Logic level shifting circuit
First Claim
1. A level shifting circuit for shifting a first voltage level to a second voltage level comprising an input port for inputting the first voltage level, an output port for outputting the second voltage level, a first inverter having an input and an output, a second inverter having an input and an output, the output of the first inverter being connected to the input of the second inverter, the input of the first inverter forming the input port and the output of the second inverter forming the output port, a voltage supply point via which the level shifting circuit is supplied with an operating voltage, and a leakage current limiting circuit connected in series between the first inverter and the voltage supply point for limiting a leakage current through the logic level shifting circuit.
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Accused Products
Abstract
A level shifting circuit (500) is provided for shifting a first voltage level to a second voltage level. The level shift is done by two inverters (542, 543) connected in cascade. The input of the first inverter forms the input port (501) of the level shifting circuit (500) where the first voltage level is input. The output of the second inverter forms the output port (502) of the level shifting circuit (500) where the second voltage level is output. The level shifting circuit (500) is operated by a single operating voltage (VDD). It further comprises a leakage current limiting circuit (541) connected in series between the first inverter (542) and the operating voltage (VDD) to limit a leakage current through the logic level shifting circuit (500). The level shifting circuit (500) is particularly suited to use in shifting logical 1 levels in mobile telephones.
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Citations
24 Claims
- 1. A level shifting circuit for shifting a first voltage level to a second voltage level comprising an input port for inputting the first voltage level, an output port for outputting the second voltage level, a first inverter having an input and an output, a second inverter having an input and an output, the output of the first inverter being connected to the input of the second inverter, the input of the first inverter forming the input port and the output of the second inverter forming the output port, a voltage supply point via which the level shifting circuit is supplied with an operating voltage, and a leakage current limiting circuit connected in series between the first inverter and the voltage supply point for limiting a leakage current through the logic level shifting circuit.
- 9. A digital logic circuitry comprising a plurality of subcircuits, each subcircuit using one of a plurality of voltage levels, a first voltage level of the plurality of voltage levels differing from a second voltage level of the plurality of voltage levels, a first subcircuit of the plurality of subcircuits being a level shifting circuit for shifting the first voltage level output from a second subcircuit of the plurality of subcircuits to the second voltage level for inputting to a third subcircuit of the plurality of subcircuits, the first subcircuit comprising an input port for inputting the first voltage level, an output port for outputting the second voltage level, a first inverter having an input and an output, a second inverter having an input and an output, the output of the first inverter being connected to the input of the second inverter, the input of the first inverter forming the input port and the output of the second inverter forming the output port, a voltage supply point via which the first subcircuit is supplied with an operating voltage, and a leakage current limiting circuit connected in series between the first inverter and the voltage supply point for limiting a leakage current through the first subcircuit.
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17. A mobile phone comprising a level shifting circuit for shifting a first voltage level, output from a first digital circuit, to a second voltage level for inputting to a second digital circuit, the level shifting circuit comprising an input port for inputting the first voltage level, an output port for outputting the second voltage level, a first inverter having an input and an output, a second inverter having an input and an output, the output of the first inverter being connected to the input of the second inverter, the input of the first inverter forming the input port and the output of the second inverter forming the output port, a voltage supply point via which the level shifting circuit is supplied with an operating voltage, and a leakage current limiting circuit connected in series between the first inverter and the voltage supply point for limiting a leakage current through the logic level shifting circuit.
Specification