CA3224E

The CA3224E is an automatic picture tube bias control circuit used in color TV receiver CRT drive circuits. It is used to provide dynamic bias control of the grey scale both initially and over the CRT operating life, compensating for CRT cutoff changes.

The CA3224E provides automatic continuous control of the cutoff current in each gun of a three-gun color CRT. From an input pulse amplitude proportional to the difference between the desired and the actual CRT cutoff, a gated sample/hold circuit generates a DC correction voltage which correctly biases the CRT driver circuit. The sample/hold bias correction takes place each frame following the vertical blanking. Figure 1 shows a block diagram of the CA3224E. The functions include three identical servo loop transconductance amplifiers with a sample/hold switch and buffer amplifier plus control logic, internal bias and a mode switch.

The CA3224E is designed as one kind of automatic picture tube bias control circuit which can be used in provide dynamic bias control of the grey scale both initially and over the CRT operating life, compensating for CRT cutoff changes.It also provides automatic continuous control of the cutoff current in each gun of a three-gun color CRT.And the functions of it include three identical servo loop transconductance amplifiers with a sample/hold switch and buffer amplifier plus control logic, internal bias and a mode switch.

Features of the CA3224E are:(1)automatic background color balance;(2)automatic picture tube bias cutoff control;(3)eliminates grey scale adjustments;(4)compensates for cathode-to-heater leakage;(5)electrostatic protection on all pins;(6)servo loop design;(7)wide dynamic range;(8)three-gun control;(9)minimal external components.

The absolute maximum ratings of the CA3224E can be summarized as:(1)supply voltage:11 V;(2)DC input voltage:-1 to Vcc;(3)output current:short circuit protected;(4)temperature range:-40 to 85;(5)supply voltage range (typical):10V±10%;(6)thermal resistance:JA (/W);(7)maximum junction temper-ature (plastic package):150;(8)maximum storage temperature range:-65 to 150;(9)maximum lead temperature (soldering 10s):300.If you want to know more information such as the electrical characteristics about it,please download the datasheet in www.seekic.com or www.chinaicmart.com .