Single-Supply Voltage Level Shifter With Capacitive Voltage Boost
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Solution Overview
Problem
Existing voltage level shifters require dual supply voltages to operate, making them impractical for interfacing circuit units with different operating voltage swings, as they cannot perform voltage level shifting based on a single supply voltage.
Innovation Solution
A voltage level shifter with a voltage boost mechanism comprising specific transistors, capacitors, and inverters that allows for voltage level shifting using a single supply voltage, enabling the conversion of a low operating voltage swing to a high operating voltage swing without a dual voltage generator.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a voltage level shifter uses dual supply voltages to perform voltage level shifting, then the voltage level shifting function is achieved, but the device complexity and requirement for dual voltage generator increase
Solution Approach 1:
The voltage level shifter uses its own input signal to control the switching of transistors, which in turn controls the charging and discharging of capacitors to generate the boosted voltage. The circuit serves itself by using the input signal to drive the voltage boosting mechanism, eliminating the need for external dual voltage generators
Solution Approach 2:
The capacitors are pre-charged to the supply voltage Vdd during the low phase of the input signal. This preliminary charging action enables the capacitors to subsequently provide the necessary voltage boost when the input signal goes high, allowing the circuit to generate the required voltage levels in advance
2Adaptability or versatility
If a voltage level shifter interfaces between low-voltage and high-voltage circuit units, then the interface function is achieved, but the requirement for voltage generator increases
Solution Approach 1:
The voltage level shifter circuit performs multiple functions: it acts as a voltage level shifter to interface between different voltage domains, simultaneously functions as a voltage booster to generate high voltage from low voltage, and operates as a buffer to drive signals. This multi-functionality eliminates the need for separate voltage generator circuits
Solution Approach 2:
The patent combines the voltage level shifting function with the voltage boosting function into a single integrated circuit. The switching transistors and capacitors that could have been separate voltage generation components are merged with the level shifting circuit, simplifying the overall system and improving ease of manufacture
Data Source
AI summary
A voltage level shifter with voltage boost mechanism is disclosed for interfacing two circuit units having different operating voltage swings. The voltage level shifter includes a first inverter, a second inverter, a first capacitor, a second capacitor and a plurality of transistors. The input and power ends of the first inverter function to receive an input voltage and a first voltage respectively. The output end of the second inverter functions to provide an output voltage. When the input voltage is a ground voltage, the output voltage is also a ground voltage; meanwhile, the switches are controlled for charging the first and second capacitors to a second voltage and a third voltage respectively. When the input voltage is the first voltage, a sum voltage of the first, second, and third voltages is furnished to the power end of the second inverter for providing the sum voltage as the output voltage.