Configurable Frequency Divider Using MOSFET Switches for Multi-Band RF
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Solution Overview
Problem
Mobile devices in wireless communication systems face challenges with limited battery life due to current consumption by oscillators and the need to minimize circuit component area, particularly in achieving different frequency bands and avoiding frequency pulling effects among VCOs.
Innovation Solution
A frequency divider with a configurable dividing ratio using clocked and non-clocked MOSFET switches to select among multiple dividing ratios, allowing for efficient frequency division and reducing current consumption and circuit area by reusing transistors and inverters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple oscillators are used to operate different circuits at different frequencies, then frequency versatility is improved, but current consumption increases and battery life decreases
Solution Approach 1:
The patent implements a single oscillator that can generate multiple frequency outputs through a configurable frequency divider. The frequency divider can be programmed to divide the oscillator output by different factors (N, N+1, N+2), allowing one oscillator to serve multiple frequency requirements that would traditionally require separate oscillators, thereby reducing current consumption while maintaining frequency versatility.
2Adaptability or versatility
If multiple oscillators are used to operate different circuits at different frequencies, then frequency versatility is improved, but the area occupied by circuit components increases
Solution Approach 1:
The frequency divider circuit is designed to provide multiple dividing ratios using a unified structure. By sharing common circuit components (such as the phase detector, charge pump, and voltage-controlled oscillator) across different frequency division modes, the patent reduces the total area required compared to having separate oscillator circuits for each frequency requirement.
3Adaptability or versatility
If multiple VCOs are used to achieve different frequency bands, then frequency band coverage is improved, but frequency pulling effects between VCOs occur
Solution Approach 1:
The patent employs a single voltage-controlled oscillator whose output frequency is adjusted by changing the division ratio of the frequency divider rather than using multiple VCOs. This eliminates frequency pulling effects between VCOs because there is only one VCO. The frequency band coverage is achieved by programmatically changing the division ratio to match different operating bands.
4Device complexity
If a frequency divider with fixed dividing ratio is used, then circuit simplicity is maintained, but adaptability to different frequency bands is reduced
Solution Approach 1:
The frequency divider incorporates a programmable division ratio mechanism that can be dynamically adjusted based on the required frequency band. The division ratio is controlled by a programmable logic unit that receives band selection signals and configures the divider accordingly. This dynamic reconfigurability allows the circuit to adapt to different frequency bands while maintaining a unified hardware structure, balancing complexity and versatility.
Data Source
AI summary
A method for dividing the frequency of a signal using a configurable dividing ratio is disclosed. An input signal with a first frequency is received at clocked switches in a frequency divider with a configurable dividing ratio. Non-clocked switches inside the frequency divider are operated to select one of multiple dividing ratios. An output signal is output with a second frequency that is the first frequency divided by the selected dividing ratio.