File name OZ960.pdf
Intelligent CCFL Inverter Controller
· · · · · · · · · · · Supports wide-range voltage input applications (8v to 20v) Built-in intelligence to manage ignition and normal operation of CCFLs Reduces the number of components and board size by 30% compared with conventional designs 85% efficiency vs. typical 70% efficiency of conventional designs Zero-voltage-switching full bridge topology Built-in internal open-lamp and over-voltage protections Integrated burst mode control, and wide dimming range (10% to 100%) with integrated burst mode control Supports multiple CCFL lamps Simple and reliable 2-winding transformer design Constant-frequency design eliminates interference with LCDs Low stand-by power quality waveform received, at the CCFL voltage and current. The OZ960 operates at a single, constant frequency in a phase-shift PWM mode. Intelligent open-lamp and over-voltage protections provide design flexibility so various transformer models/manufacturers may be used. The built-in burst mode control provides a wide dimming range and simplifies the application circuit designs. Both operating and burst-mode frequencies are user-programmable parameters. The single stage design results in a low cost, reliable transformer without expensive, less reliable secondary fold-back treatment. The transformer does not require a more expensive center tapped primary. The OZ960 is available in a 20-pin SSOP package. It is specified over the commercial temperature range of 0°C to +70°C, and the industrial temperature range of -40°C to +85°C.
OZ960S - 20-pin plastic SSOP 150mil OZ960IS - 20-pin plastic SSOP 150mil OZ960G - 20-pin plastic SOP 300mil OZ960IG - 20-pin plastic SOP 300mil OZ960D - 20-pin plastic DIP 300mil OZ960ID - 20-pin plastic DIP 300mil
FUNCTIONAL BLOCK DIAGRAM
Refer to the functional block diagram in Figure 2, page 3, and the Pin Description Table on page 4. A precision reference provides a reference voltage for both internal and external uses. An oscillator circuit generates a user-programmable operating frequency with an external capacitor and a timing resistor. In addition, another resistor to program striking frequency is provided. The drive circuit consists of four outputs. These are designed to achieve zero-voltage switching, fullbridge applications. An error amplifier is provided to regulate the CCFL current. The Soft-start circuit offers a gradual increase of the power to the CCFL during the ignition period. The overvoltage protection block offers a regulated striking voltage for CCFLs. The striking time is programmable simply through an external component. The open-lamp protection is integrated in the protection block. This block intelligently differentiates the striking condition and open-lamp condition. ENA circuitry enables the operation of the IC through a TTL signal interface. Wide-dimming control is achieved through the burst-mode control block.
The OZ960 is a unique, high-effic