Bootstrap Analog Switches for High-Voltage Signals Without HV Supplies
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Solution Overview
Problem
Existing analog switch designs for high voltage signals require high voltage power supplies, leading to complex board layouts, increased manufacturing costs, safety hazards, and limitations in flexibility and feasibility with nominal BCD processes.
Innovation Solution
The design of improved analog switches that terminate to ground instead of high voltage negative power supplies, utilizing translinear loops and a bootstrap configuration to maintain constant on-resistance and eliminate harmonic distortion, allowing for flexible on-resistance and termination voltage without high voltage DC power supplies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high voltage power supplies are used in analog switch design, then high voltage signal transmission capability is achieved, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent extracts and eliminates the high voltage power supply component from the analog switch design. By using standard low voltage power supplies (e.g., ±5V) combined with level shifting circuits and isolated ADCs, the design removes the need for high voltage power supplies, thereby simplifying board layout and reducing manufacturing complexity while maintaining high voltage signal transmission capability through signal conditioning techniques
Solution Approach 2:
The patent introduces intermediary circuits including level shifters and isolated ADCs that act as mediators between the high voltage signal path and the low voltage digital processing path. These intermediary components enable high voltage signal acquisition without requiring the entire system to operate at high voltage, thus reducing device complexity while preserving the core functionality
2Reliability
If high voltage power supplies are used in analog switch design, then high voltage signal transmission capability is achieved, but manufacturing cost increases
Solution Approach 1:
The patent extracts and eliminates the high voltage power supply component from the analog switch design. By using standard low voltage power supplies (e.g., ±5V) combined with level shifting circuits and isolated ADCs, the design removes the need for high voltage power supplies, thereby simplifying board layout and reducing manufacturing complexity while maintaining high voltage signal transmission capability through signal conditioning techniques
Solution Approach 2:
The patent employs commercially available isolated ADCs and level shifter ICs that are mass-produced and relatively inexpensive. These off-the-shelf components replace custom high voltage circuitry, reducing manufacturing cost through economies of scale and standardized production processes
3Reliability
If high voltage power supplies are used in analog switch design, then high voltage signal transmission capability is achieved, but safety hazards increase
Solution Approach 1:
The patent segments the system into isolated high voltage signal path and low voltage digital processing path. By using isolated ADCs and level shifting circuits, the design creates electrical isolation barriers that prevent high DC voltages from propagating to sensitive digital circuits and user-accessible areas, thereby eliminating safety hazards while preserving high voltage signal transmission capability in the measurement path
Solution Approach 2:
The patent introduces intermediary circuits including level shifters and isolated ADCs that act as mediators between the high voltage signal path and the low voltage digital processing path. These intermediary components enable high voltage signal acquisition without requiring the entire system to operate at high voltage, thus reducing device complexity while preserving the core functionality
4Reliability
If high voltage power supplies are used in analog switch design, then high voltage signal transmission capability is achieved, but adaptability to nominal BCD processes decreases
Solution Approach 1:
The patent extracts and eliminates the high voltage power supply component from the analog switch design. By using standard low voltage power supplies (e.g., ±5V) combined with level shifting circuits and isolated ADCs, the design removes the need for high voltage power supplies, thereby simplifying board layout and reducing manufacturing complexity while maintaining high voltage signal transmission capability through signal conditioning techniques
Solution Approach 2:
The patent changes the operating voltage parameters of the analog switch from high voltage to low voltage. By using level shifting circuits and isolated ADCs, the design enables the analog switch to operate at standard low voltages compatible with nominal BCD processes, while still handling high voltage signals through the level shifting mechanism
Data Source
AI summary
Described herein are multiple designs for an improved analog switch for use in transmitting high voltage signals without using high voltage power supplies for the switch. The analog switches are able to pass and block input signals in the approximate range of −100 V to +100 V. The use of translinear loops and a bootstrap configuration results in a constant on-resistance of the symmetrical switches and matches the conductance of each analog switch to the transconductance of an NMOS transistor, which can be easily stabilized with a constant gm biasing scheme. In certain embodiments, a shunt termination (T-switch) configuration is used for better off-isolation, and each of the symmetrical switches has its own translinear loop and thus flexibility of on-resistance and termination voltage.