Switched Level Shifter Topology for Low-Pin Voltage Conversion
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Solution Overview
Problem
In systems on chip (SoC) with varying voltage requirements, conventional level shifters increase manufacturing costs and design complexity due to the need for additional power pins to manage leakage currents between high and low voltage blocks.
Innovation Solution
A level shifter design utilizing a signal converter connected to an external power source and ground, with a switching unit comprising transistors of different types to adjust output voltage levels, allowing for single power source operation and reducing the number of power pins required.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If additional power pins are used to manage leakage currents in conventional level shifters, then voltage level conversion between high and low voltage blocks is achieved, but manufacturing cost and design complexity increase
Solution Approach 1:
The patent merges the power supply function into a single shared power pin that serves both high voltage and low voltage blocks. The level shifter circuit shares this power source through a switching mechanism that dynamically connects the appropriate voltage level to the power pin based on the operating mode, eliminating the need for separate power pins for each voltage block.
Solution Approach 2:
The patent employs dynamic switching of the power pin connection state based on the input signal level. When the input signal is at a high level, the power pin is connected to the high voltage block; when the input signal is at a low level, the power pin is connected to the low voltage block. This dynamic reconfiguration allows a single power pin to serve multiple voltage levels.
2Reliability
If additional power pins are used in conventional level shifters, then leakage current control is improved, but manufacturing cost increases
Solution Approach 1:
The patent combines multiple power supply functions into a single power pin, reducing the total number of pins required for manufacturing. This consolidation maintains leakage current control capabilities while simplifying the manufacturing process and reducing production costs.
Solution Approach 2:
The single power pin is designed to serve multiple functions: it can supply power to both high voltage and low voltage blocks, and it can dynamically adapt its voltage level based on the operating conditions. This multi-functionality eliminates the need for separate dedicated power pins for each voltage block.
3Reliability
If conventional level shifters use separate power sources for high and low voltage blocks, then voltage level conversion is achieved, but the number of pins increases
Solution Approach 1:
The patent merges separate power sources for high and low voltage blocks into a single shared power pin. The switching circuitry dynamically connects the appropriate voltage level to this single pin based on the input signal, reducing the total pin count while maintaining voltage level conversion functionality.
Solution Approach 2:
The power pin's voltage level is dynamically adjusted based on the input signal state. The switching mechanism changes the connection state of the power pin to match the required voltage level, allowing one pin to replace what would traditionally require two separate pins.
Data Source
AI summary
A level shifter is provided. The level shifter includes a signal converter connected to an external power source and a ground, first and second output terminals connected to the signal converter, the first and second output terminals being configured to output a bias voltage applied from the external power source, and a switching unit configured to switch a connection state of the signal converter according to an input signal to adjust output voltage values of the first and second output terminals, the switching unit including first and second transistors, the first transistor being of a type that is different from a type of the second transistor, the first and second transistors being connected to each other in series between an input terminal, to which an input signal is applied, and the external power source, gates of the first and second transistors being commonly connected to the second output terminal.