Current Converter Primary Winding Delay Compensation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing power supplies for solid-state lighting (SSL) applications face challenges in maintaining high power factor and accurate regulation of d.c. output current due to propagation delays and variations in power transistors, which affect the precision of d.c. output current, especially when the total propagation delay is not constant.
Innovation Solution
A control circuit that supplies a feed-forward current proportional to both the input voltage and the total propagation delay, using a feed-forward resistor with a resistance calculated to compensate for the propagation delay, ensuring accurate switching and maintaining high power factor without requiring complex adjustments for different power transistors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a feed-forward current proportional to input voltage is used for control, then high power factor is achieved, but propagation delay causes inaccuracies in d.c. output current regulation
Solution Approach 1:
The patent applies preliminary action by calculating and compensating for the propagation delay in advance. The control circuit determines the delay value and uses it to adjust the feed-forward current before the switching action occurs, thereby eliminating the accuracy error caused by propagation delay while maintaining high power factor operation.
Solution Approach 2:
The patent changes the parameter of feed-forward current by making it proportional to both the input voltage and the calculated propagation delay. This parameter modification allows the control circuit to account for delay effects dynamically, improving current regulation accuracy without sacrificing power factor performance.
2Adaptability or versatility
If different power transistors are used, then design flexibility is improved, but propagation delay variations affect d.c. output current accuracy
Solution Approach 1:
The patent implements feedback by measuring or calculating the actual propagation delay for each power transistor and using this information to adjust the feed-forward current accordingly. This closed-loop approach maintains accurate d.c. output current regulation regardless of which power transistor is used, thereby supporting design flexibility while preserving precision.
Solution Approach 2:
The patent dynamically adjusts the feed-forward current parameter based on the specific propagation delay characteristics of the power transistor being used. This parameter adaptation enables the system to accommodate different transistor variants while maintaining consistent output current accuracy.
3Device complexity
If propagation delay is not compensated, then device complexity is reduced, but d.c. output current accuracy deteriorates
Solution Approach 1:
The patent introduces an intermediary calculation step that determines the propagation delay and uses it as a compensation factor in the feed-forward current. This intermediary element bridges the gap between the simple feed-forward structure and the need for high accuracy, adding minimal complexity while significantly improving current regulation.
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 enables precise regulation of d.c. output current, independent of supply voltage variations and propagation delay changes, ensuring high accuracy and adaptability across different power transistors, thus meeting stringent accuracy requirements in SSL applications.
Implementation Method 1
a transformer 4 including a primary winding Lp, a secondary winding Ls, and an auxiliary winding Laux
Implementation Method 2
a power switch M, formed by a power transistor, for example a MOSFET
Implementation Method 3
The bridge rectifier 2 has two input terminals 10a, 10b, designed to receive an a.c. supply voltage Vac
Data Source
AI summary
A control circuit controls a switch of a switching current converter receiving an input quantity, with a transformer having a primary winding and a sensor element generating a sensing signal correlated to a current in the primary winding. The control circuit has a comparator stage configured to compare a reference signal with a comparison signal correlated to the sensing signal and generate an opening signal for the switch. The comparator stage has a comparator element and a delay-compensation circuit. The delay-compensation circuit is configured to generate a compensation signal correlated to the input quantity and to a propagation delay with respect to the opening signal. The comparator element generates the opening signal with an advanced timing correlated to the input quantity and to the propagation delay.