OZ964
CONFIDENTIAL
OZ964-DS-1.2
Page 8
6. Open Lamp Protection
If the controller encounters an open lamp,
damaged lamp or lamp removal during normal
operation, the control loop generates a protection
signal and will immediately shutdown the
controller.
OZ964 provides a shutdown delay feature that
keeps the inverter module in normal operation if
the
input
voltage
suddenly
drops
and
subsequently recovers. The shutdown delay time
is user-defined by external resistor RCTIMR (R5)
and external capacitor CCTIMR (C6) connected to
CTIMR (pin 1).
The shutdown delay time is approximated by the
following equation:
CCTIMR[µF] x (3 – (RCTIMR [kΩ] * 0.03))
T[second] =
30
Note: RCTIMR (R5) value equal or greater than
110kΩ will result in zero delay time.
Toggling ENA (pin 3) from High-Low-High resets
the controller.
7. Over-Voltage Protection &
Striking Time
During start-up, once the voltage at the
transformer secondary reaches a programmed
threshold, the control loop takes over and
regulates
the
voltage
at
the
transformer
secondary. SST voltage at pin 4 is held constant
and CTIMR is activated to provide additional time
to ignite an aged CCFL. If no current is sensed
after approximately 1 to 2 seconds, the controller
shuts down. Toggling the ENA pin will reset the
controller.
8. PWM Dimming Control
OZ964 provides a low frequency PWM (LPWM)
dimming function to perform a wide dimming
range of 0% to 100%. The LPWM frequency is
determined by external capacitor C10 connected
to LCT (pin 15). The frequency is approximated
by the following equation.
1496
f LF[Hz] =
CLCT[nF]
The LPWM frequency is user-defined by the
selection of external capacitor C10. An analog
voltage at DIM (pin 14) is compared with the LCT
waveform that yields a LPWM signal to control
the power delivered to the CCFLs. The typical
peak and valley of the LCT waveform is ~2.06V
and ~0.31V respectively.
Chinese ▼
English
Chinese
German
Japanese
Russian
Korean
Spanish
French
Italian
Portuguese
Polish
Vietnamese
Indian
Mexican
British
New Zealand
