Dynamic Clock-Gated Command Decoder for LPDDR5 Power Reduction
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Solution Overview
Problem
Conventional command decoder circuits in LPDDR5 SDRAMs experience high power consumption due to the constant switching of the system clock signal between high and low levels during decoding of activate commands.
Innovation Solution
A command decoder circuit comprising a first decoder unit, a second decoder unit, and a clock gate that generates a dynamic clock signal based on a chip select signal, allowing the dynamic clock signal to be active only during decoding of the first and second activate commands, thereby reducing power consumption by avoiding unnecessary switching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the system clock signal constantly switches between high and low levels during decoding, then the decoding operation can be performed continuously, but the power consumption increases significantly
Solution Approach 1:
The clock signal is transformed from continuous switching to periodic/pulsed switching. The clock gate generates clock pulses only during specific periods when decoding is actually needed (when chip select signal is active), rather than constantly switching. This periodic action maintains decoding productivity while significantly reducing power consumption by eliminating unnecessary clock transitions during idle periods.
Solution Approach 2:
The clock signal characteristics are made dynamic rather than static. The clock gate dynamically adjusts the clock signal based on the chip select signal state, generating clock pulses only when decoding operations are required. This dynamic approach allows the system to adapt clock activity to actual workload, maintaining productivity when needed while reducing power consumption during idle periods.
2Ease of operation
If the clock signal switches constantly to maintain decoding readiness, then decoding can be performed immediately when needed, but energy is wasted during idle periods
Solution Approach 1:
The system prepares for decoding by monitoring the chip select signal in advance. When the chip select signal becomes active, the clock gate is ready to immediately generate clock pulses without delay. This preliminary preparation maintains decoding readiness while avoiding continuous clock switching during idle periods, thus reducing energy waste while ensuring quick response when decoding is needed.
3Use of energy by moving object
If the clock gate generates dynamic clock signal only during active decoding periods, then power consumption is reduced, but the timing control becomes more complex
Solution Approach 1:
The clock gate serves as an intermediary component between the chip select signal and the decoding units. It receives the chip select signal and translates it into appropriately timed clock pulses for the decoding units. This intermediary approach simplifies the overall timing control by centralizing the clock generation logic in a single component rather than distributing complex timing control across multiple units, thus reducing overall system complexity while maintaining reduced power consumption.
Data Source
AI summary
A command decoder circuit, a memory, and an electronic device are provided. The circuit includes a first decoder unit, configured to perform decoding for a first command signal based on a dynamic clock signal; a second decoder unit, configured to perform decoding for a second command signal based on the dynamic clock signal; and the clock gate, configured to generate the dynamic clock signal after a chip select signal of the first decoder unit indicates that decoding to be started for the first command signal and before the second decoder unit has performed decoding for the second command signal, and cut off the dynamic clock signal before the chip select signal of the first decoder unit indicates that the decoding to be started for the first command signal or after the second decoder unit has performed decoding for the second command signal.