Current Detection Circuit for DC/DC Converters
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Solution Overview
Problem
Existing current detection circuits for DC/DC converters require multiple components to detect currents in both input-side and output-side conduction paths, leading to increased complexity and accuracy issues due to voltage drops and temperature characteristics.
Innovation Solution
A current detection circuit that shares components between conduction paths using a configuration with OR circuits and voltage drop cancellation, allowing accurate detection of currents flowing through both paths without being affected by voltage drops or temperature changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a plurality of current detection circuits are provided for detecting currents at multiple positions, then current detection capability is improved, but the number of constituent components increases
Solution Approach 1:
The patent combines multiple current detection circuits into a single integrated circuit that can detect currents at multiple positions (input-side and output-side conduction paths) simultaneously. The circuit uses a shared operational amplifier and resistor network to process signals from multiple current sensors, eliminating the need for separate detection circuits for each position and thereby reducing the total number of components.
Solution Approach 2:
The current detection circuit is designed with multi-functionality to detect currents in both input-side and output-side conduction paths using a single circuit configuration. The circuit can selectively detect and process current signals from different paths through its operational amplifier and resistor network, making one circuit perform the function of multiple separate circuits.
2Device complexity
If diodes are used in the current detection circuit, then the number of components can be reduced, but voltage drop occurs and temperature characteristics cause threshold variation
Solution Approach 1:
The patent extracts and removes the diodes from the current detection circuit to eliminate the harmful effects of voltage drop and temperature-dependent threshold variation. By replacing the diode-based OR circuit with an operational amplifier-based circuit, the design eliminates the source of measurement errors while maintaining the ability to detect currents from multiple paths.
Solution Approach 2:
The circuit employs an operational amplifier with feedback mechanisms to maintain stable and accurate current detection thresholds that are not affected by temperature changes. The feedback loop compensates for any variations and ensures consistent detection accuracy across different operating conditions, eliminating the temperature characteristic problems associated with diodes.
Data Source
AI summary
It is an object of the present disclosure to reduce the number of constituent components and accurately detect a current. A current detection circuit detects a current flowing through a DC/DC converter. A first output unit applies, to a third signal path, a voltage that corresponds to an output from a detection sensor, which has detected a larger current, out of a first sensor and a second sensor. Furthermore, the first output unit applies, to the third signal path, a voltage obtained by reflecting a voltage drop at the transistor or the transistor that is connected to the detection sensor, in the voltage output from the detection sensor. A second output unit applies, to a fourth signal path, a voltage obtained by reflecting a voltage drop that occurs between a base and an emitter of a transistor, in the voltage applied to the third signal path.