Digitally Controlled Phase Interpolator With Low-Noise Oscillator Reset
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing phase interpolators are complex, power-intensive, and sensitive to noise, particularly those using synchronized oscillators, which complicates their digital control and integration.
Innovation Solution
A phase interpolator design featuring a variable phase-shifter circuit with a synchronized oscillator, a phase comparator, and a charge pump, allowing for digital control of the phase shift by varying the free oscillation frequency, thereby simplifying the structure and reducing power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a phase interpolator uses multiple initial signals for phase interpolation, then the phase interpolation function is achieved, but the structure becomes complex and power consumption increases
Solution Approach 1:
The invention divides the phase control function into two independent parts: a small number of fixed-phase initial signals (e.g., 4 signals at 0°, 90°, 180°, 270°) and a variable phase-shifter circuit that applies additional phase shift. This segmentation allows achieving arbitrary phase angles without requiring many initial signals, thus reducing structure complexity while maintaining phase interpolation capability.
Solution Approach 2:
The variable phase-shifter circuit serves multiple functions: it can adjust the phase of any initial signal independently, work with any number of initial signals (typically 2-4), and achieve continuous phase control across the full 360° range. This multi-functionality replaces the need for multiple dedicated initial signals for each phase angle.
2Adaptability or versatility
If a phase interpolator uses multiple initial signals, then phase interpolation is achieved, but the surface area increases when made in integrated form
Solution Approach 1:
By segmenting the phase control into fixed initial signals and a shared variable phase-shifter, the circuit requires fewer initial signal generators (reducing their total area) and one variable phase-shifter that serves all signals. This is more area-efficient than having multiple dedicated signal paths for each phase angle.
Solution Approach 2:
The variable phase-shifter circuit is shared among all initial signals, merging the phase adjustment function into a single circuit block that processes multiple signals. This consolidation reduces the total surface area compared to having separate phase control circuits for each initial signal.
3Device complexity
If simple delay elements are used in phase interpolator, then the structure is simplified, but the interpolator becomes highly sensitive to initial noise and manufacturing process variations
Solution Approach 1:
The invention uses a synchronized oscillator-based phase-shifter instead of simple delay elements. The oscillator is periodically reset by the reference signal, which continuously corrects drift and noise accumulation. This reset mechanism makes the system robust against manufacturing variations and noise, effectively replacing fragile delay elements with a more reliable oscillating system.
Solution Approach 2:
The synchronized oscillator operates with feedback from the reference signal through phase comparison and resetting mechanisms. This feedback continuously corrects phase deviations caused by noise or process variations, maintaining stable and reliable phase control that is insensitive to initial conditions and manufacturing tolerances.
4Reliability
If synchronized oscillators are used in phase interpolator, then noise sensitivity is reduced, but the structure becomes complex due to large number of oscillators required
Solution Approach 1:
The invention uses a small number of synchronized oscillators (typically one per initial signal, so 1-4 total) that serve multiple functions: generating the initial signal, providing phase reference, and enabling variable phase shift through controlled resetting. This multi-functionality achieves noise immunity without requiring a large number of dedicated oscillators for each function.
Solution Approach 2:
The phase control function is segmented into fixed initial signal generation (handled by a small number of synchronized oscillators) and variable phase shift (handled by a control circuit that resets the oscillators). This segmentation reduces the total number of oscillators needed compared to approaches where each phase angle requires a dedicated oscillator.
5Measurement precision
If digitally-controlled phase shifting is implemented, then phase control precision is improved, but the device complexity increases
Solution Approach 1:
The invention uses a dynamic resetting mechanism where the phase-shifter circuit is periodically reset at different points in the oscillation cycle based on digital control signals. By varying the reset timing (phase angle), precise phase control is achieved. This dynamic approach replaces complex static circuitry with a simpler time-based control mechanism.
Solution Approach 2:
The invention controls phase by changing the timing parameter (reset point) of the synchronized oscillator rather than changing physical circuit parameters. Digital control signals adjust the phase by modifying when the oscillator is reset during each cycle, providing precise phase control through parameter variation rather than complex circuit reconfiguration.
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 a simple, low-noise phase interpolation with reduced power consumption and easy digital control, enabling efficient phase shifting between input and output signals.
Implementation Method 1
a phase-shifter circuit comprising an oscillator having a variable natural frequency. The oscillator is a synchronized oscillator whose natural frequency varies according to a difference between a frequency of an input signal and a frequency of an output signal
Implementation Method 2
The phase shift of the output signal with respect to the input signal only depends on a difference between the frequency of the input signal and the natural frequency of the oscillator
Data Source
AI summary
A phase interpolator receiving a first signal having an oscillation frequency Fin and providing a second signal having said oscillation frequency and having a phase shift Δφ with respect to the first signal which depends on a third signal. The interpolator includes a variable phase-shifter receiving the first signal and providing the second signal, the phase-shifter circuit includes an oscillator having a variable natural frequency Fo controlled by a fourth signal; a phase comparator capable of receiving the first and second signals and of providing a fifth signal representative of said phase shift; and a unit capable of providing the fourth signal which depends on the third and fifth signals.