Charge-Pump Switching Amplifier for Limited-Supply Output Boost
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Solution Overview
Problem
Existing switching amplifiers face challenges in increasing output power while maintaining efficiency due to limitations in power supply voltage and increased power consumption, particularly in class D and class E amplifiers, leading to issues like parasitic resistance and impedance changes affecting reliability.
Innovation Solution
A switching amplifier design incorporating complementary switches and a capacitance connected to a power supply, with impedance elements and a power combiner, allows for controlled boosting and step-down of output voltage using stored electric charge, enhancing power efficiency and output power without increasing current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the output current is increased to increase output power when power supply voltage is limited, then the output power increases, but the power loss increases due to parasitic resistance
Solution Approach 1:
The invention changes the voltage parameter by introducing a charge pump circuit that generates a boosted voltage (e.g., doubled or quadrupled power supply voltage). This allows the amplifier to operate at higher output power with reduced current, thereby reducing I²R losses in parasitic resistances while maintaining the required power output level.
2Power
If the load impedance is lowered to increase output power, then the output power increases, but the insertion loss increases and the number of matching components increases
Solution Approach 1:
The invention transforms the impedance parameter by using a charge pump to generate a boosted voltage that effectively increases the output voltage swing. This allows the amplifier to drive the same load with higher voltage and lower current, reducing the need for aggressive impedance matching and minimizing insertion losses in matching networks.
3Power
If a charge pump circuit is used to control voltage boosting, then the boosting amount can be controlled to be constant, but the area and power consumption increase due to additional circuit elements
Solution Approach 1:
The invention makes the switching elements and capacitances perform multiple functions: they serve both as the core amplifier switching components and as the charge pump circuit elements. The same switches and capacitances that constitute the amplifier also generate the boosted voltage, eliminating the need for separate dedicated charge pump components and reducing overall circuit area.
Solution Approach 2:
The invention merges the amplifier circuit and charge pump circuit into a single integrated structure. The switching elements and capacitances are shared between both functions, combining what were previously separate circuits into one unified design that reduces component count and circuit area while maintaining controlled voltage boosting.
4Power
If a class D amplifier with negative and positive power supply is used to control boosting, then the boosting amount is controlled to be constant, but the area and power consumption increase due to the power supply circuit
Solution Approach 1:
The invention enables the amplifier to generate its own boosted voltage supply internally through the charge pump mechanism using its own switching elements and capacitances. This self-service approach eliminates the need for external negative voltage generation circuits, reducing both the area occupied by power supply components and the power consumption associated with maintaining separate positive and negative voltage rails.
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 design achieves a quadrupled output power with maintained efficiency and reduced power consumption, while minimizing chip area and power loss, by generating a rectangular voltage waveform with controlled amplitude.
Implementation Method 1
a capacitance having both ends connected to output ends of the first and second switches, the capacitance receiving power from a power supply
Data Source
AI summary
The present invention increases the output voltage of a switching amplifier in a situation where the power supply voltage is limited. The switching amplifier includes first and second switches that are turned on and off in a complementary manner, and a capacitance, both ends of which serve as inputs to a power combiner. Both ends of the capacitance are connected to output ends of the first and second switches. The capacitance is supplied with power along with the operation of the first and second switches. As a result, an electric charge in the capacitance is used as a charge pump, and is used alternatingly for boosting or stepping down the output voltage depending on the operation frequency of the switching amplifier, thereby generating a rectangular voltage with a controlled wave height.