RF Module Isolation Switching for Reliable Sleep Mode
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Solution Overview
Problem
Radio frequency modules for wireless communication devices face challenges in achieving both size reduction and low power consumption while maintaining reliable power saving modes, particularly in ensuring isolation characteristics during sleep modes without compromising communication performance.
Innovation Solution
A radio frequency module design that includes a power amplifier circuit, first and second transistors, and control circuitry to manage power supply voltages, allowing for reliable power saving operations by maintaining transistor states even when power supply voltages become indefinite, thereby enhancing isolation characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by stationary object
If the power supply voltage is stopped during power saving mode, then power consumption is reduced, but the transistor states cannot be maintained and isolation characteristics deteriorate
Solution Approach 1:
The control circuit generates a hold control signal before stopping the power supply voltage to maintain transistor states in a predetermined condition (either ON or OFF state). This preliminary action ensures that the transistors remain in the desired state even after power is removed, preventing unwanted signal leakage and maintaining isolation characteristics during power saving mode.
Solution Approach 2:
The control circuit acts as an intermediary between the power amplifier circuit and the transistors during power saving mode. It generates hold control signals that mediate the transition to power saving mode, ensuring that transistors are properly biased before power removal. This intermediary control mechanism allows the system to achieve both low power consumption and maintained isolation characteristics.
2Use of energy by stationary object
If the transistor is turned off during power saving mode, then power consumption is reduced, but unwanted radio wave emission occurs due to loss of isolation characteristics
Solution Approach 1:
The control circuit generates a hold control signal in advance before stopping power supply to the amplifier circuit. This hold signal maintains the transistor in a predetermined OFF state with proper biasing, ensuring isolation characteristics are preserved. By taking this preliminary action, the system prevents unwanted radio wave emission while achieving power savings.
Solution Approach 2:
The control circuit changes the parameter states of the transistor by applying hold control signals that set the transistor to a predetermined condition (specific bias voltage levels). This parameter change ensures the transistor remains in a stable OFF state with maintained isolation characteristics, preventing harmful radio wave emission during power saving mode.
3Device complexity
If the amplifier circuit is stopped for size reduction, then device complexity is reduced, but control precision during power saving mode cannot be maintained
Solution Approach 1:
The invention extracts the essential control function from the full amplifier circuit by implementing a simplified control mechanism that only activates during mode transitions. The control circuit generates hold control signals selectively during power saving mode entry, removing the need for continuous complex control while maintaining necessary precision when needed. This extraction allows size reduction without sacrificing control precision during critical operations.
Data Source
AI summary
A radio frequency module is configured to enter a power saving mode with high reliability. The radio frequency module includes, e.g., a first switch transistor for coupling a transmission node to an antenna, a second switch transistor for shunting the transmission node to a ground voltage, and a level shift circuit for performing on-off control of the first and second switch transistors by positive and negative power supply voltages. The level shift circuit, upon receiving a sleep instruction while the module is in a transmission operation mode in which the first switch transistor for coupling a transmission node to an antenna is turned on and the second switch transistor for shunting the transmission node to a ground voltage is turned off, first transitions to an isolation operation mode in which the first switch transistor for coupling a transmission node to an antenna is turned off and the second switch transistor for shunting the transmission node to a ground voltage is turned on for a first period of time, and then transitions to a sleep mode in which the positive and negative power supply voltages are deactivated.