Circuit and method for converting a pair of input signals into a level-limited output signal
First Claim
1. A circuit that converts first and second input signals having first and second active levels, respectively, into an output signal, the circuit comprising:
- first and second input terminals operable to receive said first and second input signals;
an output terminal operable to provide said output signal;
first and second drive terminals;
a first stage that is coupled to said first input terminal, said first drive terminal, and said output terminal, said first stage operable to couple a first impedance between said first drive terminal and said output terminal when said first input signal is at said first active level, said first stage operable to reduce the magnitude of said first impedance for a first predetermined time after said first input signal transitions to said first active level; and
a second stage that is coupled to said second input terminal, said second drive terminal, and said output terminal, said second stage operable to couple a second impedance between said second drive terminal and said output terminal when said second input signal is at said second active level.
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Accused Products
Abstract
A circuit converts first and second input signals having first and second active levels, respectively, into an output signal. The circuit includes first and second input terminals, an output terminal and first and second drive terminals. A first stage of the circuit is coupled to the first input terminal, the first drive terminal and the output terminal. The first stage couples a first impedance between the first drive terminal and the output terminal when the first input signal is at the first active level, and reduces the magnitude of the first impedance for a first predetermined time after the first input signal transitions to the first active level. A second stage is coupled to the second input terminal, the second drive terminal and the output terminal, and couples a second impedance between the second drive terminal and the output terminal when the second input signal is at the second active level. The second stage may reduce the magnitude of the second impedance for a second predetermined time after the second input signal transitions to the second active level.
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Citations
28 Claims
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1. A circuit that converts first and second input signals having first and second active levels, respectively, into an output signal, the circuit comprising:
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first and second input terminals operable to receive said first and second input signals; an output terminal operable to provide said output signal; first and second drive terminals; a first stage that is coupled to said first input terminal, said first drive terminal, and said output terminal, said first stage operable to couple a first impedance between said first drive terminal and said output terminal when said first input signal is at said first active level, said first stage operable to reduce the magnitude of said first impedance for a first predetermined time after said first input signal transitions to said first active level; and a second stage that is coupled to said second input terminal, said second drive terminal, and said output terminal, said second stage operable to couple a second impedance between said second drive terminal and said output terminal when said second input signal is at said second active level. - View Dependent Claims (2)
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3. A circuit that converts first and second input signals having first and second active levels, respectively, into an output signal, the circuit comprising:
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first and second input terminals operable to receive said first and second input signals; an output terminal operable to provide said output signal; first and second supply terminals; a first stage that is coupled to said first input terminal, said first supply terminal, and said output terminal, said first stage operable to couple a first impedance between said first supply terminal and said output terminal when said first input signal is at said first active level, said first stage operable to reduce the magnitude of said first impedance for a first predetermined time after said first input signal transitions to said first active level; and a second stage that is coupled to said second input terminal, said second supply terminal, and said output terminal, said second stage operable to couple a second impedance between said second supply terminal and said output terminal when said second input signal is at said second active level, said second stage operable to reduce the magnitude of said second impedance for a second predetermined time after said second data signal transitions to said second active level. - View Dependent Claims (4)
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5. A circuit that converts first and second input signals having first and second active levels, respectively, into an output signal, the circuit comprising:
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first and second input terminals; an output terminal; first and second supply terminals; a first switch having a control terminal, a first switch terminal coupled to said first supply terminal, and a second switch terminal; a second switch having a control terminal coupled to said first input terminal, a first switch terminal coupled to said second switch terminal of said first switch, and a second switch terminal coupled to said output node; a third switch having a control terminal coupled to said second input terminal, a first switch terminal coupled to said output node, and a second switch terminal; a fourth switch having a control terminal, a first switch terminal coupled to said second switch terminal of said third switch, and a second switch terminal coupled to said second supply terminal; a first load coupled in parallel with said first switch; a second load coupled in parallel with said fourth switch; a first timer having an input terminal coupled to said first input terminal and having an output terminal coupled to said control terminal of said first switch, said first timer operable to activate said first switch for a first predetermined time after said first input signal transitions to said first active level; and a second timer having an input terminal coupled to said second input terminal and having an output terminal coupled to said control terminal of said fourth switch, said second timer operable to activate said fourth switch for a second predetermined time after said second input signal transitions to said second active level. - View Dependent Claims (6, 7, 8, 9)
