Multi-Channel Amplifier Output Regulation With Phase-Shifted Switching
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Solution Overview
Problem
Conventional amplification systems, such as those using Class-D amplifiers, face challenges in efficiently regulating output signals across multiple channels, leading to large ripples in power supply and electromagnetic interference issues due to synchronized power stage switching.
Innovation Solution
The system introduces phase-shifted ramp signals across channels, with each channel receiving a ramp signal corresponding to a specific phase, and incorporates loop filters and comparators to process input signals and generate output signals based on these phases, while also employing periodic jittering or pseudo-random jittering in the oscillation frequency to reduce interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If synchronized power stage switching is used across multiple channels, then device complexity is reduced, but power supply ripples and electromagnetic interference increase
Solution Approach 1:
The patent applies periodic action by introducing phase-shifted ramp signals to different channels at different phases (e.g., 0°, 120°, 240° for three-phase systems). This causes the power stages in each channel to switch at different times within the switching period, distributing the switching events throughout the cycle rather than simultaneously. This temporal distribution reduces the cumulative effect of switching transients on the power supply and electromagnetic interference, while maintaining the simplicity of synchronized control architecture.
Solution Approach 2:
The patent implements dynamics by making the switching timing of each channel dynamic and phase-dependent. Instead of fixed simultaneous switching, each channel's power stage switching is dynamically adjusted according to its assigned phase of the ramp signal. This dynamic phase distribution allows the system to maintain simple control logic while achieving asynchronous switching effects that reduce harmful electromagnetic interference and power supply ripples.
2Object-generated harmful factors
If phase-shifted ramp signals are used across channels, then power supply ripples and electromagnetic interference are reduced, but device complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the multi-channel system into independent control segments, where each channel receives its own phase-shifted ramp signal and has independent loop filter and comparator circuits. This segmentation allows each channel to operate with simplified individual control logic while the collective system benefits from phase-distributed switching. The segmentation isolates the complexity of phase management to the signal generation stage while keeping channel-level control simple.
3Object-generated harmful factors
If periodic jittering is applied to oscillation frequency, then electromagnetic interference is reduced, but output signal regulation becomes more difficult
Solution Approach 1:
The patent applies parameter changes by periodically varying the oscillation frequency through jittering, which shifts the switching frequency away from fixed values that may coincide with resonant frequencies or create concentrated electromagnetic interference. The frequency parameter is dynamically adjusted within a controlled range to spread spectral energy and reduce peak interference. Simultaneously, the loop filter is designed to maintain regulation precision by filtering out the frequency variations and maintaining stable average output characteristics.
Data Source
AI summary
Systems and methods are provided for amplifying multiple input signals to generate multiple output signals. An example system includes: a first channel configured to receive a first input signal and a second input signal and generate a first output signal and a second output signal based at least in part on the first input signal and the second input signal; and a second channel configured to receive a third input signal and a fourth input signal and generate a third output signal and a fourth output signal based at least in part on the third input signal and the fourth input signal. A first differential signal is equal to the first input signal minus the second input signal. A second differential signal is equal to the third input signal minus the fourth input signal. The first output signal corresponds to a first phase.