I/O Circuit Impedance Code Selection Across Power Supply Modes
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Solution Overview
Problem
Conventional semiconductor memory peripheral circuits face challenges in adjusting impedance around input/output terminals effectively, particularly when dealing with different peripheral power supply voltages, which affects data input/output drivers and increases power consumption.
Innovation Solution
The implementation of a ZQ code selector that provides different impedance codes to pull-up and pull-down drivers of data input/output circuits, as well as on-die termination drivers of command/address and clock input circuits, based on impedance calibration, allowing for adjustable impedance settings according to varying power supply modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a common impedance code is provided to all input/output circuits, then the circuit complexity is reduced, but the impedance adjustment precision deteriorates because it cannot accommodate different peripheral power supply voltages
Solution Approach 1:
The patent divides the input/output circuits into multiple groups based on their peripheral power supply voltage requirements. Each group is assigned a dedicated impedance code, allowing precise impedance adjustment for each group while maintaining manageable overall system complexity through systematic organization.
Solution Approach 2:
Different impedance codes are assigned to different input/output circuit groups according to their specific power supply voltage conditions. This ensures that each circuit group receives the optimal impedance setting tailored to its local operating conditions, improving overall impedance adjustment precision.
2Manufacturing precision
If impedance is adjusted for each input/output circuit according to different power supply voltages, then the impedance adjustment precision is improved, but the device complexity increases
Solution Approach 1:
The patent creates a universal impedance control framework where a single impedance control circuit can serve multiple input/output circuit groups by selecting appropriate impedance codes based on power supply voltage conditions. This multi-functional approach achieves precise impedance adjustment without proportionally increasing device complexity.
Solution Approach 2:
The impedance codes are dynamically selected based on the actual power supply voltage conditions of each input/output circuit group. This dynamic adaptation allows the system to achieve precise impedance adjustment for varying operating conditions without requiring separate fixed impedance control circuits for each group.
3Speed
If power supply voltages are increased for high-speed operations, then the memory access speed is improved, but the power consumption increases
Solution Approach 1:
The patent dynamically adjusts the impedance codes based on the current power supply voltage conditions. When high voltage is applied for high-speed operations, the impedance is optimized to minimize signal reflection and maximize data reliability. When low voltage is used for power saving, the impedance is adjusted accordingly. This dynamic impedance matching ensures optimal performance across different power consumption modes without requiring continuous high voltage operation.
Data Source
AI summary
Apparatuses including an impedance code selector are disclosed. An example apparatus according to the disclosure includes an impedance calibration circuit, an impedance code selector and a driver circuit in a data input/output circuit. The impedance calibration circuit provides a first impedance code. The impedance code selector provides either the first impedance code or a second impedance code. The driver circuit receives either the first impedance code or the second impedance code from the impedance code selector.