Switching Power Supply IC Operation Condition Setting via External Resistor
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Solution Overview
Problem
Existing switching power supply devices face challenges in setting operation conditions without adding dedicated terminals to the power supply control IC, leading to increased costs and design complexities, especially when trying to accommodate various electronic instrument specifications.
Innovation Solution
A switching power supply device with a condition setting circuit that adjusts the resistance value of a resistor connected to the OUT or IS terminal during the initialization period, allowing for the setting of operation conditions without additional terminals, using a drive circuit to control the switching element and a control circuit to determine the operation condition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a dedicated terminal for setting operation conditions is added to the power supply control IC, then the ease of operation is improved, but the device complexity increases
Solution Approach 1:
The patent applies multi-functionality by enabling existing terminals (OUT terminal or IS terminal) to serve dual purposes: their original functions plus operation condition setting function. The condition setting circuit utilizes the existing terminal structure to detect resistance values during initialization period, allowing operation mode selection without adding dedicated terminals. This resolves the contradiction by making existing components perform multiple functions.
Solution Approach 2:
The system performs self-service through automatic operation condition setting based on externally connected resistance values. During the initialization period, the condition setting circuit automatically detects the resistance value connected to the terminal and autonomously configures the operation mode without requiring manual intervention or additional control terminals. This eliminates the need for dedicated setting terminals while maintaining ease of operation.
2Adaptability or versatility
If the lineup of power supply control IC is increased to accommodate various electronic instrument specifications, then the adaptability is improved, but the manufacturing precision worsens due to increased cost
Solution Approach 1:
The patent implements parameter changes by allowing a single power supply control IC to accommodate multiple operation conditions through externally connected resistance values. The condition setting circuit detects different resistance values and automatically configures corresponding operation parameters (such as switching frequency, current limit, or mode selection). This enables one IC model to replace multiple specialized ICs, improving adaptability while maintaining consistent manufacturing standards and reducing costs.
3Device complexity
If a multi-functional capacitor is used for setting operation conditions during initialization period, then the device complexity is reduced, but the reliability worsens due to affecting normal operations
Solution Approach 1:
The patent extracts the operation condition setting function from the normal operational components. Instead of using multi-functional capacitors that interfere with normal operations, the invention separates the setting function by utilizing externally connected resistance values detected during the initialization period. The condition setting circuit reads the resistance value and configures operation modes before normal operation begins, then the capacitor returns to its original decoupling function without interference. This separation maintains both low complexity and high reliability.
4Ease of operation
If the resistance value of externally attached resistor is adjusted to change switching cycle, then the ease of operation is improved, but the device complexity increases due to requiring additional dedicated terminal
Solution Approach 1:
The patent applies multi-functionality by enabling existing terminals (OUT terminal or IS terminal) to serve dual purposes: their original functions plus operation condition setting function. The condition setting circuit utilizes the existing terminal structure to detect resistance values during initialization period, allowing operation mode selection without adding dedicated terminals. This resolves the contradiction by making existing components perform multiple functions.
Data Source
AI summary
To provide a switching power supply device, and an operation condition setting method thereof, wherein it is possible to set an operation condition during an initialization period by adjusting the resistance value of a resistor that grounds an OUT terminal or IS terminal.A switching power supply device includes an oscillator circuit (3) that regulates the switching frequency of a switching element (Q1), a drive circuit (4) that turns (Q1) on and off based on an oscillation signal from the oscillator circuit (3), a condition setting circuit (6), disposed inside a power supply control IC (100) configured to include the oscillator circuit (3) and drive circuit (4), that outputs a condition indicating signal for indicating an operation condition of the switching power supply device, and a control circuit (1) that instructs the condition setting circuit (6) to determine a condition indicating signal within an initialization period immediately after the start of a supply of power to the power supply control IC (100), wherein a first resistor (R1) having an adjusted resistance value is connected to an external terminal of the power supply control IC (100) from which is output a drive signal to (Q1).