Frequency Synthesizer Dynamic Level Shifting for Lower Current
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Solution Overview
Problem
Conventional frequency synthesizers face high current consumption and design challenges due to the need for high-speed level shifting operations, especially in battery-powered devices, where reducing current consumption and maintaining maximum speed at low supply voltages and worst-case temperature conditions is crucial.
Innovation Solution
A dynamically selected level shifting operation is implemented using a multiplexer circuit to choose between the original and level-shifted oscillating output signals, allowing the frequency synthesizer to adjust power supply voltages based on the source voltage and reference voltage, thereby optimizing power management and reducing unnecessary high-speed level shifter usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If high-speed level shifting operation is implemented to maintain maximum speed, then the oscillating output signal can be processed at high frequency, but current consumption increases significantly
Solution Approach 1:
The patent implements dynamic selection of level shifting operation based on real-time frequency requirements. The system transitions from static always-on level shifting to dynamic conditional level shifting, where the level shifter is activated only when the oscillating output signal frequency exceeds a threshold value. This dynamic adaptation resolves the contradiction by matching the energy-consuming level shifting operation only to the specific condition where high-speed processing is actually needed.
Solution Approach 2:
The patent changes the operational parameter of the level shifter from a fixed state to a variable state controlled by frequency threshold comparison. By monitoring the oscillation frequency and adjusting the level shifting activation accordingly, the system optimizes the balance between speed performance and current consumption based on actual operating conditions.
2Reliability
If level shifter is always active to ensure signal level matching, then signal integrity is maintained, but power consumption increases in battery-powered devices
Solution Approach 1:
The patent implements periodic monitoring of the oscillating output signal frequency and conditional activation of the level shifter. Instead of continuous operation, the level shifting function is periodically evaluated against frequency thresholds and activated only when necessary, reducing energy loss while maintaining signal integrity when required.
Solution Approach 2:
The system uses the oscillating output signal itself to control the level shifting operation through frequency threshold comparison. The signal's own characteristics determine when level shifting is needed, creating a self-regulating mechanism that reduces power consumption while ensuring signal level matching is maintained when the oscillation frequency requires it.
3Productivity
If high-speed level shifter is used to maintain maximum operating speed, then frequency response is improved, but current consumption increases
Solution Approach 1:
The patent applies dynamic control to the level shifter activation based on frequency response requirements. The system continuously evaluates the oscillating output signal frequency and activates the high-speed level shifter only when the frequency exceeds the threshold, thereby maintaining optimal frequency response only when necessary and reducing current consumption during lower frequency operations.
Data Source
AI summary
An oscillator circuit powered by a source voltage generates an oscillating output signal. The oscillating output signal is level shifted and applied to a first input of a multiplexer. A second input of the multiplexer receives the oscillating output signal. The multiplexer selects one of the oscillating output signal and the level shifted oscillating output signal for output as a selected oscillating output signal in response to a select signal. A locked loop circuit generates controls a frequency of the oscillating output signal as a function of the selected oscillating output signal and a reference oscillating signal. The select signal further selects one of a reference voltage and the source voltage of the oscillator circuit as an error amplifier reference voltage for a voltage regulator circuit that generates the first power supply voltage.