Level shifter and level shifter circuit

Abstract

A driving circuit provides a symmetric differential driving signal relative to one set of voltage potentials to a driver circuit that drives an output node to another set of voltage potentials. The differential driving signals from the driving system are equal and opposite to each other, thereby avoiding stray current flow between the driving system and the driven current mirrors. The transistors that provide the driving signal are continuously biased, using a weak bias in one logic state and stronger bias in the other state, to avoid hard-switching transients.

Description

technical field [0001] The present invention relates to the field of electronic circuits, and more particularly to a level shifter with independent ground potential and reduced electromagnetic emissions (EME). Background technique [0002] Level shifters are commonly used to provide communication of signals from one system having a first voltage potential range to another system having a different voltage potential range. For example, level shifters are commonly used in automotive applications because typical automotive systems operate on 0-18 volts, while typical integrated circuits typically operate on 0-3 volts, or 0-5 volts. A 3 or 5 volt output from an integrated circuit asserted as a "logic high" is not strong enough to be interpreted as a logic high in a 12 volt system. Level shifters provide proper mapping of voltage levels from one system to another to ensure correct communication of logic values. [0003] Figure 1 illustrates the principle of a conventional level...

AI Technical Summary

Problems solved by technology

However, the output transistors P2 and N2 are hard driven to each corresponding rail voltage V+ and V-, causing substantial electromagnetic emissions (EME) on every transition of the bus state

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