Power-On Voltage Generation for Native-Free Level Shifters
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Solution Overview
Problem
Existing voltage level shifter circuits in integrated circuits require native transistors, which occupy a large area and increase costs, and fail to prevent dead zone conditions and IO crowbar currents during power-up.
Innovation Solution
A voltage generating circuit based on a power-on control (POC) signal that generates a control voltage without using native transistors, reducing the area of the level shifter by about 80% and improving IO speed, and eliminating the need for expensive mask manufacturing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a native transistor is used in the level shifter, then the voltage level shifting function is achieved, but the die area increases by about 30% and manufacturing cost increases
Solution Approach 1:
The patent extracts and removes the native transistor from the level shifter circuit, replacing it with a standard transistor operated in the triode region. This extraction eliminates the need for expensive native transistor masks while maintaining the voltage level shifting function through alternative circuit topology using readily available standard transistors.
Solution Approach 2:
The patent changes the operating parameters of standard transistors by utilizing the triode region operation instead of requiring native transistors. By adjusting gate voltages and operating points, the standard transistors achieve the required voltage level shifting behavior that previously required native transistors, thereby reducing die area and manufacturing cost.
2Reliability
If a power-on control circuit is added to prevent unknown states, then IO crowbar current is reduced, but the die area and manufacturing cost increase due to native transistor requirements
Solution Approach 1:
The patent merges the power-on control functionality with the existing level shifter circuit by integrating control logic that manages transistor switching during power-up. This integration eliminates the need for separate native transistors in the control circuit, achieving IO state control while maintaining area efficiency through shared circuit elements and standard transistor implementation.
3Area of stationary object
If standard transistors are used instead of native transistors, then die area and manufacturing cost are reduced, but dead zone conditions may occur during power-up
Solution Approach 1:
The patent implements preliminary control actions during power-up by using control signals that pre-establish appropriate voltage levels and transistor states before full operation begins. This preliminary action prevents dead zone conditions by ensuring that standard transistors are properly biased and controlled from the start of power-up, eliminating the reliability issues that would otherwise require native transistors.
Data Source
AI summary
A voltage generating circuit includes a first supply voltage node, a first switching device, a sub voltage generating circuit, and a second switching device. The first supply voltage node is configured to have a first supply voltage value, and is coupled with the first switching device. The sub voltage generating circuit is coupled in between the first switching device and the second switching device. The first switching circuit and the second switching circuit are configured to receive a control signal behaving based on the first supply voltage value and a second supply voltage value different from the first supply voltage value.