Switching Power Supply Control Circuit with Current Selection
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Solution Overview
Problem
Switching power supplies often require multiple output current values, but existing technologies lack a simple and cost-effective method to adjust and switch between these current values efficiently.
Innovation Solution
A control circuit with a central control circuit and a current selection circuit that switches between disconnection, shorting, and connection with a resistor to adjust the output current value, using multiple selection terminals and switching elements with different trigger voltages to control the connection states.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple resistors are used to control different output current values, then the output current adjustment capability is improved, but the device complexity and cost increase
Solution Approach 1:
The switching element serves multiple functions: it acts as a switch to select different resistors, and simultaneously its on/off state directly determines which resistance value is connected to the control port. This multi-functionality reduces the need for separate control circuits for each current value, thereby simplifying the overall circuit while maintaining multiple output current adjustment capabilities
Solution Approach 2:
Multiple resistors with different resistance values are pre-configured in the circuit before operation. The switching element can instantly connect any of these pre-configured resistors to the control port, enabling rapid switching between different output current values without requiring complex real-time calculation or adjustment mechanisms
2Adaptability or versatility
If multiple resistors are used to control different output current values, then the output current adjustment capability is improved, but the manufacturing cost increases
Solution Approach 1:
The current adjustment function is segmented into discrete resistance values, each provided by a separate resistor. This segmentation allows for modular design where each resistor can be independently selected and replaced, simplifying the manufacturing process and reducing overall cost compared to using a single complex adjustable resistor or digital-to-analog converter circuit
Solution Approach 2:
The patent uses simple, inexpensive resistors and a basic switching element instead of expensive precision adjustable components. The resistors are standard values that can be easily sourced, and the switching element is a simple semiconductor device, making the overall circuit cost-effective and easy to manufacture in volume
3Productivity
If a complex switching mechanism is used to change resistance values, then the output current switching capability is improved, but the device complexity increases
Solution Approach 1:
The patent replaces mechanical switching mechanisms (such as rotary switches or slide switches) with an electronic switching element. This electronic switch can change states instantaneously without mechanical wear or contact bounce, achieving fast current switching capability while reducing mechanical complexity and improving reliability
Solution Approach 2:
The switching element provides dynamic control of the circuit configuration. By changing the switching element's state, the circuit dynamically reconfigures to connect different resistors, enabling rapid adaptation to different output current requirements without physical reconfiguration or complex mechanical movements
Data Source
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AI summary
The present application provides a control circuit of a switching power supply, the control circuit comprising: a central control circuit which has a first control port, a second control port, and a third control port; and a current selection circuit which is disposed between the third control port and a ground and has two or more selection terminals, a connection state between the selection terminals being switched between different connection states to adjust the output current value of the switching power supply, wherein the different connection states include disconnection, shorting, and connection with a resistor having a predetermined resistance value. According to the present application, the output current value of the switching power supply is adjusted by switching the connection state between the selection terminals between the states of disconnection, shorting, and connection with a resistor having a predetermined resistance value.