LED Backlight Driver Using Isolated Converter for Bus Voltage
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Solution Overview
Problem
Conventional LED backlight driver systems are complex, inefficient, and costly due to their multi-stage structures involving multiple converters, which complicates the regulation of LED current and bus voltage.
Innovation Solution
A simplified LED driver system comprising an isolated converter and DC/DC converters that regulate LED current and bus voltage separately using a dimming signal, with the isolated converter receiving an input signal and providing power for the LED string and DC/DC converters, and the DC/DC converters converting the bus voltage to output voltages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a multi-stage driver system with multiple converters is used, then the LED backlight driver system can provide multiple voltage outputs, but the system complexity increases
Solution Approach 1:
The isolated converter is designed to perform multiple functions: it provides both the LED drive current through its secondary winding and generates the bus voltage for DC/DC converters. This multi-functional design eliminates the need for separate power supplies, reducing system complexity while maintaining the capability to provide multiple voltage outputs
2Adaptability or versatility
If a multi-stage driver system with multiple converters is used, then the LED backlight driver system can provide multiple voltage outputs, but the manufacturing cost increases
Solution Approach 1:
The patent merges the functions of multiple power supplies into a single isolated converter. The isolated converter's secondary winding directly provides LED drive current, while its output also generates the bus voltage for DC/DC converters that produce additional voltage outputs. This consolidation reduces component count and manufacturing cost
3Adaptability or versatility
If a multi-stage driver system with multiple converters is used, then the LED backlight driver system can provide multiple voltage outputs, but the efficiency decreases
Solution Approach 1:
The isolated converter operates continuously to provide both LED drive current and bus voltage generation. By maintaining continuous operation of a single primary power conversion stage rather than multiple independent converters, the system reduces energy losses associated with multiple conversion stages and improves overall efficiency
4Measurement precision
If the isolated converter regulates LED current and bus voltage separately, then the regulation precision improves, but the control complexity increases
Solution Approach 1:
The control of LED current and bus voltage is segmented into separate regulation loops within the isolated converter. The secondary winding provides dedicated LED drive current regulation, while the output stage independently regulates bus voltage for DC/DC converters. This segmentation allows precise regulation of each parameter without requiring complex integrated control
Data Source
AI summary
The embodiments of the present circuit and method disclose a light-emitting diode (LED) driver system. The LED driver system may comprise an isolated converter and a DC/DC converter. The isolated converter may be coupled to a first input signal, and may provide a LED current and a bus voltage. The isolated converter may be configured to regulate the LED current and the bus voltage separately in accordance with a dimming signal. The DC/DC converter may comprise an input coupled to the bus voltage.