Class-D Power Stage Gate Driver With Current Multiplier
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Solution Overview
Problem
Conventional driver devices for class-D amplifiers require high capacitance and bootstrap capacitors or charge pumps, leading to increased component costs and complexity.
Innovation Solution
A driver circuit for class-D amplifiers that includes serially connected transistor devices with a current multiplier, which produces a larger output current, reducing the capacitance requirements and component costs by using a voltage generator and current multiplier configured between the gate and source/drain terminals of a power transistor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If conventional driver devices use bootstrap capacitors or charge pumps to generate reference voltage, then the reference voltage can be produced, but the component cost and device complexity increase substantially
Solution Approach 1:
The patent extracts and eliminates the bootstrap capacitor and charge pump components from the conventional driver device architecture. By removing these external components and integrating their functionality directly into the driver circuit using the current multiplier approach, the design achieves reference voltage generation without the associated complexity and cost.
Solution Approach 2:
The patent merges the reference voltage generation function with the driver circuit itself by implementing a current multiplier that directly generates the required voltage levels. This integration combines multiple functions (current multiplication and voltage generation) into a single circuit block, eliminating the need for separate bootstrap capacitors or charge pumps.
2Power
If conventional driver devices use bootstrap capacitors or charge pumps, then reference voltage can be generated, but the capacitance requirements become stringent
Solution Approach 1:
The patent changes the fundamental operating parameters of the driver circuit by using a current multiplier with a current multiplication factor greater than one. This parameter change allows the circuit to generate the necessary voltage levels with significantly reduced capacitance requirements, as the current multiplication compensates for the reduced capacitive storage capability.
3Quantity of substance
If the current multiplier produces a larger output current, then the capacitance requirement can be relaxed, but the device complexity increases
Solution Approach 1:
The current multiplier circuit performs multiple functions simultaneously: it multiplies the input current, generates the reference voltage, and drives the power stage transistors. This multi-functionality reduces the need for separate components and simplifies the overall device architecture despite the sophisticated current multiplication mechanism.
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 proposed solution reduces the capacitance requirements for the driver devices, thereby lowering the component costs and improving the efficiency of the class-D amplifier power stage.
Implementation Method 1
The current multiplier includes multiple current mirrors
Data Source
AI summary
Embodiments of a driver circuit for a power stage of a class-D amplifier and a class-D amplifier are described. In one embodiment, a driver circuit for a power stage of a class-D amplifier includes serially connected transistor devices connected to a gate terminal of a power transistor of the power stage of the class-D amplifier, a voltage generator connected between a gate terminal of a first transistor device of the serially connected transistor devices and a source terminal of the power transistor, and a current multiplier connected between the gate terminal of the power transistor and one of a source terminal and a drain terminal of the first transistor device. The current multiplier is configured to produce an output current that is proportional to a current at the one of the source terminal and the drain terminal of the first transistor device.