Level Shift Drive Circuit for Surge-Resistant Control Signals
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional driving circuits generate surge voltages that can lead to erroneous control signals due to the transmission of surge voltages to level shift circuits, causing malfunctions in subsequent stages.
Innovation Solution
The driving circuit incorporates set and reset side level shift circuits with input transistors and serial transistor units, along with buffers to manage surge voltages, ensuring that control signals are accurate by maintaining MOS transistors in appropriate states and using feedback units to complement the operation of first MOS transistors based on control signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional driving circuit is used to drive subsequent stage circuits, then the circuit can operate with simple structure, but surge voltages are generated that cause erroneous control signals and malfunctions
Solution Approach 1:
The level shift circuit is divided into separate set side and reset side circuits, each with dedicated input transistors and serial transistor units. This segmentation allows independent optimization of each side to handle surge voltages effectively while maintaining overall circuit reliability.
Solution Approach 2:
Buffers are introduced as intermediary elements between the level shift circuits and the control circuit. These buffers compare potential levels with threshold values and control MOS transistor states, acting as mediators that prevent surge voltages from directly affecting the control signal generation.
2Reliability
If level shift circuits are used to shift voltage levels from preceding stage circuits, then voltage level compatibility is achieved, but surge voltages are transmitted to the control circuit causing erroneous logical values
Solution Approach 1:
The circuit utilizes the surge voltage phenomenon by designing serial transistor units with specific MOS transistor configurations that respond to voltage changes. The buffers compare surge voltages against threshold values and convert these harmful fluctuations into controlled transistor state changes, transforming the harmful surge into a manageable control mechanism.
Solution Approach 2:
The buffers perform preliminary comparison of potential levels before control signals are generated. By anticipating surge voltage effects and taking preliminary action to control MOS transistor states based on threshold comparisons, the circuit prevents erroneous logical values from being produced in the first place.
3Reliability
If MOS transistors are used in level shift circuits for voltage level shifting, then voltage shifting functionality is achieved, but dV/dt noise causes malfunctions in the control circuit
Solution Approach 1:
The buffers implement feedback mechanisms by continuously monitoring potential levels and adjusting MOS transistor states accordingly. The comparison of potential levels with threshold values creates a feedback loop that stabilizes the control circuit against dV/dt noise, ensuring reliable operation despite rapid voltage changes.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A malfunction is prevented in a driving circuit. A driving circuit in which each of the set side level shift circuit and the reset side level shift circuit has an input transistor, a serial transistor unit which includes a first MOS transistor and a second MOS transistor which are connected in series, the first MOS transistors complementarily operate to each other, the driving circuit further has a set side buffer which compares a level of the set potential with a threshold value depending on the reference potential, and controls the reset side second MOS transistor, and a reset side buffer which compares a level of the reset potential with a threshold value depending on the reference potential, and controls the set side second MOS transistor.