Power RF Switch Gate Boosting for Low-Voltage Switching
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Solution Overview
Problem
Power RF switches face challenges in maintaining performance specifications like insertion loss and harmonic distortion as system supply voltages decrease, and high-voltage transistors struggle with poor performance at low switching control voltages, leading to transistor breakdown risks.
Innovation Solution
Applying a boosted switching control signal that swings between a boosted supply voltage and a negative supply voltage to the gate of a high-voltage transistor, synchronized with a substrate control signal, and incorporating a voltage limiting circuit to prevent transistor breakdown.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a high-voltage transistor is used to ensure operation under absolute maximum rating condition, then reliability is improved, but performance at low switching control voltage deteriorates
Solution Approach 1:
The patent applies voltage boosting to change the parameter of switching control voltage from low level to boosted level, enabling the high-voltage transistor to operate effectively. A voltage booster circuit increases the control voltage applied to the gate of the high-voltage transistor, resolving the contradiction between reliability under maximum rating and ease of operation at low voltage.
2Use of energy by moving object
If system supply voltage is decreased for low-power operation, then energy consumption is reduced, but RF switch performance deteriorates
Solution Approach 1:
The patent uses voltage boosting to change the control voltage parameter independently from the system supply voltage. While the system operates at low supply voltage for energy efficiency, the voltage booster circuit generates a higher control voltage to maintain proper RF switch performance, thus resolving the contradiction between low power consumption and performance specifications.
Solution Approach 2:
The voltage booster circuit acts as an intermediary between the low-voltage power supply and the high-voltage transistor control requirement. It mediates the voltage level mismatch, allowing the system to run at low power while maintaining the necessary control voltage for optimal RF switch performance.
3Ease of operation
If boosted supply voltage is applied to gate of high-voltage transistor to improve switching characteristics, then ease of operation is improved, but risk of transistor breakdown increases
Solution Approach 1:
The patent incorporates a voltage limiting circuit that provides beforehand protection against excessive voltage. The voltage limiter is designed to clamp the boosted voltage at a safe level, preventing transistor breakdown while still allowing sufficient voltage for improved switching characteristics. This cushioning mechanism resolves the contradiction between ease of operation and reliability.
4Ease of operation
If voltage boosting circuit is added to improve low-voltage performance, then ease of operation is improved, but device complexity increases
Solution Approach 1:
The voltage booster circuit is designed to serve multiple functions: it boosts the control voltage for improved switching characteristics, operates from the existing low-voltage supply, and integrates with the existing RF switch structure. This multi-functionality approach minimizes the added complexity while achieving the desired performance improvement.
Data Source
AI summary
A power radio frequency (RF) switch used in wireless communication is disclosed. A boosted switching control signal, which swings between a boosted supply voltage in which a system supply voltage is boosted and a negative supply voltage in which a polarity of the system supply voltage is inverted, is applied to a gate of a high-voltage transistor. Further, a substrate control signal which is synchronized with the boosted switching control signal, and swings between the negative supply voltage and a reference voltage may be applied to a substrate of the high-voltage transistor thereof.