Inductor Current Detection Circuit for Fast Response
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Solution Overview
Problem
Conventional power converters require a resistor to detect inductor current, leading to increased power consumption and inaccurate switching due to the resistor's small resistance, resulting in a slow response effect.
Innovation Solution
An inductor current detecting circuit that includes a detector circuit, differentiator circuit, current supplying circuit, and switch circuit, which alternately charge a capacitor to generate a complete waveform of the inductor current signal, allowing for accurate control of high-side and low-side switches without the need for a resistor, thereby achieving a fast response effect.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a resistor is added to detect inductor current, then current detection capability is improved, but power consumption increases
Solution Approach 1:
The patent extracts the current detection function from the traditional resistor-based approach and implements it through a dedicated detection circuit that monitors the voltage across the inductor directly. This eliminates the need for an additional series resistor, thereby removing the associated power consumption while maintaining current detection capability through voltage-to-current conversion in the detection circuit.
Solution Approach 2:
The detection circuit serves multiple functions: it detects the inductor current, generates control signals for the switches, and provides feedback for regulation. By integrating these functions into a single circuit block rather than using separate components, the patent reduces overall power consumption while maintaining comprehensive current detection and control capabilities.
2Measurement precision
If a resistor is added to detect inductor current, then current detection is enabled, but device complexity increases
Solution Approach 1:
The patent combines the current detection function with the existing control circuitry by using the same operational amplifiers and switching elements for both detection and control purposes. The detection circuit shares components with the control circuit, such as using the voltage across the inductor for both current sensing and switch control, thereby reducing overall circuit complexity despite enabling current detection.
3Use of energy by moving object
If a small resistance value is used for the resistor, then power consumption is reduced, but measurement precision deteriorates
Solution Approach 1:
The patent changes the detection parameter from direct current measurement through a small resistor to voltage measurement across the inductor. By measuring the voltage drop across the inductor and converting it to current information through the detection circuit, the system achieves accurate current detection without requiring a large resistance value, thus maintaining low power consumption while improving measurement precision.
4Measurement precision
If a resistor is added to detect inductor current, then current detection is achieved, but response speed decreases
Solution Approach 1:
The patent replaces the passive resistor-based detection mechanism with an active electronic detection circuit that uses operational amplifiers and voltage-to-current conversion. This active circuitry provides faster response speed compared to passive resistor detection, as it can rapidly amplify and process the voltage signal across the inductor to generate immediate control signals for the switches.
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 inductor current detecting circuit enables the power converter to accurately detect the complete waveform of the inductor current, allowing for precise control of the high-side and low-side switches, resulting in a fast response effect without the unnecessary power consumption of a resistor.
Implementation Method 1
The differentiator circuit is connected to the detector circuit, and configured to differentiate the high-side voltage signal to generate a first differential signal and differentiate the low-side voltage signal to generate a second differential signal
Implementation Method 2
A first terminal of the capacitor is connected to a node between the first switch component and the second switch component. A second terminal of the capacitor is connected to the second current supplying component and grounded
Data Source
AI summary
An inductor current detecting circuit is provided. A differentiator circuit differentiates a high-side voltage signal to generate a first differential signal, and differentiates a low-side voltage signal to generate a second differential signal. A first current source outputs a first charging current according to the first differential signal. A second current source outputs a second charging current according to the second differential signal. First and second terminals of a first switch are respectively connected to the first current source and a first terminal of a second switch. A second terminal of the second switch is connected to the second current source. Two terminals of a capacitor are connected to the second terminal of the first switch and the second current source respectively. The first switch and the second switch are alternately turned on to obtain a continuous waveform.