Power Converter Inductance Detection Using Emulated Current Comparison
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Solution Overview
Problem
Power converters often lack prior knowledge of output inductance, necessitating a method to detect inductance without requiring additional pins on the integrated circuit die.
Innovation Solution
An inductance detection circuitry that includes an emulated current generator, comparator, inductor code counter, and variable slope resistors to adjust charge and discharge currents, enabling self-regulated inductance detection by comparing emulated and sensed currents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If prior knowledge of output inductance is used to configure the power converter, then the power converter can be properly configured for operation, but additional circuit pins or external components are required to provide this information
Solution Approach 1:
The power converter performs self-diagnosis by automatically detecting its output inductance through an emulated current generator that creates test current waveforms and compares them against expected values, eliminating the need for external pins or components to provide inductance information
Solution Approach 2:
The system creates an emulated copy of the actual inductor current using a current generator that produces test waveforms through the output inductor, allowing the controller to infer inductance values by comparing emulated versus actual current behavior without direct measurement
2Measurement precision
If inductance detection circuitry is added to the power converter, then accurate inductance detection is achieved, but the device complexity and pin count increase
Solution Approach 1:
The current generator serves multiple functions: it acts as both the power converter's output current source during normal operation and as an emulated current generator during inductance detection, eliminating the need for separate detection circuitry
Solution Approach 2:
The inductance detection functionality is merged into the existing controller and current generation circuitry, combining the emulated current generator, comparator, and counter functions within the existing power converter architecture rather than adding separate detection components
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
Enables accurate detection of output inductance in power converters, allowing for adaptive configuration without additional circuit pins, thereby enhancing operational efficiency and precision.
Implementation Method 1
an emulated current generator configured to provide an emulated current signal responsive to a charge current and a discharge current respectively charging or discharging a timing capacitor
Implementation Method 2
A comparator is configured to provide a comparator signal responsive to the emulated current signal and sensed current signal
Implementation Method 3
An inductor code counter is configured to adjust an inductor code count value responsive to the comparator signal
Data Source
AI summary
In an example, a circuit includes an emulated current generator configured to provide an emulated current signal responsive to a charge current and a discharge current. The emulated current signal can be representative of an emulated current through an output inductor. A comparator is configured to provide a comparator signal responsive to the emulated current signal and sensed current signal representative of a measure of current through the output inductor. An inductor code counter is configured to adjust an inductor code count value responsive to the comparator signal. A slope of the emulated current signal can be adjusted responsive to the inductor code count value.