Digital tube driver and keyboard control chip CH451


The CH451 is a versatile peripheral chip that integrates digital tube display driver and keyboard scan control with μP monitoring.CH451 has built-in RC oscillator circuit, which can dynamically drive 8-digit digital tube or 64 LED tube, with BCD decoding, flickering, shifting, etc. It can also perform 64-key keyboard scanning; The CH451 exchanges data with a single chip microcomputer via a serial interface that can be cascaded; it also provides monitoring functions such as power-on reset and watchdog.


2.1. Display driver

  • Built-in high current drive stage, segment current is not less than 25mA, word current is not less than 150mA.
  • Dynamic display scan control, direct drive 8-digit digital tube or 64 LED Luminous tubes.
  • The segment of the digital tube and data bit can be chosen as no decoding mode or BCD decoding mode.
  • Left shift, right shift, left loop, right loop of the digital tube word data.
  • Each digital tube is digitally flashed independently.
  • Arbitrary segment addressing, independently controlling the on and off of each LED or each segment of each digital tube.
  • 16 levels of brightness control are provided by the duty cycle setting.
  • The segment current upper limit adjustment is supported, and the limited current resistance can be omitted.
  • Scanning limit control, supports 1 to 8 digital tubes, and only allocates scan time for valid digital tubes.

2.2. keyboard control

  • Built-in 64-key keyboard controller based on 8×8 matrix keyboard scan.
  • Built-in debounce circuit with pull-down resistor for built-in button status input.
  • Keyboard interrupt, active low output.
  • A button release flag is provided for querying the button to be pressed and released.

2.3. Others

  • High-speed 4-wire serial interface that supports multi-chip cascading with clock speeds from 0 to 10MHz.
  • The DIN and DCLK signal lines in the serial interface can be shared with other interface circuits, saving pins.
  • Fully built-in clock oscillating circuit, no need for external crystal or RC oscillation.
  • Built-in power-on reset and watchdog Watch-Dog and provide active-high and active-low reset outputs.
  • Supports low-power sleep, saves power, can be woken up by a button or wake up by a command operation.
  • Support 3V~5V voltage.
  • Available in SOP28 and DIP24S lead-free packages, compatible with RoHS
  • The pin and function are basically compatible with the CH452 chip of the 4-wire interface mode.

relation files

file name file content
CH452DS1.PDF CH452 datasheet. CH452 can be used for 64 LEDs or 8×8 segment digital tube drive and 64-key keyboard scanning control, simplifying the workload of MCU.
CH450DS1.PDF CH450 datasheet. CH450 is used for driver of 48 LEDs or 6 digital tubes and for 48-key keyboard scan control, compatible with high-speed two-wire interface.
CH454DS1.PDF CH454 datasheet. CH454 is used for display driver of 16-segment LED displays or 8 alphanumeric displays and for keyboard scan control, supports 17 segments x 7 digital tubes, 16 segments x 8 digital tubes and 8 segments x 16 digital tubes.
CH456DS1.PDF CH456 datasheet. CH456 is used for 16 digital tubes display drive and 64-key keyboard scanning. CH456 supports 2-wire serial interface, and is compatible with IIC, simplifying the workload of MCU.
CH423DS1.PDF CH423 datasheet. A remote I/O expander with 2-wire serial interface, used for 16 digital tube display or I/O expansion applications through two wires. The input terminal is a two-wire interface compatible with I2C, and the output terminal is an 8-bit bidirectional input/output port and a 16-bit high-current output port.
CH453DS1.PDF CH453 datasheet. CH453 can be used for 128 LEDs or 16×8 segment digital tube drive and 64-key keyboard scanning control.
CH463DS1.PDF CH463 datasheet, LCD display driver chip, 16 × 8 or 12 × 4 and other LCD display driver and 35-key keyboard scanning control, support for LCD backlight 64-level adjustment, 2-wire interface, compatible with I2C.