Logic level converter

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Papan logic level converter sering diperlukan jika bekerja dengan dua atau lebih sistem yang mempergunakan tingkat tegangan yang berbeda. Sistem yang bekerja di tingkat tegangan 3.3 V dan tidak memiliki toleransi tegangan sampai 5 V akan sangat mungkin mengalami kerusakan. Untuk mencegahnya diperlukan sistem yang mengalihkan level logika digital dari sistem 5 V dari dan ke level 3.3 V.

Penggunaan sistemnya cukup sederhana, yang penting untuk diingat adalah bahwa sumber tegangan di kedua sisi perlu dihubungkan. Jika misalnya sisi 3.3 V tidak memiliki catau daya sendiri maka pergunakan sumber lain dengan tegangan yang sama sebesar 3.3 V. Contohnya dari papan Arduino, hubungkan 5 V dan 3.3 V ke pin masing-masing yang sesuai. Adapun pin Gnd sudah terhubung antar sisi, sehingga level yang dikonversi diukur berdasarkan acuan yang sama. Jadi, Gnd untuk sistem (termasuk untuk ground sisi 3.3 V) bisa didapatkan hanya dari satu hubungan ke GND pada papan Arduino.

 

Do you have a 3.3V I2C or SPI sensor that might go up in smoke if connected to a 5V Arduino? Or a 5V device that needs a workaround to be compatible with your 3.3V Raspberry Pi, Arduino Due or pcDuino?

To get over this obstacle you need a device that can shift 3.3V up to 5V or 5V down to 3.3V. This is called logic level shifting. Level shifting is a dilemma so common we designed a simple PCB assembly to make interfacing devices a little easier: the Bi-Directional Logic Level Converter.

MOSFET logic level shifting circuitGambar 1.

Annotated BD-LLCGambar 2.

 

~learn.sparkfun.com

 

I2c-Bi-Directional-021Gambar 3. [14core.com]

 

As digital devices get smaller and faster, once ubiquitous 5 V logic has given way to ever lower-voltage standards like 3.3 V, 2.5 V, and even 1.8 V, leading to an ecosystem of components that need a little help talking to each other. For example, a 5 V part might fail to read a 3.3 V signal as high, and a 3.3 V part might be damaged by a 5 V signal. This level shifter solves these problems by offering bidirectional voltage translation of up to four independent signals, converting between logic levels as low as 1.5 V on the lower-voltage side and as high as 18 V on the higher-voltage side, and its compact size and breadboard-compatible pin spacing make it easy to integrate into projects.

Gambar 4.

This logic level converter requires two supply voltages: the lower-voltage logic supply (1.5 V to 7 V) connects to the LV pin and the higher-voltage supply (LV to 18 V) connects to the HV pin. The HV supply must be higher than the LV supply for proper operation. Logic low voltages will pass directly from Hx to the corresponding Lx (and vice versa), while logic high voltages will be converted between the HV level to the LV level as the signal passes from Hx to Lx or Lx to Hx.

~www.pololu.com/product/2595

 

 

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