| Secciones |
|---|
|
|
| Foros Electrónica |
| Alguien dijo ... |
| Ciencia es creer en la ignorancia de los científicos, Richard Phillips Feynman(1918-1988). Físico estadounidense. Premio Nobel de Física 1965. |
| Contacto |
| Fixed-Frequency CCFL Controller with Synchronization and Phase-Shift Features for Multilamp Applications | ||||||||
SUNNYVALE, CA -Maxim Integrated Products (NASDAQ: MXIM) introduces the MAX8729, a fully integrated controller optimized to drive multiple cold-cathode fluorescent lamps (CCFL) used in LCD monitor and TV applications. The MAX8729 drives multiple lamps by using a half-bridge inverter consisting of two external n-channel power MOSFETs. Its half-bridge topology minimizes the component count, while providing near sinusoidal drive waveforms over the entire input range. The MAX8729 operates in resonant mode during striking, and switches over to fixed-frequency operation after the lamps are lit. This unique feature ensures reliable striking under all conditions and reduces transformer stress. The MAX8729 achieves a 10:1 dimming range by turning the CCFL on and off using a digitally adjusted PWM (DPWM) method. CCFL brightness can be set with an analog voltage on the CNTL pin. Synchronization and phase-shift features for both the switching and DPWM frequencies permit daisy-chaining multiple MAX8729s. The switching and DPWM frequencies can be easily adjusted with external resistors. Phase-shift select pins, PS1 and PS2, can be used to program up to four different phase shifts, allowing up to six MAX8759s to be used together. The gate drivers of the MAX8729 drive large power MOSFETs typically used in applications where one transformer powers four CCFLs in parallel. An internal 5.3V linear regulator powers the MOSFET drivers and most of the internal circuitry. The MAX8729 is available in a low-cost, 24-pin QSOP, and operates over -40 degrees Celsius to +85 degrees Celsius temperature range. Prices start at $4.53 (1000-up, FOB USA). A preassembled MAX8729 evaluation kit with recommended external components is available to reduce design time.
| ||||||||
Martes, 30 Agosto, 2005 - 12:50 | ||||||||
 | ||||||||
