Current Detection Circuit Drain Voltage Amplification
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Solution Overview
Problem
High-speed switching in current detection circuits for DCDC converters necessitates expensive operational amplifiers, leading to increased manufacturing costs.
Innovation Solution
The current detection circuit design amplifies the potential difference between the drain voltage of the drive transistor and the sense transistor, rather than the source voltage, allowing for the use of low withstand voltage operational amplifiers and reducing the need for high-speed operation, thereby suppressing manufacturing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the operational amplifier amplifies the potential difference between source voltages of the drive transistor and sense transistor, then accurate current detection is achieved, but high-speed operational amplifiers are required for high switching frequencies, increasing manufacturing cost
Solution Approach 1:
The patent changes the voltage parameter being amplified from source voltage difference to drain voltage difference. By amplifying the potential difference between drain voltages instead of source voltages, the circuit achieves accurate current detection without requiring high-speed operational amplifiers, thus reducing manufacturing cost while maintaining detection accuracy.
2Speed
If the operational amplifier performs high-speed operation to handle high switching frequencies, then accurate current detection during switching is achieved, but expensive operational amplifiers are necessary, increasing manufacturing cost
Solution Approach 1:
The patent changes which voltage parameter is amplified by the operational amplifier. Instead of amplifying source voltage differences that require high-speed response to high-frequency switching, the circuit amplifies drain voltage differences, which can be processed by lower-speed, less expensive operational amplifiers while still achieving accurate current detection.
3Reliability
If the circuit uses the conventional configuration with source voltage amplification, then current detection functionality is achieved, but the operational amplifier must be expensive and high-speed, worsening manufacturing cost
Solution Approach 1:
The patent modifies the conventional current detection configuration by changing the voltage measurement point from source terminals to drain terminals. This parameter change allows the operational amplifier to process slower-varying signals, enabling the use of lower-cost operational amplifiers while maintaining reliable current detection functionality.
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
This approach enables accurate current detection without the requirement for expensive high-speed operational amplifiers, maintaining operational efficiency and reducing manufacturing costs while supporting high-speed switching operations.
Implementation Method 1
a first operational amplifier which amplifies a potential difference between a drain voltage of the first drive transistor and a drain voltage of the first sense transistor
Data Source
AI summary
According to an embodiment, a current detection circuit includes a transistor, an operational amplifier, and a transistor. In the transistor, the source and the gate are coupled to the source and the gate of a transistor which is provided on a high side of a drive circuit. The operational amplifier amplifies a potential difference between a drain voltage of the transistor and a drain voltage of the transistor. The transistor is provided over a current path through which a current flowing to the transistor flows, and which has the gate to which an output voltage of the operational amplifier is supplied. A value of the current flowing through the transistor is detected based on a value of the current flowing through the transistor.