Ring-Based Multi-Push VCO for Wide Tuning and Compact Layout
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Solution Overview
Problem
Existing voltage-controlled oscillators (VCOs) have limited frequency tuning range and are bulky due to their LC tank architecture, making them difficult to implement and constrain frequency control in multi-push VCO designs.
Innovation Solution
A ring-based multi-push VCO is developed using a plurality of delay cells, buffer amplifiers, and a bias unit, where each delay cell comprises NMOS and PMOS transistors and a thin-film microstrip line to equalize phase, allowing for increased frequency multiplication and enhanced output power without using inductors, thereby reducing circuit size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If LC tank architecture is used for VCO, then frequency tuning range is limited and circuit area is large, but frequency control capability is constrained
Solution Approach 1:
The VCO is divided into multiple delay cells (first, second, third delay cells) connected in series to form a ring oscillator structure. Each delay cell contributes to the overall frequency determination, enabling frequency multiplication while maintaining a compact design without requiring large LC tanks.
Solution Approach 2:
The traditional LC tank (inductor-capacitor resonant circuit) is replaced with a ring-based delay cell architecture. This substitution eliminates the need for bulky inductors while achieving frequency control through delay element propagation, thereby reducing circuit area while expanding frequency tuning capabilities.
2Productivity
If multi-push VCO architecture is used, then frequency multiplication is achieved, but frequency tuning range remains limited due to LC tank constraints
Solution Approach 1:
The delay cells are designed with controllable delay characteristics that can be dynamically adjusted. By varying the delay amount in each cell through control voltages applied to the delay elements, the overall oscillation frequency can be tuned across a wider range while maintaining the frequency multiplication effect of the multi-push architecture.
Solution Approach 2:
The invention changes the operating parameters of the delay cells by applying different control voltages to the delay elements. This allows dynamic adjustment of the delay time in each cell, thereby expanding the frequency tuning range while preserving the frequency multiplication capability inherent in the multi-push configuration.
3Adaptability or versatility
If ring-based VCO is used, then frequency tuning range is wider, but frequency control is still constrained
Solution Approach 1:
The ring oscillator structure provides natural feedback through the series connection of delay cells, where the output of the last delay cell feeds back to the input of the first delay cell. This feedback mechanism enables stable frequency control while maintaining a wide tuning range, as the oscillation frequency is determined by the total delay around the loop which can be continuously adjusted.
Data Source
AI summary
A ring-based multi-push voltage-controlled oscillator (VCO) generates a multi-push output signal using a control voltage. The ring-based multi-push VCO includes a plurality of delay cells, a plurality of buffer amplifiers, and a bias unit. The delay cells connect each other in sequence to form a ring structure, and each delay cell connects with the respective buffer amplifier. The bias unit connects with the buffer amplifiers to output the multi-push output signal. The control voltage supplied to the delay cells is utilized to control the frequency of the multi-push output signal, and the ring structure formed by the delay cells is to multiply the frequency of the multi-push output signal to increase the frequency tuning range.