HT1621B JSMICRO – reliable LCD controller for just €0.23!

HT1621B JSMICRO – versatile and reliable LCD driver A wealth of features for just €0.23!

The HT1621B in an SSOP48 package is a well-proven and popular LCD driver by Holtek, and its clone from JSMICRO with the same designation maintains full compatibility with the original Holtek device. This means it can be used in existing projects without any changes to the PCB or firmware — and at a much lower cost.

The driver is designed for simple and energy-efficient segment and alphanumeric displays. Flexible settings of voltage bias and duty cycles allow control of various display types, from basic 4-digit 7-segment modules to more advanced 32×4 matrices. The built-in 32×4-bit RAM stores the display image, while the HT1621B takes care of segment refreshing on its own, relieving the microcontroller and eliminating the need for LCD driving signals. Designers will also appreciate simple integration — communication is achieved through a 3-wire serial interface (CS, WR, DATA). The protocol distinguishes data from commands, and automatic address increment enables fast and convenient writing of consecutive display memory areas.

The HT1621B is equipped with several built-in clock generators. The 256 kHz RC oscillator eliminates the need for external resonators, while additional clock sources support both the time base and the watchdog timer. This makes the chip not only a display driver but also a simple system timer or microcontroller watchdog. Useful everyday features are included as well — the device can generate a basic audio signal at 2 kHz or 4 kHz for beeper support without additional components. The VLCD pin allows adjusting display voltage to provide optimal contrast under different supply conditions and for different LCD types.

The HT1621B relieves the microcontroller from all the burdens of LCD control — it stores the image in RAM, refreshes the display, and has its own clock and signal generation. All operating modes (bias and duty cycles, frequencies, reset, power-down mode) are set via software. No extra resistors or jumpers are needed, giving the user greater flexibility. By choosing the HT1621B from JSMICRO, you get 100% compatibility with Holtek, lower cost, easy microcontroller integration, and a range of additional features (oscillator, WDT, buzzer driver) that reduce overall project cost and simplify design.

Thanks to these advantages, the HT1621B JSMICRO is suitable for a wide range of applications — electronic scales, clocks, thermometers, household appliance control panels, medical devices and measurement systems. It is inexpensive, energy-efficient, reliable, and flexible enough to be used in virtually any project requiring LCD control.

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