Clock Input Buffer Wake-Up Control for LPDDR2 Power Saving
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Solution Overview
Problem
Clock input buffers in low power double data rate 2 (LPDDR2) memory circuits consume power even when the clock is stable due to their implementation with differential amplifiers, leading to inefficiencies in power management.
Innovation Solution
An enable circuit is implemented to power down the clock input buffer during stable clock conditions and quickly enable it upon clock toggling, utilizing a clock detector and SR latch to manage power consumption by disabling and re-enabling the buffer based on clock activity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the clock input buffer is implemented with a differential amplifier to ensure stable clock signal processing, then the clock signal stability is improved, but the power consumption increases even when the clock is stable
Solution Approach 1:
The patent implements dynamic control of the clock input buffer by transitioning it between enabled and disabled states based on clock activity detection. The buffer is enabled during clock transitions and disabled during stable periods, making the power consumption adaptive rather than static. This resolves the contradiction by maintaining signal stability when needed while reducing power consumption during stable periods.
Solution Approach 2:
The system uses the clock signal itself to control the power state of the clock input buffer through automatic detection of clock transitions. The buffer automatically enables itself when detecting clock activity and disables itself during stable periods, eliminating the need for external control signals and achieving self-managed power optimization while maintaining functionality.
2Speed
If the clock input buffer is continuously enabled to ensure immediate response to clock transitions, then the response speed is improved, but the power consumption increases during stable clock periods
Solution Approach 1:
The patent implements preliminary action by detecting clock transitions in advance and enabling the clock input buffer just before they become critical. The transition detector monitors the clock signal and proactively activates the buffer when transitions are detected, ensuring the buffer is ready to process signals without requiring continuous operation. This maintains response speed while enabling power savings during stable periods.
Solution Approach 2:
The system employs periodic action by enabling the clock input buffer only during periods when clock transitions are detected rather than continuously. The buffer operates in a periodic manner - enabled during active transition periods and disabled during stable periods - which maintains necessary response capability while significantly reducing overall power consumption compared to continuous operation.
3Use of energy by moving object
If the clock input buffer is disabled during stable clock conditions to reduce power consumption, then the power efficiency is improved, but the delay in re-enabling the buffer upon clock toggling increases
Solution Approach 1:
The patent implements feedback by using a transition detector that continuously monitors the clock signal and provides real-time information about clock transitions. This feedback mechanism immediately detects when the clock transitions from stable to active state and triggers the re-enabling of the clock input buffer without delay. The feedback loop ensures that the buffer is re-enabled precisely when needed, minimizing re-enable delay while maintaining power efficiency during stable periods.
Solution Approach 2:
The system uses an intermediary transition detector circuit that sits between the clock signal source and the clock input buffer. This intermediary component monitors clock transitions and controls the enabling/disabling of the buffer, acting as a mediator that coordinates between power management requirements and signal processing needs. The intermediary enables rapid response to clock transitions while allowing the buffer to remain disabled during stable periods, thus reducing both power consumption and re-enable delay.
Data Source
AI summary
An integrated circuit may have a clock input pin coupled to a buffer (24). The buffer may supply a clock signal (28) to an integrated circuit chip such as the memory. To conserve power, the buffer is powered down. When ready for use, the buffer is quickly powered back up. In one embodiment, in response to a predetermined number of toggles Of the clock signal, the buffer is automatically powered up.