Multi-Stage Pulse Shaping Network for RF Supply Modulation
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Solution Overview
Problem
RF transmitters face a trade-off between energy efficiency and linearity, making it challenging to transmit data carrying RF signals with both high efficiency and high linearity, especially in mobile devices where RF amplifiers are physically distant from the power management circuit.
Innovation Solution
A multi-stage pulse shaping network (PSN) with a first stage coupled to a power management circuit and multiple second stages, each coupled to an RF amplifier, along with a reconfigurable filter circuit that uses parasitic elements and switches to provide various filtering characteristics, allowing for control of receive band noise and out-of-band emissions while maintaining linearity and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a single-stage pulse shaping network is used, then the circuit complexity is low, but the control of receive band noise and out of band emissions is insufficient
Solution Approach 1:
The pulse shaping network is divided into multiple stages, where each stage performs specific filtering functions. The first stage handles initial pulse shaping while subsequent stages provide additional filtering for receive band noise and out of band emissions control, allowing complex filtering to be achieved through modular decomposition
Solution Approach 2:
The patent extends the pulse shaping network from a single stage to multiple stages in the frequency domain, adding dimensional complexity to the filtering capability. This multi-stage arrangement enables control of multiple frequency bands simultaneously, addressing both receive band noise and out of band emissions
2Adaptability or versatility
If the RF amplifier is placed physically distant from the power management circuit, then the mobile device form factor is improved, but the control of supply modulation transmitters deteriorates
Solution Approach 1:
The pulse shaping network is segmented into multiple stages that can be distributed across different physical locations. The first stage can be placed near the power management circuit while subsequent stages are placed near the RF amplifier, enabling physical separation while maintaining control integrity
Solution Approach 2:
The multi-stage pulse shaping network acts as an intermediary between the power management circuit and the RF amplifier. Even when physically distant, the network maintains control by providing intermediate filtering and shaping functions that ensure proper supply modulation transmitter operation
3Manufacturing precision
If high linearity is achieved, then the signal quality is improved, but the energy efficiency deteriorates
Solution Approach 1:
The pulse shaping network performs preliminary filtering and shaping of the supply voltage before it reaches the RF amplifier. By pre-conditioning the power supply signal, the system achieves better linearity in the amplifier output without requiring the amplifier to operate in a highly linear but inefficient mode, thus improving energy efficiency while maintaining signal quality
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
This solution enables the concurrent achievement of high efficiency and high linearity in RF transmitters, accommodating multiple RF amplifiers in a cost-effective mobile device form factor by filtering out undesirable frequency components and dynamically selecting filter characteristics based on load impedance.
Implementation Method 1
the first PSN stage comprises a passive LC filter
Implementation Method 2
first PSN stage may be implemented utilizing parasitic inductance and/or capacitive and/or resistive characteristics
Implementation Method 3
first PSN stage may be implemented utilizing parasitic inductance and/or capacitive and/or resistive characteristics
Implementation Method 4
at least one of the two or more signal paths including a switch element configured to selectively couple at least one of the at least one reactive elements between a reference potential and at least one of the first and second terminals
Data Source
AI summary
In a discrete supply modulation system, a circuit includes a multi-stage pulse shaping network (PSN) having a first PSN stage having an input configured to receive variable bias supply signals from a power management circuit (PMC) and having an output coupled to one or more second PSN stages with each of the one or more second PSN stages having an output configured to be coupled to a supply (or bias) terminal of a respective one of one or more radio frequency amplifiers. Such an arrangement is suitable for use with transmit systems in mobile handsets operating in accordance with 5th generation (5G) communications and other connectivity protocols such as 802.11 a/b/g/n/ac/ax/ad/ay and is suitable for use with multiple simultaneous transmit systems including multiple-input, multiple-output (MIMO), uplink carrier aggregation (ULCA) and beamforming.