Audio Mixing Device DC Shifting Buffer Pin Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing audio mixing devices require AC coupling capacitors to prevent input buffer voltages from being pulled to abnormal voltages, which increases pin usage and device size, and complicates circuit design.
Innovation Solution
An audio mixing device with a DC shifting buffer set that couples directly between the audio codec circuit and output buffer set, allowing for the omission of AC coupling capacitors and sharing of pins, thereby avoiding abnormal voltage interference and reducing pin counts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If AC coupling capacitors are used between audio port and input buffers, then abnormal voltage interference is avoided, but device complexity and pin usage increase
Solution Approach 1:
The patent extracts and removes the AC coupling capacitor from the circuit by introducing a DC shifting buffer that actively manages DC voltage levels. The buffer shifts the DC voltage of the audio signal to a safe level before it reaches the input buffer, eliminating the need for the capacitor while preventing abnormal voltage interference.
Solution Approach 2:
The DC shifting buffer changes the DC voltage parameter of the audio signal by shifting it from one DC level to another. This parameter change allows the signal to be safely transmitted without requiring AC coupling capacitors, thereby simplifying the circuit design while maintaining protection against voltage interference.
2Reliability
If AC coupling capacitors are used to protect input buffers, then voltage interference is prevented, but device size increases
Solution Approach 1:
The patent removes the AC coupling capacitor from the circuit architecture by replacing it with a DC shifting buffer. This extraction eliminates the physical component that contributes to device size while maintaining the protective function against voltage interference through active voltage level management.
3Reliability
If separate pins are used for input and output buffers, then signal isolation is improved, but pin count increases
Solution Approach 1:
The audio port is designed with multi-functionality to serve both as an input and output interface. The DC shifting buffer enables the same pin to handle different signal directions by managing DC voltage levels, allowing the pin to function universally for both audio input and output purposes, thereby reducing the total pin count while maintaining signal isolation through proper voltage level control.
Data Source
AI summary
An output buffer set is coupled to a first pair of pins and configured to output art audio output signal to the first pair of pins. A direct current (DC) shifting buffer set is coupled between the audio codec circuit and the first pair of pins, and is directly coupled to the output buffer set and the first pair of pins. An audio port is coupled to the first pair of pins. The DC shifting buffer set is configured to receive a first audio input signal from the audio port through the first pair of pins. The audio codec circuit is configured to record the audio output signal back and mix the recorded audio output signal with a second audio input signal, or mix the first audio input signal with a third audio input signal.