To fully understand the purpose of using a level shifter, let’s explain the meaning of a logic level. It is a number of possible signal’s states. It is usually indicated by the difference of voltage between the signal and the ground. The range of each voltage level can vary and it depends on the logic family used in a certain case.
Level shifter is a helpful tool to connect two different digital circuits with different logic levels. One level shifter provides connection from one circuit to another, in one direction. Because of that, when you want to achieve full connection in both directions, you have to use two level shifters. The operation of level shifter consists of converting digital signals from one to another logic level, usually from low to high voltage (such as MC14504B which converts TTL to CMOS, or MC10H607 that converts PECL to TTL).
A good practical example of level shifter application is a case when there are several devices that use different supply voltages, let’s say some of them use 3.3V signals and the others use 5V signals. Level shifter is a device that enables the production of voltage that can be used by the device operating with a higher voltage, while the circuit provides the lower voltage.
There are also other examples of level shifters such as I/O voltage level shifter integrated circuits (IC) that may consist of six digital voltage translator circuits. The input pins receive digital signals (VCC power pin) which are then converted into the voltage scale (VDD power pin) and after that they appear on the output.
Another kind of level shifters is represented by a bi-directional level shifter used for I2C-bus and other systems. Because of the fact that the level shifter is bi-directional, a single device can connect designs powered by different voltages. What’s more, it can separate the bus section of designs from the I2C bus.
Level shifter is a helpful tool to connect two different digital circuits with different logic levels. One level shifter provides connection from one circuit to another, in one direction. Because of that, when you want to achieve full connection in both directions, you have to use two level shifters. The operation of level shifter consists of converting digital signals from one to another logic level, usually from low to high voltage (such as MC14504B which converts TTL to CMOS, or MC10H607 that converts PECL to TTL).
A good practical example of level shifter application is a case when there are several devices that use different supply voltages, let’s say some of them use 3.3V signals and the others use 5V signals. Level shifter is a device that enables the production of voltage that can be used by the device operating with a higher voltage, while the circuit provides the lower voltage.
There are also other examples of level shifters such as I/O voltage level shifter integrated circuits (IC) that may consist of six digital voltage translator circuits. The input pins receive digital signals (VCC power pin) which are then converted into the voltage scale (VDD power pin) and after that they appear on the output.
Another kind of level shifters is represented by a bi-directional level shifter used for I2C-bus and other systems. Because of the fact that the level shifter is bi-directional, a single device can connect designs powered by different voltages. What’s more, it can separate the bus section of designs from the I2C bus.
