Semiconductor Regulator Circuit for Load Abnormality Detection
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Solution Overview
Problem
Existing DC power supply regulators face challenges in accurately detecting open-circuit and short-circuit abnormalities in vehicle-mounted electronic devices due to high burden on microcontrollers and power loss in sense resistors, leading to decreased detection accuracy.
Innovation Solution
A semiconductor integrated circuit with parallel transistors and current-voltage converting elements allows for independent setting of abnormality detection current values, utilizing comparators to invert outputs based on current thresholds and including thermal shutdown and delay circuits to enhance detection accuracy and prevent erroneous signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a sense resistor is provided in the input terminal to detect current for open-circuit and short-circuit detection, then abnormality detection function is achieved, but excess power is lost in the sense resistor
Solution Approach 1:
The patent extracts the current detection function from the main current path by providing a separate detection circuit with transistors Q2 and Q3 that monitor a portion of the current flowing through the voltage controlling transistor Q1. This allows abnormality detection without placing a sense resistor in the main power path, thereby eliminating the power loss issue while maintaining detection capability.
Solution Approach 2:
The patent introduces an intermediary detection circuit consisting of transistors Q2 and Q3 that act as mediators between the main current path and the detection function. These transistors provide a proportional current (1/N times the main current) to the comparators for abnormality detection, serving as an intermediary that enables detection without directly affecting the main power flow.
2Loss of energy
If the detecting resistor is set to a small value to reduce power loss, then power loss is reduced, but detecting accuracy decreases
Solution Approach 1:
The patent changes the detection parameter from direct voltage measurement across a small sense resistor to current-proportional voltage measurement through transistors. By using transistors Q2 and Q3 to provide a proportional current (1/N times the main current), the system can use larger effective detection resistance values without causing significant power loss in the main circuit, thereby improving detection accuracy while maintaining low power loss.
Solution Approach 2:
The patent creates a copy of the main current signal through transistors Q2 and Q3, which generate a proportional current (1/N times the main current) that flows through external resistors for voltage conversion. This copied signal can be measured with higher accuracy using larger resistance values without affecting the main power loss, as the detection is performed on the copied rather than the original current signal.
3Reliability
If software processing is used in a microcomputer to detect open-circuit and short-circuit, then detection function is achieved, but burden on the microcomputer becomes heavy
Solution Approach 1:
The patent implements self-service by providing hardware-based abnormality detection circuits that automatically detect open-circuit and short-circuit conditions without requiring microcomputer intervention. The comparators CMP1 and CMP2 continuously monitor the voltages and automatically generate detection signals, allowing the system to detect abnormalities autonomously and reducing the microcomputer's processing burden to merely reading the detection outputs.
Solution Approach 2:
The patent replaces the software-based detection mechanism with a hardware-based electrical detection system. By using comparators CMP1 and CMP2 to electrically compare voltages and generate detection signals, the system substitutes the mechanical/software processing approach with an automated hardware solution that performs detection continuously and instantly without burdening the microcomputer.
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 solution enables accurate detection of open-circuit and short-circuit abnormalities with reduced burden on controlling apparatus and power loss, allowing for flexible current setting and improved reliability in detecting short-circuit conditions.
Implementation Method 1
a first external terminal P1 to connect a current voltage converting element (resistor Rop) which converts current flowing in the first transistor Q2 to voltage
Implementation Method 2
a first voltage comparing circuit which compares a voltage converted by the current voltage converting element with a predetermined comparison voltage and determines which is large or small
Data Source
AI summary
A semiconductor integrated circuit for a regulator includes the following: a voltage controlling transistor; a controlling circuit; a first and second transistor; a first external terminal to connect a current voltage converting element; a first and second voltage comparing circuit which compares a converted voltage with a predetermined comparison voltage and determines which is large or small; and a first and second output terminal which externally outputs a result of comparison by the first and second voltage comparing circuit, respectively. When a current larger than a predetermined open-circuit abnormality detecting current value flows in the first transistor, output of the first voltage comparing circuit is inverted. When a current larger than a predetermined short-circuit abnormality detecting current value flows in the second transistor, output of the second voltage comparing circuit is inverted.