Trans‐admittance control for eliminating the temperature effect of piezoelectric transformer in the CCFL backlight module

Self Cite

A novel energy-retaining power supply for AC arc welding machines is proposed in this paper. In this kind of power supply, current-steering diodes connected across the output chokes keep the inductor current continuous and retain the energy during the commutation period, hence reducing the commutation time to ensure a better welding performance. In addition, the stored energy can be released in the next energy transfer cycle to raise the conversion efficiency. The circuit operations and design procedures are likewise examined thoroughly. Experimental results on a prototype inverter for driving a 100-A AC arc welding machine are recorded to validate the effectiveness of the presented scheme.

Section: Introductionmentioning

confidence: 99%

A novel energy‐retaining inverter for AC arc welding machines

Jian‐min

Chiu

2012

Self Cite

“…To ignite the lamp, we use a piezoelectric transformer (PT), instead of an electromagnetic type step-up transformer, in a CCFL driving circuit for the advantages of miniature volume, high efficiency, fine insulation, no EMI, etc. [4][5][6][7]. To reduce the number of circuit components, we adopt an integrated circuit (IC) as the controller for the said driving circuits.…”

Section: Introductionmentioning

confidence: 99%

Design and implementation of a digital control IC for driving multiple cold cathode fluorescent lamps

Shin¹,

Yang²

2008

This study designs and develops a digital control integrated circuit (IC) for driving circuits operating multiple cold cathode fluorescent lamps (CCFLs). The control IC adopts an external crystal oscillator for the IC's external frequency to provide the driving circuits a fixed frequency. Inside the IC, two control loops are designed, under synchronized operation frequencies, for a boost regulator and an inverter. The main function of the boost regulator control loop is to supply a steady DC voltage for the inverter. In designing the inverter's control circuit, an adjustable-frequency adjustable-voltage soft-start technique is used to start the lamps. We also use burst mode digital dimming technique to achieve synchronized dimming for the parallel-connected lamp-ignition circuits. The feedback voltage from the CCFLs can determine if any lamp is abnormal via a proposed lamp abnormality detection circuit. To deal with the equivalent-circuit's component parameter differences among various manufacturers' and brands' piezoelectric transformers (PTs), the inverter's operation frequency is designed fine-tunable in this study. Finally, the proposed design concept was implemented with an actual control IC and a driving circuit for CCFLs. The measured data and waveforms from our test circuitry are presented, which verifies the validity of the miniaturized controller proposed in this study.

A high‐input‐voltage backlight module driver for multi‐lamp LCD panels

Pai

et al. 2011

SUMMARYA half-bridge (HB) resonant inverter for driving a backlight module with multiple cold cathode fluorescent lamps (CCFLs) is proposed. Conventionally, a backlight module driving inverter is designed to operate with a low-input DC voltage. Therefore, a buck converter is required to step down the high-output DC voltage of a power factor correction (PFC) pre-regulator. The circuit cost is high and the conversion efficiency is low. In this letter, a high-input-voltage HB resonant inverter with only one transformer is used to drive multiple lamps. Analysis and design considerations are discussed in detail. Simulations and experimental results are close to the theoretical prediction.