Gate-Boosted Amplifier Rail Control for Higher Output Swing
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Solution Overview
Problem
Conventional class H controlled amplifiers have limited overdrive voltage due to class H control preventing gate boost voltage from exceeding supply voltage rails, restricting output voltage swing and amplifier efficiency.
Innovation Solution
An electronic system with an on-chip charge pump generates a gate boost voltage to increase the overdrive voltage of on-chip FETs, allowing the output voltage to swing closer to the supply voltage rails, and a class H controller varies the supply voltage rails based on output voltage swings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If class H control is used to vary supply voltage rails, then amplifier efficiency is improved, but gate boost voltage is limited and cannot exceed supply voltage rails
Solution Approach 1:
The patent separates the charge pump circuit from the power supply circuit, allowing the charge pump to generate gate boost voltages independently of the supply voltage rails. This segmentation enables the gate boost voltage to exceed the supply voltage without compromising amplifier efficiency, as the two functions are no longer constrained by the same voltage limitations.
Solution Approach 2:
The patent introduces an on-chip charge pump as an intermediary device between the power supply and the amplifier output stage. This charge pump acts as a mediator that can generate higher voltages than the supply rails to provide adequate gate drive voltage, while the amplifier itself continues to operate efficiently with the original supply voltage rails.
2Reliability
If thicker gate oxide layers are used for higher power applications, then device reliability is improved, but overdrive voltage decreases
Solution Approach 1:
The patent changes the voltage parameter by introducing a charge pump that generates gate boost voltages exceeding the supply voltage rails. This parameter change compensates for the reduced overdrive voltage caused by thicker gate oxide layers, allowing the amplifier to maintain both high power capability and device reliability.
3Use of energy by moving object
If supply voltage rails are lowered to increase efficiency, then power delivery is improved, but output voltage swing is restricted
Solution Approach 1:
The patent segments the voltage generation functions by using a dedicated on-chip charge pump separate from the main power supply. This allows the power supply to operate at lower voltages for efficiency while the charge pump provides the necessary voltage headroom for adequate output swing through gate boosting.
Solution Approach 2:
The patent replaces the mechanical constraint of fixed supply voltage rails with an electrical solution using a charge pump. This substitution allows dynamic generation of higher gate voltages from lower supply voltages, enabling both efficient power delivery and adequate output voltage swing.
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 enhances amplifier efficiency by allowing the output voltage to approach the supply voltage rails more closely, accommodating lower supply voltage rail divisions and increasing power delivery to the load.
Implementation Method 1
a first on-chip charge pump, coupled to the first on-chip FET, to generate a gate boost voltage to boost a gate voltage of the gate of the first on-chip FET
Data Source
AI summary
In at least one embodiment, an electronic system includes an amplifier having an on-chip charge pump to provide a gate boost voltage to boost a gate voltage of at least one on-chip field effect transistor (FET) of an output stage of an amplifier. In at least one embodiment, the gate boost voltage boosts the gate voltage higher than the supply voltage rail to increase an overdrive voltage of the on-chip FET. In at least one embodiment, the gate boost voltage boosts the DC bias of an input signal and, thus, generation of gate boost voltage by the on-chip charge pump is signal-independent, i.e. independent of the input signal. Increasing the overdrive voltage increases the efficiency of the amplifier by decreasing the difference between the maximum swing of the output voltage and the voltage supply rails of the at least one on-chip FET relative to conventional designs.