Power Converter Negative Current Detection Mechanism
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Solution Overview
Problem
Conventional power converters require recalibration of on-resistance when replacing low-side switches, affecting current detection and voltage calculation, which is inefficient and requires additional pin resources.
Innovation Solution
A power converter with a negative current detection mechanism using a high-side switch, low-side switch, inductor, capacitors, resistors, and a negative current detector circuit that includes operational amplifiers and transistors, allowing real-time detection of negative current without additional pins, enabling adaptive switching to maintain current thresholds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional detector circuit uses on-resistance calculation method, then voltage value can be calculated based on detected current, but the circuit requires recalibration when low-side switch is replaced
Solution Approach 1:
The patent replaces the conventional on-resistance calculation method with a negative current detection mechanism using an operational amplifier circuit. This substitution eliminates the need for recalibration when switches are replaced, as the new circuit directly detects negative current flow through the inductor without relying on fixed on-resistance values of specific switch components.
2Measurement precision
If conventional detector circuit is used, then current detection is possible, but additional pin resources are required for recalibration
Solution Approach 1:
The operational amplifier-based negative current detector circuit serves multiple functions: it detects negative current flow, determines when current drops below thresholds, and triggers adaptive switching operations. This multi-functionality is achieved within the existing pin structure without requiring additional calibration pins, thereby reducing device complexity while maintaining measurement precision.
3Measurement precision
If on-resistance recalibration is performed, then accurate voltage calculation is restored, but system efficiency decreases due to additional operations
Solution Approach 1:
The negative current detector circuit automatically detects when inductor current becomes negative or drops below the threshold, and autonomously triggers the controller to adjust switching operations. This self-service mechanism eliminates the need for external recalibration operations, maintaining voltage calculation accuracy while improving system efficiency by removing unnecessary manual intervention steps.
4Reliability
If negative current detection is implemented, then adaptive switching can prevent current drops below thresholds, but circuit complexity increases
Solution Approach 1:
The operational amplifier circuit acts as an intermediary between the inductor current and the controller. It monitors the current flow through the sense resistor and generates appropriate trigger signals when negative current or threshold violations occur, thereby maintaining reliability while keeping the overall system architecture manageable through a dedicated intermediate detection stage.
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 real-time detection of negative current and adaptive switching to prevent current drops below thresholds, maintaining performance even with new low-side switches without recalibrating on-resistance, thus improving efficiency and flexibility.
Implementation Method 1
The negative current detector circuit includes a first operational amplifier, a first transistor and the second transistor. A non-inverting input terminal of the first operational amplifier is connected to a second terminal of the sense resistor. An inverting input terminal of the first operational amplifier is connected to a first terminal of the first capacitor.
Implementation Method 2
A control terminal of the first transistor is connected to an output terminal of the first operational amplifier. A control terminal of the second transistor is connected to the output terminal of the first operational amplifier.
Data Source
AI summary
A power converter with a negative current detection mechanism is provided. A negative current detecting circuit includes a first operational amplifier, a first transistor and a second transistor. A non-inverting input terminal of the first operational amplifier is connected to a second terminal of a sense resistor. An inverting input terminal of the first operational amplifier is connected to a first terminal of a first capacitor. Control terminals of the first and second transistors are connected to an output terminal of the first operational amplifier. A first terminal of the first transistor is connected to the second terminal of the sense resistor. A second terminal of the first transistor is grounded. A first terminal of the second transistor is connected to the inverting input terminal of the first operational amplifier and the first terminal of the first transistor. A second terminal of the second transistor is grounded.