Switchable Flip-Flop Frequency Divider for Multi-Band RF Circuits
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Solution Overview
Problem
Conventional RF circuits supporting multi-band signals face challenges in reducing chip surface area, power consumption, and out-band phase noise, particularly when generating frequency signals for different bands.
Innovation Solution
A frequency divider and RF circuit utilizing a plurality of flip-flops with switch units that adjust signal transfer paths based on a control signal to divide frequencies by different multiples, allowing for efficient reduction of out-band phase noise and power consumption, while maintaining a compact chip design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple frequency dividers are used to support multi-band signals, then frequency division capability is improved, but chip surface area and device complexity increase
Solution Approach 1:
The patent implements a universal frequency divider that can perform multiple frequency division ratios (2, 3, 4, 5, 6, 7, 8) using a single circuit structure with 8 flip-flops. The control signal selectively activates different numbers of flip-flops in series to achieve various division ratios, eliminating the need for multiple separate frequency divider circuits and thereby reducing chip surface area while maintaining multi-band signal support capability.
2Adaptability or versatility
If multiple frequency dividers are used to support multi-band signals, then frequency division capability is improved, but device complexity increases
Solution Approach 1:
The patent implements a universal frequency divider that can perform multiple frequency division ratios (2, 3, 4, 5, 6, 7, 8) using a single circuit structure with 8 flip-flops. The control signal selectively activates different numbers of flip-flops in series to achieve various division ratios, eliminating the need for multiple separate frequency divider circuits and thereby reducing chip surface area while maintaining multi-band signal support capability.
3Object-affected harmful factors
If serial frequency division is performed multiple times, then out-band phase noise is reduced, but power consumption increases
Solution Approach 1:
The patent applies partial action by selectively activating only the necessary number of flip-flops based on the required frequency division ratio. For example, to achieve division by 2, only one flip-flop is activated; for division by 4, two flip-flops are activated. This partial activation approach maintains the phase noise reduction benefit of serial division while minimizing power consumption by keeping unused flip-flops in a low-power state.
Data Source
AI summary
A flip-flop, and a frequency divider and an RF circuit using the flip-flop. The frequency divider, which receives a first signal and generates a second signal by dividing a frequency of the first signal, including a plurality of flip-flops that each latch and output a signal based on the first signal; and at least one switch unit that is switched in response to a control signal to modify a signal transfer path between the plurality of the flip-flops, wherein a different number of flip-flops are activated in response to each first and second status of the control signal so that the frequency of the first signal is divided by different multiples.