Power Converter Control Circuit Using Segmented Ground References
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Solution Overview
Problem
Conventional power converters for high-power LED lighting, such as charge-pump half-bridge resonant power converters, incur high costs due to the complexity of isolating drive signals for transistors using drive transformers.
Innovation Solution
A control circuit for a power converter with a bridge arm comprising two transistors, where the first controller generates control signals based on feedback signals, and the second controller isolates drive signals by using different ground references, simplifying the circuit structure and reducing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If drive transformers are used to isolate drive signals of transistors, then signal isolation is achieved, but circuit cost and complexity increase greatly
Solution Approach 1:
The patent divides the control system into two independent controllers: a first controller with ground reference at the intermediate node that generates control signals for the first transistor, and a second controller with ground reference at the input end that generates control signals for the second transistor. This segmentation eliminates the need for drive transformers while maintaining signal isolation through independent ground references.
Solution Approach 2:
The patent introduces an intermediate node in the bridge arm as a mediator that serves as the ground reference for the first controller. This intermediate node acts as a reference potential that enables independent control of the first transistor without requiring galvanic isolation through transformers, thereby simplifying the circuit while maintaining proper signal isolation.
2Reliability
If drive transformers are used to isolate drive signals, then transistor control isolation is achieved, but manufacturing cost increases
Solution Approach 1:
The control system is segmented into two independent controllers with different ground references. The first controller uses the intermediate node as ground reference while the second controller uses the input end as ground reference, eliminating the need for expensive drive transformers and reducing manufacturing cost.
Solution Approach 2:
The patent extracts the drive transformer component from the circuit by implementing control isolation through independent ground references in the controllers. This removal of the transformer while maintaining isolation functionality significantly reduces component cost and simplifies manufacturing.
3Device complexity
If a single ground reference is used for both controllers, then circuit simplification is achieved, but drive signal isolation is lost
Solution Approach 1:
The patent segments the ground reference system into two independent references: one at the intermediate node for the first controller and another at the input end for the second controller. This segmentation maintains circuit simplicity by avoiding transformers while preserving signal isolation through the independent ground references.
Data Source
AI summary
A power converter, a control circuit and a control method for the same. Ground references of a first controller and a second controller are different to isolate drive signals of a first transistor and a second transistor. Thus the first transistor and the second transistor are controlled to be switched between on and off alternatively to achieve power conversion. The circuit is simple in structure and easy to implement with a low cost. The ground reference of the first controller is an intermediate node of a bridge arm of the power converter, so as to facilitate sampling and acquiring a feedback signal, thereby achieving closed-loop control of the power converter.