Method and apparatus for high speed comparison
AssigneeInternational Business Machines Corporation
InventorsKevin Xiaoqiang Zhang, George McNeil Lattimore, Terry Lee Leasure
Life of this patent
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Abstract
According to the present invention, a comparison circuit for combining a plurality of data bits is provided. One version of the invention includes a comparator which provides a signal responsive to a comparison of the voltage states of at least two of the plurality of data bits, and an amplifier which is coupled to the comparator and compares the signal provided by the comparator to a reference voltage to provide an output signal, the reference voltage being between a high and a low voltage state.
Claims20
A comparison circuit for comparing a plurality of data bits, each data bit being in either a high or a low voltage state, the comparison circuit comprising:
- a comparator which provides a signal responsive to a comparison of the voltage states of at least two of the plurality of data bits;
- an amplifier which is coupled to the comparator and compares the signal provided by the comparator to a reference voltage to provide an output signal, the reference voltage being between a high and a low voltage state, and an evaluation signal generator comprising an inverter having an input coupled to a precharge transistor the input having a conditional discharge path responsive to the voltage level of at least one of the plurality of data bits.
A comparison circuit for comparing a plurality of data bits, each data bit being in either a high or a low voltage state, the comparison circuit comprising:
- a comparator having a first input responsive to the voltage state of a first data bit, a second input responsive to the voltage state of a second data bit, and an output which provides a signal having a voltage level responsive to a comparison of the voltage state of the first and second data bits;
- an amplifier having a first input coupled to the output of the comparator, a second input coupled to a reference voltage, and an output which provides a signal responsive to a comparison of the voltage level of the output of the comparator and the reference voltage, and
- an evaluation signal generator which provides a conditional discharge path for the reference voltage, the evaluation signal generator being responsive to the voltage level of at least one of the plurality of data bits.
A method for comparing data bits in a digital circuit, each data bit having either a high or a low voltage level, the method comprising:
- precharging an output of a comparison circuit to a high voltage level;
- providing first and second bits to the comparison circuit;
- coupling the output of the comparison circuit to ground if the voltage level of the first bit is different than the voltage level of the second bit;
- comparing the voltage level of the output of the comparison circuit to a reference voltage which is between the high voltage level and the low voltage level, the comparison comprising:
- providing the voltage level of the output of the comparison circuit to a first input of a sense amplifier:
- providing the reference voltage to a second input of the sense amplifier:
- providing an evaluation signal to create a conditional discharge path for the reference voltage, the evaluation signal being responsive to the voltage level of at least one of the data bits;
- providing an output signal responsive to the comparison.
Dependencies are inferred from the claim text.