Switching Regulator Voltage Detection Without Insulators
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Solution Overview
Problem
Conventional switching regulators require costly primary-secondary insulating parts for voltage and current detection, leading to power loss and accuracy degradation, and inefficient use of commercial power supply in image forming apparatuses.
Innovation Solution
A switching regulator with voltage waveform detection means and control means that calculate input voltage and current values without primary-secondary insulating parts, using anode voltage monitoring and pulse width analysis to accurately detect input and output values without power loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If primary-secondary insulating parts (photocoupler and current transformer) are used for voltage and current detection, then detection accuracy is improved, but device cost and complexity increase
Solution Approach 1:
The patent extracts the detection function from the primary side and implements it on the secondary side using only secondary components. The voltage detection is achieved by monitoring the voltage across the secondary rectifier diode, and current detection is achieved by measuring the voltage across the secondary smoothing condenser during capacitor discharge. This eliminates the need for primary-secondary insulating parts while maintaining detection functionality.
Solution Approach 2:
The patent creates a copy of the detection function using secondary side components that mirror the primary side detection needs. By measuring secondary voltage and current parameters and using calculation means to derive primary side values, the system replicates the detection capability without requiring direct primary side measurement components.
2Measurement precision
If current detection resistor is inserted in output power supply line for current detection, then current detection is enabled, but power loss increases
Solution Approach 1:
The patent utilizes the existing secondary smoothing condenser and its inherent discharge characteristics for current detection. During the capacitor discharge period, the voltage across the condenser is measured, and this voltage information is used by the calculation means to determine the output current. This self-service approach uses the circuit's own components and operating characteristics for detection without adding external detection elements that would cause power loss.
3Measurement precision
If current detection resistor is inserted in output power supply line, then current detection is enabled, but output voltage accuracy degrades
Solution Approach 1:
The patent uses the secondary smoothing condenser's inherent voltage characteristics during discharge for current detection. By measuring the voltage across the condenser during its natural discharge period and using calculation means to derive output current, the system achieves current detection without inserting a detection resistor that would affect output voltage accuracy.
Solution Approach 2:
The patent introduces calculation means as an intermediary that processes secondary side voltage measurements to determine primary side current values. This intermediary computation approach allows accurate current detection without physically inserting detection components into the power supply line that would degrade voltage 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
This solution eliminates the need for costly insulating parts, reduces power loss, and enables efficient use of commercial power supply, improving accuracy and reducing warming up time in image forming apparatuses.
Implementation Method 1
voltage waveform detection means for inputting a voltage applied to a rectifier diode connected in series with a secondary side of a transformer and generating a voltage signal corresponding to the voltage
Implementation Method 2
control means for calculating a voltage value inputted into a primary side of the transformer, based on a voltage value of the voltage signal generated by the voltage waveform detection means
Data Source
AI summary
A switching regulator has an input voltage detection circuit which inputs a voltage applied to a rectifier diode 7 connected in series with the secondary side of a transformer and generates a voltage signal Vvp corresponding to the voltage, and a calculation unit which calculates a voltage value Vin inputted to the primary side of the transformer based on a voltage value of the voltage signal generated by the input voltage detection circuit.