Two-Channel Interleaved Buck LED Driver Using Current-Balancing Capacitor

This paper introduces an automatic current-balancing multichannel light-emitting diode (LED) driver. The proposed topology is simple in structure, low cost, and can achieve automatic current balancing for multistring LED applications. Owing to the charge-balancing condition of the capacitor, the LED channel currents are automatically equalized without requiring any dedicated control or extra circuitry. Thus, there is only one current-controlled circuit necessary to adjust all LED channel currents. The operating principle and phase-shifted pulsewidth modulation control of the proposed two-channel LED driver are analyzed in detail. The extension to multichannel applications is also discussed. A 25-W hardware prototype was built and tested; the experimental results are provided for validation.