Multi-Stage Voltage Level Shifter for Near-Threshold Reliability
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Solution Overview
Problem
Existing voltage level shifters in integrated circuit devices are unable to handle the voltage changes required by Near Threshold Voltage (NTV) technology, leading to operational malfunctions due to degraded transistor performance and increased power consumption in IoT and wearable electronic devices.
Innovation Solution
A voltage level shifter design incorporating a pull-down driving unit, pull-up driving unit, bias generation unit, and bias operation unit that gradually lowers the voltage level of input signals from a low voltage to a high voltage, using a cascade configuration of NMOS and PMOS transistors with varying gate thickness to manage voltage differences and ensure reliable operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the voltage level of input signals is lowered to match NTV technology requirements, then power consumption is reduced, but transistor performance is degraded and operational malfunctioning occurs
Solution Approach 1:
The voltage level shifter is divided into multiple stages including a first voltage level shifter and a second voltage level shifter. Each stage handles a portion of the voltage conversion from the low first supply voltage to the high second supply voltage, preventing any single transistor from experiencing excessive voltage stress that would degrade its performance
Solution Approach 2:
The patent introduces intermediate voltage levels (first intermediate voltage and second intermediate voltage) between the low input voltage and high output voltage. These intermediate voltages act as mediators, allowing gradual voltage transition and ensuring that transistors operate within their safe voltage ranges while still enabling the overall voltage conversion function
2Device complexity
If existing voltage level shifters are used with lowered voltage signals, then device simplicity is maintained, but transistor performance degradation occurs
Solution Approach 1:
The voltage level shifter is divided into multiple stages including a first voltage level shifter and a second voltage level shifter. Each stage handles a portion of the voltage conversion from the low first supply voltage to the high second supply voltage, preventing any single transistor from experiencing excessive voltage stress that would degrade its performance
Solution Approach 2:
Different transistors within the voltage level shifter are designed with different gate widths optimized for their specific operating conditions. Transistors handling lower voltage stages have different characteristics than those handling higher voltage stages, allowing each transistor to operate optimally within its local voltage range
Data Source
AI summary
A voltage level shifter includes: in stages a pull-down driving unit suitable for receiving an input signal swinging between a ground voltage and a first supply voltage, and pull-down driving an output node to the ground voltage according to a voltage level of the input signal, wherein an output signal outputted through the output node swings between the ground voltage level and a second supply voltage level higher than the first supply voltage; a pull-up driving unit suitable for pull-up driving the output node, to the second supply voltage according to the voltage level of the input signal; a bias generation unit suitable for generating a bias voltage fixed to a preset voltage level; and a bias operation unit coupled between the output node and the pull-down driving unit, and suitable for lowering a voltage level of the output node in stages based on the bias voltage to supply the lowered voltage to the pull-down driving unit when a pull-down operation is performed by the pull-down driving unit.