Level-Shifting Circuit Clamping for Leakage Current Control
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Solution Overview
Problem
Conventional level-shifting circuits experience undesirable leakage currents, particularly when operating with high or low supply voltages, which can lead to inefficiencies and errors in signal conversion.
Innovation Solution
The proposed level-shifting circuit incorporates a clamping circuit and feedback circuit to limit leakage current by maintaining the PMOS transistor in an OFF state and using a clamping circuit with a Schottky barrier diode and native NMOS transistor to restrict current flow, effectively reducing leakage to nanoampere levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional level-shifting circuit is used to convert voltage levels, then voltage level conversion is achieved, but leakage current increases
Solution Approach 1:
The patent introduces a clamping circuit as an intermediary component between the inverter and ground. This clamping circuit, comprising a clamping transistor and clamping resistor, acts as a mediator to control and limit the leakage current path without interfering with the primary voltage level conversion function of the inverter.
Solution Approach 2:
The patent modifies the electrical parameters of the circuit by adding the clamping circuit that dynamically adjusts the resistance and current flow characteristics. The clamping transistor changes its conduction state based on voltage levels, thereby dynamically controlling the leakage current parameter while maintaining signal integrity.
2Adaptability or versatility
If high-supply voltage is applied to shift voltage levels, then voltage level conversion capability is improved, but leakage current in the circuit increases
Solution Approach 1:
The clamping circuit serves as an intermediary that decouples the high-supply voltage operation from direct leakage current paths. By inserting the clamping transistor and resistor between critical nodes and ground, the circuit enables high-voltage level conversion while the intermediary components restrict excessive current flow.
Solution Approach 2:
The patent extracts and isolates the leakage current path from the main signal path by introducing the clamping circuit. The clamping transistor selectively connects to ground only when necessary to limit leakage, separating the voltage conversion function from the leakage control function.
3Ease of operation
If the inverter is used for voltage level shifting, then voltage conversion is achieved, but current leakage occurs at the first node
Solution Approach 1:
The clamping circuit is positioned as an intermediary at the first node, where it directly addresses the leakage issue. The clamping transistor and resistor combination provides a controlled path that prevents excessive current leakage while maintaining the inverter's voltage shifting capability.
Solution Approach 2:
The clamping circuit provides preliminary protection against leakage current by being pre-configured at the first node. Before significant leakage can occur, the clamping transistor is ready to activate and limit the current flow, preventing harmful effects before they manifest.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution significantly reduces leakage current across various voltage supply paths, enhancing the reliability and efficiency of level-shifting operations in both low and high voltage scenarios.
Implementation Method 1
using a clamping circuit with a Schottky barrier diode and native NMOS transistor to restrict current flow
Data Source
AI summary
In one general aspect, a level-shifting circuit includes a first supply terminal configured to receive a first supply voltage, and a second supply terminal configured to receive a second supply voltage different from the first supply voltage. The level-shifting circuit includes a shifting circuit having electrical connections to an input terminal and an output terminal and configured to, in response to a first voltage at a first node, produce a second voltage at a second node. The shifting circuit is used to shift a first voltage level to a second voltage level. The level-shifting circuit includes a clamping circuit having an electrical connection to the first node where the clamping circuit is configured to limit current at the first node from flowing to a ground.