Passive Device Detection Using Discrete Impedance Sampling
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Solution Overview
Problem
Existing methods for identifying passive electronic devices connected to a host device are inaccurate due to self-generated currents in devices like passive headsets, leading to misidentification and incorrect gain adjustments, resulting in distorted audio experiences.
Innovation Solution
A system that increments current at discrete intervals and samples voltage to calculate impedance using a least linear squares technique, allowing for quick and accurate identification of passive devices without disrupting the user experience, and adjusts gain settings accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If impedance measurement is performed by supplying current and sampling voltage, then device identification can be achieved, but self-generated current in passive devices causes measurement inaccuracy
Solution Approach 1:
The patent applies periodic action by switching the current supply in discrete intervals rather than continuously. The host device supplies current at specific time intervals and measures voltage responses during these intervals, allowing the system to distinguish between current generated by the host and self-generated current by the passive device. This periodic measurement approach resolves the measurement inaccuracy caused by self-generated current while maintaining reliable device identification.
2Productivity
If continuous current supply is used for impedance measurement, then measurement can be performed, but audible noise is generated during measurement
Solution Approach 1:
The patent uses periodic action with discrete time intervals to supply current and measure voltage, replacing continuous current supply. By measuring voltage at specific discrete intervals rather than continuously, the system achieves measurement functionality without generating audible noise, as the current changes are localized to specific time windows rather than being continuous.
Solution Approach 2:
The patent applies the skipping principle by rapidly transitioning between current supply intervals, effectively rushing through the measurement process in discrete steps. The host device quickly supplies current for a brief interval, measures the voltage response, then pauses, creating a rapid measurement cycle that completes the identification process without sustained current supply that would generate audible noise.
3Ease of operation
If multiple gain adjustments are implemented for different headset types, then user experience is optimized, but device complexity increases
Solution Approach 1:
The patent applies preliminary action by performing device identification and impedance measurement before the actual audio playback begins. The host device measures the impedance of the connected passive device in advance, determines the appropriate gain settings, and configures them beforehand. This preliminary identification and configuration action eliminates the need for complex real-time gain adjustment logic during audio playback, reducing operational complexity while maintaining optimized user experience.
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
Ensures high accuracy and speed in passive device identification, preventing audible noise during measurement and optimizing audio settings for the connected device.
Implementation Method 1
measuring device impedance is one way to determine what type of passive electronic device is connected to a host. In some cases, impedance can be measured in a passive electronic device by supplying current, sampling a voltage, and solving for the impedance using Ohm's law.
Implementation Method 2
passive headsets may include one or more coils positioned in the field of a magnet that can self-induce a current when ambient sound in the room causes movement of the coils
Data Source
AI summary
A system for passive device identification includes a passive device communicatively coupled to a processing device. The processing device includes a passive device identifier configured to a current supplied to the passive electronic device at discrete intervals and to sample a voltage of the passive electronic device at each one of the discrete intervals to generate a dataset of current-voltage pairs. The passive define identifier is further configured to identify the passive electronic device based on the generated dataset.