Pulse-Latched Level Shifter for Low-Distortion Signal Transfer
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Solution Overview
Problem
Conventional level shifters cause distorted signaling due to mismatch in delay, rise and fall times, and supply voltage noise, leading to performance degradation in integrated circuits operating at different voltage levels.
Innovation Solution
A low distortion level shifter is implemented using pulse generation circuitry that generates multiple short-duration pulses based on input signal edges, combined with a latch circuit and shaper circuit to produce a low distortion output signal, utilizing cross-coupled device pairs and inverter chains to achieve high-speed level shifting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional level shifter is used to shift voltage levels between digital and I/O domains, then voltage level conversion is achieved, but signal distortion occurs due to mismatch in delay, rise and fall times, and supply voltage noise
Solution Approach 1:
The level shifter is divided into multiple independent functional blocks: a first level shifter for initial voltage conversion, a pulse generation circuit for creating timing signals, a latch circuit for edge detection and signal conditioning, and a shaper circuit for final signal refinement. This segmentation allows each block to be optimized independently, reducing overall signal distortion while maintaining manageable complexity.
Solution Approach 2:
The pulse generation circuit generates pulses in advance based on edges detected from the level-shifted signal before the signal is fully processed. This preliminary action allows the latch circuit to be properly prepared and synchronized, ensuring accurate edge detection and minimizing distortion in the final output signal.
2Productivity
If conventional level shifting circuitry is implemented, then voltage level conversion is achieved, but performance degradation occurs due to distortion in clock or data signaling
Solution Approach 1:
The latch circuit receives feedback from the level-shifted signal edges and uses this information to generate appropriately timed pulses. This feedback mechanism ensures that the output signal accurately reflects the input signal transitions, maintaining signal integrity even at high data transmission speeds. The shaper circuit further refines this feedback-based output to eliminate residual distortion.
Solution Approach 2:
The circuit processes signals through periodic edge detection and pulse generation cycles. The latch circuit triggers on rising and falling edges in a systematic periodic manner, ensuring consistent timing relationships between input and output signals. This periodic action maintains signal integrity across varying data rates by providing regular, predictable signal conditioning.
3Reliability
If the pulse width is increased to ensure proper latching, then reliable edge detection is achieved, but the pulse width exceeds the gate delay of the latch circuit causing distortion
Solution Approach 1:
The circuit dynamically adjusts the pulse width parameter based on the specific timing requirements of the latch circuit. The pulse generation circuit is designed to produce pulses with widths specifically calibrated to match the latch circuit's gate delay characteristics. This parameter optimization ensures reliable latching operation while preventing excessive pulse widths that would cause distortion, achieving both reliability and precision.
Data Source
AI summary
In one embodiment, a method includes: receiving, in a level shifter, an input signal from a first voltage domain that operates according to a first supply voltage; level shifting the input signal to at least one level-shifted signal having a second voltage greater than the first supply voltage; based on the at least one level-shifted signal, generating a first pulse signal and a second pulse signal; latching the first pulse signal through a latch circuit to form an output signal; and outputting the output signal to a second voltage domain, the second voltage domain to operate according to a second supply voltage greater than the first supply voltage.