In accordance with the present invention, the current through CCFL is controlled by a combination of the duty cycle of the driving waveform i. Circuitry within the reference block is used to determine if the reference is close to regulation. The current flowing through resistors and can be sensed at node and then converted from AC to DC using a rectifier e. This frequency should vary inversely with the value of capacitor Because CCFL tubes and are in series their current should be substantially the same. A CCFL circuit comprising:
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Because the oscillator frequency can be adjusted upwards as the battery voltage increases, harmonic distortion of the output waveform can be advantageously minimized. During standard operation, CCFL tubes typically require a sine wave of V and run at a current of several milliamps.
US6940233B2 – Method and system of driving a CCFL – Google Patents
Additional components can be included in system as shown in FIG. As described above, the current through CCFL can be cctl on a linewhich is coupled to node N 3.
In one embodiment, the low voltage is 1. NMOS transistor has its source coupled to VSS and its drain coupled to the positive input terminal of error amplifier as well as to line In one embodiment, the voltage at FCOMP is not allowed to charge or discharge, which keeps the switching frequency constant.
The AC voltage of the midpoint is naturally low compared with the AC voltage at the ends of the transformer.
Protecting a cold cathode fluorescent lamp from a large transient current when voltage supply ccdl from a low to a high voltage. In this embodiment, a user-supplied voltage can set the brightness of the CCFL by determining the duty cycle of the dimming period. For example, dcfl CCFL that is old or cold can take longer to strike.
In this embodiment, one control IC is used to drive ccfll transformers andwherein transformer drives CCFL tubes and and transformer drives CCFL tubes and In methoda timer is started in step VO1 General Description The TS is a low power audio amplifier, it integrated circuit intended primarily for telephone More information.
The detection circuit can include a PCB trace formed within 7 to 15 mils thousandths of an inch of a high voltage connector of the CCFL circuit. A method of physically implementing a transformer, the transformer having a core segment with a middle area, a first end area, and a second end area, the method comprising: An inverter, a backlight assembly and a display device having the same having the same.
US USB2 en At the beginning of every dimming cycle, SSC starts at 0V and ramps linearly up to the Pmoss supply, however the first of these ramps after power up is pmoe slower than subsequent ramps. Therefore, the scope of the present invention is only limited by the appended claims. MP59 1A, 1V, 1.
CNA – Method and system for driving CCFL – Google Patents
The first primary winding is tightly coupled to the second primary winding. PCB track, which is formed in mils thousandths of ccfo inch high voltage circuit connector CCFL within the PCB traces the arc path providing an alternative, it can produce a voltage detection signal representing whether the condition exists. It drives a half bridge topology.
This logic one signal forces the Qbar output terminal to a logic one and the output of inverter to a logic zero. When the voltage at one secondary output is high e. The PCB trace provides a detect signal that indicates whether the over-voltage condition exists. However, the losses associated with transformer can cfl significantly more than the I-squared and switching losses.
DC-AC Converter, Cold Cathode Fluorescent Lighting (CCFL) Power Supply – YouSpice
The overvoltage protection block offers a regulated striking voltage for CCFLs. Note that because standard dimming cycles are on the order of 6 mS, it is probable that 12 mS of maximum brightness as the CCFL turns on will be acceptable.
In this case, resistor can advantageously sense the current in the left tube in the same way resistor senses the current in CCFL RailClamp Description RailClamps are surge rated diode arrays designed to protect high speed data interfaces. The CCFL system of claim 10wherein if a fault occurs, then the second center tap provides a voltage substantially different from voltage source VSS.
The frequency is calculated as: In one embodiment, conditions similar to those in the start up operation can be monitored.