RF Switch Controller Using Shared LDO Sleep Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing radio-frequency switch controllers face challenges in managing power consumption and leakage current, especially when operating over a wide voltage range and in environments with varying process, voltage, and temperature conditions, without the use of external power down pins.
Innovation Solution
A controller architecture utilizing a low-dropout regulator (LDO) that generates multiple reference voltage levels and can enter a sleep mode, controlled by a common input node through a mode detector, eliminating the need for a dedicated power down pin, and incorporating a low-power bandgap circuit and error amplifier to manage leakage current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a dedicated power down pin is used to control the low-dropout regulator, then the regulator can enter sleep mode to conserve power, but the device complexity increases due to additional pins and control circuitry
Solution Approach 1:
The patent combines the power down control functionality with the existing common input node that controls the switch operation. The mode detector circuit monitors the control signal at this shared node and automatically generates the appropriate power down signal for the LDO regulator, eliminating the need for a separate dedicated power down pin and reducing device complexity while maintaining power savings capability.
Solution Approach 2:
The common input node is designed to serve multiple functions: it controls the switch operation during normal mode and simultaneously serves as the input for power down control during sleep mode. This multi-functional design allows the system to conserve power without requiring additional dedicated pins, thereby reducing device complexity while achieving power management goals.
2Adaptability or versatility
If the low-dropout regulator operates over a wide voltage range, then the adaptability of the controller improves, but the leakage current increases
Solution Approach 1:
The patent implements dynamic voltage selection where the LDO regulator automatically adjusts its output voltage level based on the operating mode detected by the mode detector. During sleep mode, the regulator transitions to a lower voltage state that minimizes leakage current, while in normal operation mode, it provides the higher voltage levels needed for full switch operation. This dynamic adaptation allows the system to maintain wide voltage range compatibility while minimizing harmful leakage current in low-power states.
Solution Approach 2:
The system changes the voltage parameter dynamically based on operational requirements. The LDO regulator is designed to output different voltage levels depending on the control signal state: higher voltages for normal switch operation to ensure proper biasing and lower voltages during sleep mode to reduce leakage. This parameter change strategy enables the controller to adapt to wide voltage ranges while controlling leakage current through appropriate voltage selection.
3Reliability
If multiple reference voltage levels are generated for switch operation, then the switch can operate reliably in varying conditions, but the power consumption increases
Solution Approach 1:
The patent implements periodic or conditional generation of reference voltage levels based on the operational mode. The mode detector circuit monitors the control signal and only activates the full multi-level reference voltage generation when normal operation is detected. During sleep mode, the reference voltage generation is reduced or suspended, significantly lowering power consumption while maintaining the capability to provide multiple reference levels when reliability is required during active operation.
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 achieves low leakage current, efficient power management, and compatibility with wide voltage ranges, ensuring reliable operation in varying conditions while minimizing power consumption.
Implementation Method 1
The low-dropout regulator can include an error amplifier configured to be controlled by the control signal from the mode detector, and to generate an output voltage Vout based on inputs including the bandgap reference voltage and a feedback voltage
Implementation Method 2
the controller can further include a low power bandgap circuit configured to provide a bandgap reference voltage to the low-dropout regulator
Implementation Method 3
The low-dropout regulator can further include a plurality of source followers implemented in series with one end connected to a drain of the second transistor and the other end coupled to ground, such that a source of each of the source followers provides a respective reference voltage levels
Data Source
AI summary
A radio-frequency switch can include a switching circuit and a control circuit configured to control operation of the switching circuit. The control circuit can include a regulator configured to generate a plurality of reference voltage levels for the operation of the switching circuit, or to be in a sleep mode, based on a control signal received through a common input node. The control circuit can further include a mode detector in communication with the regulator and configured to provide a first form of the control signal to the common input node to allow the plurality of reference levels to be generated by the regulator, or a second form of the control signal to the common input node to put the regulator in the sleep mode.