Level-Converting Enable Latch for Cross-Domain Data Retention
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Solution Overview
Problem
There is a need for a latch design that can efficiently transfer data between different power domains, specifically from a power down domain to an always-on domain, while managing voltage swings and enabling/disabling latch feedback loops to conserve power.
Innovation Solution
The proposed solution involves a level converting enable latch that includes a level shifter circuit and a latch circuit, utilizing transistors and footer transistors for voltage conversion and latch control, allowing data transfer and enabling/disabling latch feedback loops based on logic values of the latch enable signal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If data is transferred between different power domains with different voltage swings, then data transfer capability is improved, but voltage level mismatch causes operational failure
Solution Approach 1:
A level shifter circuit is introduced as an intermediary component between the first logic circuit (power down domain) and the second logic circuit (always-on domain). The level shifter converts voltage swings from a first voltage level (e.g., 1.8V) to a second voltage level (e.g., 1.2V), enabling reliable data transfer across power domains with different voltage characteristics without direct connection between the logic circuits
2Reliability
If the latch feedback loop is always enabled to maintain data, then data integrity is improved, but power consumption increases
Solution Approach 1:
The latch feedback loop is designed to be dynamically controllable through a latch enable signal. The feedback loop is enabled when data transfer is needed and disabled when data is stable, allowing the circuit to adapt its operational state. This dynamic control mechanism reduces power consumption by eliminating continuous feedback when data integrity is already maintained, while ensuring data integrity is preserved when the feedback loop is active
Data Source
AI summary
A level converting enable latch includes a level shifter circuit and a latch circuit. The level shifter circuit receives a first data input signal, and generates a first data output signal, wherein the first data input signal and the first data output signal have different voltage swings. The latch circuit sets a second data output signal in response to the first data output signal when a latch enable signal is set to a first logic value, and latches the second data output signal when the latch enable signal is set to a second logic value. The latch circuit includes a first control circuit. The first control circuit enables a latch feedback loop of the latch circuit when the latch enable signal is set to the second logic value, and disables the latch feedback loop of the latch circuit when the latch enable signal is set to the first logic value.