| 摘要 |
A method and circuitry (5) for enhancing the reproducibility and reliability of circuitry for reading a memory array (10a, 10b, 10a', 10b') provides a dynamically generated reference voltage for the sensing circuitry. The invention senses the highest word line voltage and communicates a voltage derived therefrom to the sensing circuitry (26, 27, 28, 29; 26', 27', 28', 29'; 32, 33) to provide a reference voltage. A voltage clamp (62) is coupled to the circuitry for communicating the highest word line voltage (50) to prevent the reference voltge from following the word line too low during transitions. The invention is rendered compatible with the existing write circuitry associated with the memory array (10a, 10b, 10a', 10b') by the provision of disabling circuitry (65) coupled to the communicating circuitry (55, 57) and to the clamp (62). The disabling circuitry (65) is responsive to a write control signal and operates to prevent the high word line voltage from being communicated to the sensing circuitry, and further operates to allow the communication of lower voltage than would normally be permitted by the clamp (62).
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