  • Provides an active low keyboard interrupt and provides a button release flag for querying and releasing the button.
  • High-speed 2-wire serial interface with clock speeds from 0 to 4MHz, compatible with two-wire I2C bus, saving pins.
  • Built-in power-on reset, support 2.7V ~ 5V power supply voltage.
  • Supports low-power sleep, saves power, can be woken up by a button or wake up by a command operation.
  • Built-in clock oscillating circuit, no need to provide external clock or external oscillating components, more anti-interference.
  • Available in DIP18, SOP18 and SOP16 lead-free packages, RoHS compliant, functional and pin compatible with CH450 chips.