Single supply level converter
First Claim
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1. A level converter for interfacing circuits supplied by different supply voltages, said level converter comprising:
- a first buffer receiving an input, said first buffer being connected between a virtual supply and a supply return;
a second buffer receiving an output of said first buffer, connected between a first supply and said supply return; and
a supply select between said first supply and said virtual supply, said supply select receiving an output from said second buffer and selectively passing a first supply voltage on said first supply or a reduced supply voltage to said virtual supply responsive to said output from said second buffer, wherein at least two circuits interfaced by said level converter are in the same integrated circuit (IC) as said level converter.
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Abstract
A level converter for interfacing two circuits supplied by different supply voltages, and integrated circuit including the level converter interfacing circuit in two different voltage islands. A first buffer is supplied by a virtual supply and receives an input signal from a lower voltage circuit. The first buffer drives a second buffer, which is supplied by a higher supply voltage. An output from the second buffer switches a supply select to selectively pass the higher supply voltage or a reduced supply voltage to the first buffer.
15 Citations
19 Claims
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1. A level converter for interfacing circuits supplied by different supply voltages, said level converter comprising:
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a first buffer receiving an input, said first buffer being connected between a virtual supply and a supply return; a second buffer receiving an output of said first buffer, connected between a first supply and said supply return; and a supply select between said first supply and said virtual supply, said supply select receiving an output from said second buffer and selectively passing a first supply voltage on said first supply or a reduced supply voltage to said virtual supply responsive to said output from said second buffer, wherein at least two circuits interfaced by said level converter are in the same integrated circuit (IC) as said level converter. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 19)
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12. A voltage level converter circuit comprising:
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a first inverter with a first inverter input connected to an output of a first circuit on the same integrated circuit (IC) as said first inverter, a first inverter output, a first inverter ground connected to a circuit ground, and a first inverter voltage supply; a threshold drop element connected between a circuit high voltage supply (Vddh) and the first inverter voltage supply; a second inverter with a second inverter input connected to the first inverter output, a second inverter output connected to an input of a second circuit on the same integrated circuit (IC) as said second inverter, a second inverter ground connected to the circuit ground, and a second inverter voltage supply connected to Vddh; and a voltage feedback element connected between Vddh and the first inverter voltage supply, the voltage feedback element having an input connected to the second inverter output, wherein when the second inverter output is low, the voltage feedback element causes the first inverter voltage supply to approach Vddh and making the first inverter output approach Vddh thereby eliminating a standby power in the second inverter, and wherein at least two circuits interfaced by said level converter are in the same integrated circuit (IC) as said level converter. - View Dependent Claims (13, 14, 15, 16, 17, 18)
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Specification