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10. A circuit that converts first and second input signals into an output signal, the circuit comprising:
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first and second input terminals operable to receive said first and second input signals; an output terminal operable to provide said output signal; first and second supply terminals; a first switch having a control terminal, a first switch terminal coupled to said first supply terminal, and a second switch terminal coupled to said output terminal; a second switch having a control terminal coupled to said first input terminal, a first switch terminal coupled to said first supply terminal, and a second switch terminal; a third switch having a control terminal, a first switch terminal coupled to said output node, and a second switch terminal coupled to said second supply terminal; a fourth switch having a control terminal coupled to said second input terminal, a first switch terminal, and a second switch terminal coupled to said second supply terminal; a first load serially coupled between said second switch terminal of said second switch and said output terminal; a second load serially coupled between said first switch terminal of said fourth switch and said output terminal; a first timer having an input terminal coupled to said first input terminal and having an output terminal coupled to said control terminal of said first switch, said first timer operable to activate said first switch for a first predetermined time after said first input signal transitions to said first active level; and a second timer having an input terminal coupled to said second input terminal and having an output terminal coupled to said control terminal of said third switch, said second timer operable to activate said third switch for a second predetermined time after said second input signal transitions to said second active level. - View Dependent Claims (11, 12, 13)
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14. A memory device, comprising:
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first and second supply terminals; address, data, and command busses; a data pin coupled to said data bus; a bank of memory cells; an address decoder coupled to said address bus and said memory bank; a control circuit coupled to said command bus and to said address decoder; a read/write circuit coupled to said address decoder, control circuit, and memory bank, said read/write circuit operable to generate during a read cycle first and second data signals having first and second active levels respectively; and a data input/output circuit coupled to said data bus, read/write circuit, and control circuit, said data input/output circuit including a data output driver that includes, first and second input terminals coupled to said read/write circuit, an output terminal coupled to said data pin via said data bus, a first driver stage that is coupled to said first input terminal, said first supply terminal, and said output terminal, said first stage operable to couple a first impedance between said first supply terminal and said output terminal when said first data signal is at said first active level, said first stage operable to reduce the magnitude of said first impedance for a first predetermined time after said first data signal transitions to said first active level, and a second stage that is coupled to said second input terminal, said second supply terminal, and said output terminal, said second stage operable to couple a second impedance between said second supply terminal and said output terminal when said second data signal is at said second active level, said second stage operable to reduce the magnitude of said second impedance for a second predetermined time after said second data signal transitions to said second active level. - View Dependent Claims (15, 16, 17, 18, 19, 20, 21)
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22. A computer system, comprising:
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a data input device; a data output device; and computing circuitry coupled to said data input and output devices, said computing circuitry including a memory device that includes, first and second supply terminals, address, data, and command busses, a data pin coupled to said data bus, a bank of memory cells, an address decoder coupled to said address bus and said memory bank, a control circuit coupled to said command bus and to said address decoder, a read/write circuit coupled to said address decoder, control circuit, and memory bank, said read/write circuit operable to generate during a read cycle first and second data signals having first and second active levels respectively, and a data input/output circuit coupled to said data bus, read/write circuit, and control circuit, said data input/output circuit including a data output driver that includes, first and second input terminals coupled to said read/write circuit, an output terminal coupled to said data pin via said data bus, a first driver stage that is coupled to said first input terminal, said first supply terminal, and said output terminal, said first stage operable to couple a first impedance between said first supply terminal and said output terminal when said first data signal is at said first active level, said first stage operable to reduce the magnitude of said first impedance for a first predetermined time after said first data signal transitions to said first active level, and a second stage that is coupled to said second input terminal, said second supply terminal, and said output terminal, said second stage operable to couple a second impedance between said second supply terminal and said output terminal when said second data signal is at said second active level, said second stage operable to reduce the magnitude of said second impedance for a second predetermined time after said second data signal transitions to said second active level. - View Dependent Claims (23, 24)
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25. A method for driving a node with an output signal, comprising:
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receiving a first input signal having a first active level; receiving a second input signal having a second active level; coupling a first drive signal to said node through a first impedance when said first input signal is at said first active level; coupling a second drive signal to said node through a second impedance when said second input signal is at said second active level; and increasing the magnitude of said second impedance at a first predetermined time after said second input signal attains said second active level. - View Dependent Claims (26, 27, 28)
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Specification