Level-Shifter Boost Circuit for Faster Rising Edge Translation
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Solution Overview
Problem
Existing level-shifters face challenges in efficiently transmitting data between IC domains with different voltage levels, requiring large input transistors to compensate for voltage differences, which increases footprint and optimizes for a single transition edge, leading to inefficiencies.
Innovation Solution
A level-shifter with a boost circuit that provides a 'one-shot' current pulse at the transitioning edge, using larger PFETs in parallel with smaller PFETs to enhance rising edge speed without affecting the P/N transistor ratio, thereby reducing the overall footprint and improving transition edge delays.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional level-shifters use large input transistors to compensate for voltage differences, then the voltage domain translation reliability is improved, but the circuit footprint increases
Solution Approach 1:
The level-shifter circuit is segmented into distinct functional blocks: input circuitry, output circuitry, and a separate boost circuit. This segmentation allows each block to be optimized independently, enabling the use of smaller transistors in the main signal path while adding a dedicated boost circuit for voltage compensation, thereby reducing overall footprint while maintaining reliability
Solution Approach 2:
A boost circuit acts as an intermediary element between the input and output circuitry. This boost circuit provides the necessary voltage compensation and current boosting without requiring the main input transistors to be oversized, thus achieving reliable voltage domain translation with a reduced circuit footprint
2Speed
If conventional level-shifters optimize for a single transition edge, then the performance for that specific transition is improved, but the overall data transmission efficiency decreases
Solution Approach 1:
The level-shifter design provides universal performance for both rising and falling transition edges through symmetric circuit configuration. The input and output circuitry are designed to handle both transition types effectively, and the boost circuit can be applied to either edge as needed, achieving multi-functionality that improves overall data transmission efficiency rather than optimizing for a single transition type
3Ease of manufacture
If conventional level-shifters use symmetric transistor sizing, then the circuit design simplicity is maintained, but the transition edge performance is suboptimal
Solution Approach 1:
The circuit employs local quality optimization by using differently sized transistors in specific locations within the circuit. The boost circuit contains transistors with optimized sizing for their specific function of providing current boosting during transitions, while the main signal path transistors maintain appropriate sizing for their switching function, achieving optimal transition edge performance without sacrificing manufacturability
Data Source
AI summary
The disclosure introduces a level-shifter including a boost circuit that provides a “one-shot” pulse (a self-annihilating pulse) with the transitioning edge of the output signal. The pulse can be used to produce a faster output rise time and reduce the overall footprint of a level-shifter compared to conventional level-shifters. In one example the level-shifter includes: (1) input circuitry configured to receive one or more input signals from one or more input voltage domains, (2) output circuitry configured to provide an output signal, based on at least one of the one or more input signals, for an output voltage domain, wherein an operating voltage of the output voltage domain is greater than an operating voltage of the one or more input voltage domains, and (3) a boost circuit connected to the output circuitry and configured to provide a current pulse for a transition edge of the output signal.