Transformer Power Combiner With Built-In RF Filter Response
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Solution Overview
Problem
Conventional RF transmitters lack an effective filter response, making them sensitive to phase modulation and requiring off-chip band-pass filters, which increases cost and complexity.
Innovation Solution
An RF transmitter design that includes an interleaver and a distribution circuit with delay circuits and inverters to generate a filter response using a transformer, allowing for on-chip band-pass filtering and efficient power combining.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an off-chip band-pass filter is used to provide filter response, then filtering performance is improved, but device complexity and cost increase
Solution Approach 1:
The patent combines the band-pass filter function with the transformer power combiner by introducing delay circuits in the signal paths to the primary windings. This merging eliminates the need for a separate off-chip band-pass filter, reducing device complexity and cost while maintaining filtering performance through the combined transformer-filter structure.
Solution Approach 2:
The transformer is designed to perform multiple functions: power combining and band-pass filtering. By adding delay circuits that create specific phase relationships between signals from different power amplifiers, the transformer structure becomes universal, serving both as a power combiner and a filter with notches at unwanted frequencies.
2Adaptability or versatility
If phase modulation sensitivity is reduced by adding filter response, then spectral mask compliance is improved, but mismatch between power controller and PAs increases
Solution Approach 1:
The delay circuits are designed to introduce predetermined time delays that create the desired filter response characteristics before the signals are combined at the transformer. This preliminary action of adding controlled delays ensures that the filter notches occur at the correct frequencies while maintaining proper phase relationships for power combining.
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 enables a fully integrated RF transmitter with improved power combining and reduced filter complexity, achieving sufficient suppression and flexibility in noise cancellation without external components, enabling higher output power and flexible spectral mask compliance.
Implementation Method 1
a transformer having a plurality of primary windings and a secondary winding, wherein each primary winding is coupled to at least one of the PAs
Data Source
AI summary
A method for generating an amplified radio frequency (RF) signal is provided. In-phase (I) and quadrature (Q) signals are received and interleaved so as to generate a time-interleaved signal. Delayed time-interleaved signals are then generated from the time interleaved signal, and each of the delayed time-interleaved signals is amplified so as to generate a plurality of amplified signals. The amplified signals are then combined with a transformer, where the delayed time-interleaved signals are arranged to generate a filter response with the transformer.