Nonvolatile Memory Plane Control for Read Optimization

The patent applies local quality by configuring different read reference voltages for different planes based on their program states. Specifically, planes that have undergone MSB programming use a first read reference voltage, while planes that have undergone LSB programming use a second read reference voltage. This localized differentiation of read parameters ensures accurate data retrieval from each plane without being affected by the program state differences of other planes, thereby resolving the contradiction between simultaneous read speed and read accuracy.

The patent implements preliminary action by determining the program state of each plane (MSB or LSB) before performing read operations. The controller pre-configures the appropriate read reference voltage for each plane based on its program state, and this configuration is maintained throughout the read operation. This advance preparation eliminates the need for complex dynamic adjustments during reading, simplifying the control logic while ensuring accurate reads from planes with different program states.

The patent applies partial action by enabling only the necessary number of planes for read operations based on the actual data access requirements. Instead of uniformly enabling all planes, the controller selectively activates planes that require reading, determined by their program states and the read command parameters. This selective activation reduces the number of simultaneously operating planes, thereby lowering energy consumption while maintaining the required read throughput for the actual data being accessed.