MOS Current Detection Circuit With Low-Loss Sensing
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Solution Overview
Problem
Conventional current detection circuits in semiconductor integrated circuits face issues such as current interference and increased power loss due to the resistor used for current detection, which affects the accuracy and efficiency of current measurement, especially in high-current power MOS transistors.
Innovation Solution
A current detection circuit design that incorporates a wiring connected to the transistor, a current detection MOS transistor with its gate connected to the wiring, and a voltage detection circuit to measure the drain potential of the current detection MOS transistor, allowing for accurate current detection without influencing the current through the transistor and minimizing power loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a resistor is used for current detection in a conventional current detection circuit, then the current can be measured by measuring the voltage across the resistor, but the resistor causes power loss due to Joule heat and influences the current flowing through the transistor
Solution Approach 1:
The patent introduces a current detection MOS transistor as an intermediary element. Instead of directly measuring current through a resistor that causes power loss, the detection MOS transistor converts the current to be detected into a gate potential, which then controls another current that can be measured. This intermediary conversion process eliminates the direct power loss associated with the detection method while maintaining measurement capability.
2Loss of energy
If a resistor with low resistance value is used to minimize power loss, then a large pattern area is needed in the semiconductor integrated circuit
Solution Approach 1:
The current detection MOS transistor serves as an intermediary that eliminates the need for a large-area low-resistance resistor. By converting the detected current into a gate potential that controls another measurable current, the system achieves accurate current detection without requiring the large pattern area that would be needed for a low-resistance resistor.
3Measurement precision
If the source potential of the MOS transistor increases due to voltage across the detection resistor, then the current flowing through the MOS transistor decreases
Solution Approach 1:
The current detection MOS transistor acts as an intermediary that prevents the detection process from directly affecting the transistor current. The detection MOS transistor converts the current to be detected into a gate potential, which then modulates a separate detection current. This intermediary conversion ensures that the original transistor current flows unaffected while still enabling accurate current detection through the gate-controlled detection current.
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 design enables precise detection of current across a wide range without affecting the transistor current and reduces power loss, achieving high sensitivity and a smaller pattern area, particularly beneficial for high-current applications.
Implementation Method 1
a current detection MOS transistor having a gate connected to the wiring and allowing another current to flow through the detection MOS transistor in response to a potential of the gate applied by the wiring
Implementation Method 2
a voltage detection circuit to measure the drain potential of the current detection MOS transistor, allowing for accurate current detection
Data Source
AI summary
The invention provides a current detection circuit for a transistor, that does not influence a current flowing through the transistor, and minimizes a power loss, an increase of the pattern area and so on. A current detection circuit includes a wiring connected to a MOS transistor and forming a current path of a current of the MOS transistor, a current detection MOS transistor of which the gate is connected to the wiring, that flows a current corresponding to the potential of the gate, and a current detector detecting a current flowing through the current detection MOS transistor. The current detection circuit is configured including a load resistor connected to the current detection MOS transistor and a voltage detection circuit detecting a drain voltage of the current detection MOS transistor.