Browse Prior Art Database

Level Shifter for both low and high voltage levels shifting

IP.com Disclosure Number: IPCOM000240128D
Publication Date: 2015-Jan-05
Document File: 4 page(s) / 334K

Publishing Venue

The IP.com Prior Art Database

Abstract

A Level Shifter typically transfers a signal when only one voltage level is different, e.g. conversion from vdd1 to vdd2 levels having the same general ground level or conversion from gnd1 to gnd2 levels having the same power voltage level. This paper describes an area, power and timing effective structure of level shifter which allows shifting both power voltage and ground voltage levels. New structure of level shifter includes Ground shift unit, which provides ground voltage level shifting, Power voltage shift unit, which provides power voltage level shifting and “Cross-coupled” block, consisting of nmos- or pmos-transistors, depending on implementation, which is shared between Ground shift and Power voltage shift units.

This text was extracted from a Microsoft Word document.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 53% of the total text.

Level Shifter for both low and high voltage levels shifting

Abstract

A Level Shifter typically transfers a signal when only one voltage level is different, e.g. conversion from vdd1 to vdd2 levels having the same general ground level or conversion from gnd1 to gnd2 levels having the same power voltage level. This paper describes an area, power and timing effective structure of level shifter which allows shifting both power voltage and ground voltage levels. New structure of level shifter includes Ground shift unit, which provides ground voltage level shifting, Power voltage shift unit, which provides power voltage level shifting and “Cross-coupled” block, consisting of nmos- or pmos-transistors, depending on implementation, which is shared between Ground shift and Power voltage shift units.

Introduction

Currently System-on-Chips (SoCs) can include several power and ground domains to reduce total power and these domains can have both biased power voltage level as well as biased ground level. So to transfer a signal from biased domain (when both power and ground voltages are biased) to unbiased domain (when both power and ground voltages are un-biased) a special level shifter is required, which allows to shift both power voltage and ground voltage levels.

Figure 1. Signal transfer from biased domain to un-biased domain

An example of signal transfer from biased domain to un-biased domain is shown in Figure 1. In this example vdd1_biased is less than vdd2_unbiased and gnd1_biased is greater than gnd2_unbiased. Other combinations of power voltage and ground levels are also possible: Vdd1 ≥ Vdd2 and Vgnd1 ≤ Vgnd2.

To transfer a signal from biased domain (when both power and ground voltages are biased) to unbiased domain (when both power and ground voltages are un-biased) a special level shifter, which allows shifting both power voltage and ground voltage levels, has been developed.

Block diagram of a new level shifter

New structure of level shifter consists of:

- Ground shift unit, which provides ground voltage level shifting;

- Power voltage shift unit, which provides power voltage level shifting;

- “Cross-coupled” block consisting of nmos- or pmos-transistors, depending on implementation, which is shared between Ground shift and Power voltage shift units. It allo...