High-Voltage Switch Circuit Using Elevator-Controlled Low-Voltage Transistors
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Solution Overview
Problem
Conventional high-voltage switch circuits rely on high-voltage rating transistors, leading to increased manufacturing costs due to thick gate oxide, large area occupation, and dedicated manufacturing steps.
Innovation Solution
A switch circuit design using low-voltage rating transistors with elevator circuits that shift control signals to higher voltage domains, allowing the circuit to manage high voltages without requiring high-voltage rated devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high-voltage rating transistors are used to handle high voltages (0 V to 5 V), then the circuit can switch between high voltage and low voltage, but the manufacturing cost increases due to thick gate oxide, large area occupation, and dedicated manufacturing steps
Solution Approach 1:
Elevator circuits are introduced as intermediary voltage-shifting devices that translate low-voltage control signals (0 V to 2.5 V) into high-voltage control signals (0 V to 5 V). This allows low-voltage transistors to control high-voltage switches without requiring the transistors themselves to be rated for high voltage, thereby reducing manufacturing costs while maintaining voltage handling capability
Solution Approach 2:
The patent changes the voltage parameter of control signals through elevator circuits. By shifting the voltage level of control signals from low-voltage domain (0 V to 2.5 V) to high-voltage domain (0 V to 5 V), the system enables low-voltage transistors to effectively control high-voltage switches, resolving the contradiction between voltage handling and manufacturing cost
2Reliability
If high-voltage rating transistors are used, then the circuit can operate at high voltages up to 5 V, but the area occupation increases due to thick gate oxide and large device sizing
Solution Approach 1:
Elevator circuits serve as voltage-level intermediaries that allow low-voltage transistors (with smaller area) to control high-voltage switches. The elevator circuits shift control signals from low-voltage to high-voltage domains, enabling high-voltage operation without requiring physically large high-voltage transistors, thus reducing overall circuit area
Solution Approach 2:
The control function is segmented into two parts: low-voltage control signals generated by standard logic circuits, and high-voltage control signals produced by elevator circuits. This segmentation allows the use of compact low-voltage transistors for control functions while maintaining high-voltage capability through the elevator circuit mechanism
3Reliability
If high-voltage rating transistors are implemented, then the switch circuit can handle high voltages, but dedicated manufacturing steps and masks are required increasing complexity
Solution Approach 1:
Elevator circuits act as intermediary devices that bridge the gap between low-voltage control logic and high-voltage switches. By introducing these voltage-shifting intermediaries, the patent eliminates the need for dedicated high-voltage transistor manufacturing steps and masks, as standard low-voltage transistors can be used throughout the process
Solution Approach 2:
The elevator circuits provide multi-functionality by serving both as voltage shifters and as level translators. They enable the same manufacturing process and transistor design to be used across different voltage domains, eliminating the need for separate high-voltage device fabrication processes and reducing overall manufacturing complexity
Data Source
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AI summary
A switch circuit (30) includes a first (301) and a second (302) input nodes to receive a first (Vin1) and a second (Vin2) input voltages, and an output node (304) to produce an output voltage (Vout) switchable between the first and second input voltages. A first (P1a) and a second (P1b) pass devices are arranged in series between the first input node and the output node. A third (P2a) and a fourth (P2b) pass devices are arranged in series between the second input node and the output node. A first (321a), a second (321b), a third (322a) and a fourth (322b) elevator circuits control, respectively, the first (P1a), second (P1b), third (P2a) and fourth (P2b) pass devices. The first elevator circuit is biased between the first input voltage and a shifted ground voltage (s_GND). The third elevator circuit is biased between the second input voltage and a ground voltage (GND) . The second and fourth elevator circuits are biased between the output voltage (Vout) and an elevated ground voltage (e_GND).