Switching Voltage Detection Circuit for Accurate High-Voltage Sensing
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Solution Overview
Problem
Existing voltage detection methods in switching power source apparatuses face accuracy issues due to voltage division and parasitic capacitance, leading to waveform rounding and detection timing delays, especially when detecting high voltages with high potential differences.
Innovation Solution
A voltage detecting circuit using a series connection of resistances and switching elements, where the voltage is divided when high and directly input when low, allowing for accurate detection without requiring high-voltage withstanding elements, and minimizing waveform rounding by controlling the switching elements based on the voltage at the detection node.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If voltage dividing circuits are used to detect high voltage, then the detection circuit can handle high voltage, but the voltage changes become smaller and detection accuracy deteriorates
Solution Approach 1:
The patent applies dynamic switching between two detection paths based on voltage level. A switching element dynamically connects the detection circuit to either the voltage dividing circuit (for high voltage) or directly to the detection node (for low voltage), optimizing both voltage withstanding capability and detection accuracy for different operating conditions
Solution Approach 2:
The patent introduces a switching element as an intermediary between the detection node and the detection circuit. This intermediary dynamically routes the detection signal through appropriate paths (voltage dividing circuit or direct connection) based on the instantaneous voltage level, resolving the contradiction between voltage handling and measurement precision
2Strength
If voltage dividing circuits are used, then high voltage can be detected, but waveform rounding occurs due to time constant circuit formation
Solution Approach 1:
The switching element dynamically selects the detection path based on voltage level, bypassing the voltage dividing circuit during low voltage periods when waveform accuracy is critical. This dynamic routing prevents the RC time constant effect from causing waveform rounding during critical detection phases
Solution Approach 2:
During low voltage periods, the circuit skips the voltage dividing circuit stage entirely and directly samples the detection node voltage through the switching element. This rushing through the intermediate stage eliminates the waveform rounding effect caused by the RC time constant
3Measurement precision
If larger voltage drop is achieved by increasing resistance, then voltage division is effective, but time constant increases and detection timing is delayed
Solution Approach 1:
The switching element dynamically adjusts the detection path based on voltage level, using the voltage dividing circuit only when necessary for high voltage protection. During low voltage detection, it uses a direct path with minimal resistance, thereby minimizing the time constant and detection timing delay while maintaining voltage division effectiveness when needed
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 high-accuracy voltage detection across a wide range without reducing detection voltage changes, reducing waveform rounding and detection timing delays, and allows for efficient operation of switching power source apparatuses.
Implementation Method 1
a voltage dividing circuit to divide the detection voltage
Implementation Method 2
minimizing time constant effects through a third resistance and switching elements
Data Source
AI summary
A voltage detecting circuit to perform voltage detection by introducing a voltage from a detection node, comprises: a first resistance, a second resistance, and a first switching element, connected in series with each other from the detection node to reference electric potential in order; and a detection circuit for performing a detection operation of a voltage by receiving input of the voltage from a node between the first resistance and the second resistance, wherein a control voltage generated on the basis of the voltage at the detection node is supplied to a control terminal of the first switching element, and the first switching element is turned on when the voltage at the detection node is large, and the first switching element is turned off when the voltage at the detection node is small.