Level Shifter Circuit With One-Shot Pulses for Duty Cycle Integrity
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Solution Overview
Problem
Existing level shifter circuits in semiconductor devices face challenges in maintaining signal characteristics and duty cycle integrity due to variations in transistor characteristics and changes in input signal voltages, leading to duty cycle distortion and unsuitability for applications with varying source voltages.
Innovation Solution
The implementation of a level shifter circuit that includes a splitter circuit, a one-shot pulse generator circuit, and a mixer circuit to restore the interval between rising and falling edges of the input signal without duty cycle distortion, using complementary signals and one-shot pulse signals to maintain the duty cycle of the output signal similar to the input signal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by stationary object
If a conventional level shifter circuit with series inverters is used to convert high voltage signals to low voltage signals, then power consumption is reduced and peripheral voltage is provided, but duty cycle distortion occurs and signal characteristics change due to different threshold levels
Solution Approach 1:
The level shifter circuit is divided into multiple independent functional blocks: a first level shifter block for initial voltage conversion, a duty cycle correction block for restoring duty cycle accuracy, and a second level shifter block for final voltage conversion. Each block performs a specific function, allowing the overall system to achieve both power efficiency and duty cycle precision that cannot be achieved by a simple series inverter configuration.
2Manufacturing precision
If transistor sizes are adjusted to correct duty cycle distortion, then duty cycle accuracy improves, but device complexity and manufacturing difficulty increase
Solution Approach 1:
A duty cycle correction block is introduced as an intermediary component between the first and second level shifter blocks. This correction block receives the output signal from the first level shifter, corrects its duty cycle using buffered versions of the signal and controlled switching, and provides the corrected signal to the second level shifter. This intermediary approach maintains duty cycle accuracy without requiring complex transistor size adjustments throughout the entire circuit.
3Ease of manufacture
If the level shifter circuit uses fixed threshold levels for signal conversion, then circuit design is simplified, but the circuit becomes unsuitable for applications with varying source voltages
Solution Approach 1:
The level shifter circuit employs dynamic threshold adjustment mechanisms where the threshold levels are not fixed but adapt based on the input signal characteristics. The duty cycle correction block uses buffered versions of the input signal and controlled switching to dynamically adjust the effective threshold levels, allowing the circuit to maintain proper operation across varying source voltages while preserving the basic simplicity of the inverter-based architecture.
Data Source
AI summary
Apparatuses and methods for level shifting in a semiconductor device are described. An example apparatus includes: a splitter circuit that operates on a first voltage potential to produce a first signal having a first polarity and a second signal having a second polarity that is substantially opposite to the first polarity; an one-shot pulse circuit that operates on the first voltage potential to produce a first one-shot pulse signal responsive to the first signal and a second one-shot pulse signal responsive to the second signal; and a logic circuit configured to operate on a second voltage potential to produce a third signal responsive to the first and second one-shot pulse signals, the second voltage potential being different from the first voltage potential.