Battery Voltage Sensing Circuit for Reverse-Polarity Protection
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Solution Overview
Problem
Existing voltage detection systems in battery systems suffer from accuracy degradation due to voltage drops caused by diodes when the power supply source is inversely connected, leading to potential failure of the A/D converter.
Innovation Solution
A battery system design that includes a voltage detection means with a diode connected inversely to the power supply source, branching to a second resistor, and an A/D converter connected between first and second resistors, ensuring accurate voltage detection even with inverse connections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a diode is connected in the voltage detection circuit to protect against inverse connections, then the A/D converter is protected from failure, but voltage drop occurs due to forward voltage in the diode when properly connected, degrading voltage detection accuracy
Solution Approach 1:
The patent extracts the protective function from the main voltage detection path by using a separate diode branch. The diode is connected in parallel with the voltage detection circuit but in reverse direction, so it only conducts during inverse connections to protect the A/D converter, while leaving the main detection path unaffected during normal operation.
Solution Approach 2:
The diode acts as an intermediary protective element that intercepts inverse connection currents before they can damage the A/D converter. By positioning the diode in a specific configuration with its cathode toward the power supply source, it serves as a mediator that absorbs the harmful inverse connection effect without interfering with normal voltage detection.
2Reliability
If the diode is connected in series with the voltage detection path, then inverse connection protection is provided, but the voltage drop across the diode affects the accuracy of voltage measurement
Solution Approach 1:
The patent segments the voltage detection circuit into separate functional paths: a main detection path for accurate voltage measurement and a separate protective path with the diode. This segmentation allows the diode to provide protection without interfering with the precision of the voltage measurement in the main path.
Solution Approach 2:
The diode is connected in reverse orientation (cathode toward the power supply source) compared to the conventional forward-biased configuration. This inverted connection allows the diode to block normal voltage detection current while conducting during inverse connections, thereby providing protection without affecting normal measurement accuracy.
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 system accurately detects power supply voltage without voltage drop interference, reducing the risk of A/D converter failure, even with inverse power supply connections.
Implementation Method 1
The diode is electrically connected between the first resistor and the A/D converter, so as to be inversely connected to the power supply source and to branch to the second resistor. Even if the power supply source is inversely connected, electric current flows into the diode that is inversely connected.
Implementation Method 2
The voltage detection means includes a first resistor, a second resistor, an A/D converter, and a diode. The first resistor is connected in series to the power supply source. The second resistor is connected in series to the first resistor.
Data Source
AI summary
A battery system includes a battery unit including a plurality of battery cells, a controller electrically connected to the battery unit, a power supply source supplying electric power to the controller, and a voltage detection means disposed between the controller and the power supply source and detecting a voltage value of the power supply source. The voltage detection means includes a first resistor connected in series to the power supply source, a second resistor connected in series to the first resistor, an A/D converter electrically connected between the first resistor and the second resistor so as to branch to the second resistor, and a diode electrically connected between the first resistor and the A/D converter so as to be inversely connected to the power supply source and to branch to the second resistor.