Converter Circuit Current Sensing with Single Switch Control
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Solution Overview
Problem
Existing converter circuits for lighting systems face challenges in achieving high power factor and low total harmonic distortion while reducing costs and complexity, and efficiently sensing current without complex external circuitry.
Innovation Solution
A converter circuit comprising an actively switched boost converter stage and a DC-to-DC converter stage, controlled by a single switch, with current sensing elements configured to sense currents relative to ground potential, simplifying the control and reducing the number of electronic components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple switches are used to control each converter stage separately, then each stage can be independently optimized, but the device complexity and cost increase
Solution Approach 1:
The patent combines the control of the boost converter stage and DC-to-DC converter stage into a single integrated switch. This single switch performs the switching function for both converter stages simultaneously, reducing the total number of switches from two to one while maintaining the ability to control both stages effectively
Solution Approach 2:
The single switch is designed to serve multiple functions: it controls the boost converter stage during the first time period and controls the DC-to-DC converter stage during the second time period. This multi-functional design allows one component to replace what would traditionally require two separate components
2Difficulty of detecting and measuring
If current is sensed with respect to a variable potential, then the sensing can be done within the converter circuit, but the external circuitry for evaluation becomes complex
Solution Approach 1:
The patent senses the current of the first electrical energy storage element with respect to a fixed low potential (ground) rather than a variable potential. This creates an equipotential reference point that simplifies the evaluation circuitry, as the voltage measurement is always referenced to a stable ground potential regardless of the switching state
3Device complexity
If a single switch controls both converter stages, then cost and complexity are reduced, but the control strategy becomes more challenging
Solution Approach 1:
The control strategy uses periodic action by dividing the switching cycle into two distinct time periods. During the first time period, the single switch controls the boost converter stage; during the second time period, the same switch controls the DC-to-DC converter stage. This time-division multiplexing approach makes the control of a single switch equivalent to controlling two separate switches
Data Source
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AI summary
The present invention discloses a converter circuit for converting an input voltage into an output voltage, wherein the converter circuit comprises an actively switched boost converter stage with a first electrical energy storage element, an actively switched DC-to-DC converter stage with a second electrical energy storage element, a switch controllable by a controller for operating both the actively switched boost converter stage and the actively switched DC-to-DC converter stage, a first current sensing element, and a second current sensing element; wherein the first current sensing element and the second current sensing element are configured to sense the current of the first electrical energy storage element and the current of the second electrical energy storage element with respect to the low potential of the converter circuit, preferably with respect to ground potential, when the switch is in the conducting state. The present invention further discloses an operating device for lighting means with such a converter circuit as well as a lighting device with such an operating device and lighting means.