Cascode Switching Power Supply Circuit for Heat Loss Reduction
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Solution Overview
Problem
Conventional switching power supply circuits experience heat loss and reliability issues due to the presence of resistors used for feedback control, which complicates heat management and reduces the lifespan of components like electrolytic capacitors.
Innovation Solution
A switching power supply device utilizing a cascode element composed of a normally-on and a normally-off transistor, controlled by a drive signal that changes states based on the midpoint potential between the transistors, reducing the need for resistors and enhancing response speed and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a resistor is used for feedback control in a switching power supply circuit, then the current flowing through the choke coil can be controlled, but heat loss occurs at the resistor which decreases reliability
Solution Approach 1:
The patent removes the resistor from the feedback control path by using the midpoint potential of the cascode element directly for control purposes. The control circuit now samples the midpoint potential between the normally-on and normally-off transistors without requiring a series resistor, thereby extracting the harmful heat-generating component from the system while maintaining current control capability through the cascode element's inherent voltage characteristics.
2Duration of action of stationary object
If a resistor is used for feedback control, then current control is achieved, but heat release design becomes difficult which decreases component lifespan
Solution Approach 1:
The resistor that generated excessive heat and complicated thermal management is completely removed from the circuit. The feedback control now utilizes the midpoint potential of the cascode element directly, eliminating the heat source and simplifying heat release design for stationary components like electrolytic capacitors, thereby extending their operational lifespan.
3Speed
If a conventional switching element is used, then the circuit structure is simple, but the response speed is slow and loss is high
Solution Approach 1:
The patent merges a normally-on type transistor and a normally-off type transistor into a single cascode element where the normally-on transistor provides high-speed response and low loss characteristics, while the normally-off transistor provides controllability. This combination achieves both fast response speed and low loss without significantly increasing overall circuit complexity, as the cascode configuration integrates both functions in a compact structure.
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 configuration reduces power loss, minimizes the size of the converter, and enables quick abnormality detection and protection, improving the overall reliability and efficiency of the switching power supply circuit.
Implementation Method 1
a cascode element including a normally-on type transistor and a normally-off type transistor that are cascode-connected
Data Source
AI summary
A switching power supply circuit includes a pair of input nodes to which an input voltage is applied, a pair of output nodes from which an output voltage is outputted and to which a load is connected, a cascode element and a coil connected between the input node and the output node, and a control circuit outputting a drive signal that controls a conduction state of the cascode element. The control circuit controls the conduction state of the cascode element in response to a potential of a point connecting a normally-on type transistor and a normally-off type transistor that constitute the cascode element.