Output Driver Clamping Circuit for Active Overvoltage Protection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing USB output drivers face challenges in providing efficient and robust active overvoltage protection without increasing complexity, area, and power consumption, while also being slow to react and unable to handle both positive and negative overvoltages.
Innovation Solution
An output driver design utilizing semiconductor electronic switching components with clamping circuits, including N-channel and P-channel MOSFETs, to provide active protection against both positive and negative overvoltages, with a faster response time and lower power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If passive protection components (followers, switches) are added to protect the output driver, then overvoltage protection is achieved, but device complexity and area increase significantly
Solution Approach 1:
The output driver uses its own existing transistors (first and second transistors) to provide overvoltage protection through self-regulation. When overvoltage occurs, the existing transistor structure automatically limits the voltage at the output node without requiring external protection components, making the system protect itself using its inherent components.
Solution Approach 2:
The existing transistors in the output driver serve dual functions: they act as both the output driver transistors and the protection mechanism. The first transistor drives the output while also providing overvoltage protection, and the second transistor performs similar dual functions, eliminating the need for dedicated protection components.
2Reliability
If passive protection components (followers, switches) are added to protect the output driver, then overvoltage protection is achieved, but area increases by a factor of 4
Solution Approach 1:
The output driver uses its own existing transistors (first and second transistors) to provide overvoltage protection through self-regulation. When overvoltage occurs, the existing transistor structure automatically limits the voltage at the output node without requiring external protection components, making the system protect itself using its inherent components.
Solution Approach 2:
The existing transistors in the output driver serve dual functions: they act as both the output driver transistors and the protection mechanism. The first transistor drives the output while also providing overvoltage protection, and the second transistor performs similar dual functions, eliminating the need for dedicated protection components.
3Reliability
If differential amplifier and compensation circuit are used for active protection, then overvoltage protection is provided, but response time decreases due to bandwidth limitations
Solution Approach 1:
The invention removes the differential amplifier and compensation circuit from the protection mechanism, extracting only the essential voltage limiting function. By using direct transistor voltage clamping without amplification stages, the system achieves fast response time while maintaining overvoltage protection.
Solution Approach 2:
The protection mechanism skips the slow amplification and compensation stages by directly clamping the output voltage through the transistor gate control. When overvoltage occurs, the voltage limit is applied immediately through the transistor's inherent characteristics rather than through multi-stage amplification, rushing through the protection action without delay.
4Speed
If switch and transitions detector are added to disconnect compensation circuit, then response time is improved, but device complexity increases
Solution Approach 1:
The invention removes the differential amplifier and compensation circuit from the protection mechanism, extracting only the essential voltage limiting function. By using direct transistor voltage clamping without amplification stages, the system achieves fast response time while maintaining overvoltage protection.
Solution Approach 2:
The protection mechanism skips the slow amplification and compensation stages by directly clamping the output voltage through the transistor gate control. When overvoltage occurs, the voltage limit is applied immediately through the transistor's inherent characteristics rather than through multi-stage amplification, rushing through the protection action without delay.
5Area of stationary object
If active protection circuit is implemented, then overvoltage protection is provided without additional followers, but existing solutions only protect against positive overvoltage not negative
Solution Approach 1:
The transistor structure provides universal protection against both positive and negative overvoltage conditions. The same first and second transistors that drive the output also clamp both positive and negative voltage excursions, making the protection mechanism versatile without requiring separate protection circuits for different voltage polarities.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution offers simple, stable, and efficient overvoltage protection with a faster reaction time, reduced area, and controlled power consumption, effectively clamping the output driver from both positive and negative overvoltages.
Implementation Method 1
The semiconductor electronic switching component of the second type is in saturation mode
Implementation Method 2
an exponential increase of the current in the resistor
Data Source
Figure 1~2
Figure 3~4
AI summary
The present invention concerns an output driver (12), comprising: - a first supply rail (13A) configured to receive a high supply electrical voltage (Vdd); - a second supply rail (13B) configured to receive a low supply electrical voltage (Vss); - a pad terminal (15) configured to output an output electrical voltage (V_pad_out); - an output stage (14) connected to the pad terminal (15) and to the first and second supply rails (13A, 13B); the output stage (14) comprising at least one electrical clamping circuit (18A, 18B) comprising a semiconductor electronic switching component (Q3, Q6) made of a first type of semiconductors and a semiconductor electronic switching component (Q4, Q7) made of a second type of semiconductors, each connected between the pad terminal (15) and said first or second supply rail; a resistor (R3, R0) connected between said first or second supply rail and the semiconductor electronic switching component (Q3, Q6) of the first type, at an intermediate terminal (20, 24), the control terminal of the semiconductor electronic switching component of the first type being biased with a constant voltage; the control terminal of the semiconductor electronic switching component of the second type being connected to said intermediate terminal (20, 24).