Dual-Mode Level Shifting Circuit for Ground Disturbance Stability
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Solution Overview
Problem
Existing level shifters face malfunctions due to ground voltage disturbances when operating with low voltage devices, particularly when the ground voltage fluctuates, leading to incorrect signal conversions between different power domains in IC chips.
Innovation Solution
The level shifting circuit incorporates a first-type level shifter without a bias circuit and a second-type level shifter with a bias circuit, along with a controller to enable or disable the bias circuit based on the mode signal, ensuring normal operation by controlling the bias voltage supply.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a level shifter operates with low voltage devices without a bias circuit, then power consumption is reduced, but the level shifter malfunctions when ground voltage fluctuates
Solution Approach 1:
The patent implements a dynamic bias circuit that can be enabled or disabled based on operating conditions. The bias circuit is turned off during normal operation to save power and turned on when ground voltage fluctuation is detected to prevent malfunction, creating a dynamic adaptation between power consumption and reliability
Solution Approach 2:
The patent changes the electrical parameter (bias voltage) of the level shifter based on detected ground voltage conditions. When ground voltage fluctuation is detected, the bias voltage is applied to stabilize the level shifter's operation, otherwise it remains unset to minimize power consumption
2Reliability
If a bias circuit is always enabled in the level shifter, then signal conversion stability is improved, but power consumption increases
Solution Approach 1:
The patent uses periodic monitoring of ground voltage to determine when the bias circuit should be activated. Instead of continuous operation, the system periodically checks ground voltage conditions and enables the bias circuit only when fluctuations are detected, creating an on-demand operation pattern
Solution Approach 2:
The detection circuit automatically monitors ground voltage and controls the bias circuit activation without external intervention. The system serves itself by detecting its own operating conditions and adjusting the bias circuit state accordingly, eliminating the need for manual control
3Device complexity
If the level shifter is designed without a bias circuit, then device complexity is reduced, but the level shifter becomes sensitive to ground voltage disturbances
Solution Approach 1:
The patent divides the level shifter into separate functional modules: a detection circuit that monitors ground voltage and a bias circuit that is activated only when needed. This segmentation allows the main level shifter to remain simple while adding protection only when necessary
Solution Approach 2:
The detection circuit acts as an intermediary between the ground voltage and the bias circuit. It monitors ground voltage conditions and mediates the activation of the bias circuit, protecting the simple level shifter structure from ground voltage disturbances without requiring the level shifter itself to be complex
Data Source
AI summary
A level shifting circuit includes a first-type level shifter, a second-type level shifter and a controller. The controller is connected to the output terminal of the first-type level shifter and the output terminal of the second-type level shifter. The level shifting circuit can be operated in different modes. In a standby mode, the logic level state of an output signal from the level shifting circuit is determined according to the logic level state of a shifted signal from the first-type level shifter. In a non-standby mode, the logic level state of the output signal from the level shifting circuit is determined according to the logic level state of a shifted signal from the second-type level shifter.