Multiplexed Multilevel Converter Amplifier Power Loss Reduction
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Solution Overview
Problem
Existing power amplifiers for inkjet printers experience high power losses when driving capacitive loads with trapezoidal waveforms, particularly due to voltage drops across transistors during the rising and falling edges of the waveform.
Innovation Solution
A multilevel converter system with a multiplexer and control module synchronizes voltage levels between positive and negative supply rails to reduce power losses by varying the output voltage across multiple levels, using switches to connect the converter voltage to either the positive or negative supply rail during different phases of the waveform.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a basic linear power amplifier with constant voltage supply is used to drive a capacitive load with trapezoidal waveform, then the amplifier can reproduce the desired waveform, but high power losses occur due to voltage drops across transistors during rising and falling edges
Solution Approach 1:
The patent applies dynamics by making the power supply voltage variable rather than constant. The power supply voltage is dynamically adjusted to match the instantaneous output voltage level, changing from a static parameter to a dynamic one that adapts to the waveform requirements, thereby reducing power losses during transitions.
Solution Approach 2:
The patent changes the parameter of power supply voltage from a fixed constant value to a variable parameter that tracks the output voltage. This parameter change allows the amplifier to operate with minimal voltage drop across transistors during waveform transitions, directly addressing the power loss problem.
2Loss of energy
If the power supply voltage is reduced to minimize voltage drops and power losses, then energy efficiency improves, but the amplifier may not have sufficient voltage headroom to reproduce the full amplitude trapezoidal waveform
Solution Approach 1:
The power supply voltage is made dynamic and tracks the output voltage waveform. During rising and falling edges, the supply voltage matches the output voltage to minimize drops, while during the flat top portion, sufficient voltage headroom is maintained to ensure full amplitude output. This dynamic adaptation resolves the contradiction between efficiency and power capability.
Solution Approach 2:
The power supply voltage is prepared in advance to match the expected output voltage requirements. By anticipating the waveform needs and adjusting the supply voltage accordingly before critical transitions occur, the system ensures both sufficient power headroom and minimal voltage drops during actual waveform reproduction.
Data Source
AI summary
A multiplexed multilevel converter amplifier. The converter is configured to generate a converter voltage. The converter voltage varies among a plurality of voltage levels. A multiplexer is comprised of at least four switches configured to generate a positive output voltage and a negative output voltage according to a configuration of the at least four switches. The positive output voltage varies between the converter voltage and a positive supply rail and the negative output voltage varies between the converter voltage and a negative supply rail. An amplifier is supplied by the multiplexer, and the amplifier generates an output voltage that varies between the positive output voltage and the negative output voltage. A control module is configured to control the configuration of the at least four switches of the multiplexer and the plurality of voltage levels of the converter voltage, such that the converter voltage is synchronized with the output voltage.