Color TV Signal Encoder

Transcription

1 Color TV Signal Encoder The converts analog RGB signals into color TV signals in the NTSC and PAL formats. From inputs of analog RGB signals, a composite synch signal, burst pulses and a color carrier, this IC generates a color TV signal, and can be adapted for either NTSC or PAL standards, which are selected externally. When set to PAL, the changes chroma phase according to the burst flag pulses. The chroma signals and luminosity signals can be combined into a color TV signal or output separately, making this IC suitable for S pins. Also, this IC comes with an output pin for the analog RGB signal. Each output has a built-in driver. Applications TV peripherals Features ) Can be adapted for NTSC and PAL formats. ) Internal flip-flop for PAL phase switching. ) Separate Y / C output pins. ) Analog RGB signal output pins. Block diagram ) Internal driver. (outputs color TV signals, luminosity signals, chroma signals and analog RGB signals) ) Adaptable for color subcarrier pulse input. BIN 0 BOUT GIN 9 GOUT RIN 8 ROUT BURST MATRIX 7 IN OUT IN PHASE B - Y MOD. R - Y MOD. YOUT NT / PAL 7 F F N.C. SCIN 8 FILTER Y / C VOUT 9 N.C. COUT 0

2 Pin descriptions Pin No. Pin name Function BIN Analog B signal input GIN Analog G signal input RIN Analog R signal input IN Power supply pin for all drivers other than the driver Composite synchronization signal input (negative logic) IN Burst flag pulse input (negative logic) 7 NT / PAL Selecting the type of color TV signal output (high = NTSC, low = PAL) 8 SCIN Color subcarrier input 9 Ground for all drivers other than the driver 0 COUT Chroma signal output. Internal driver. Ground for the driver N.C. This pin is not connected inside the IC. VOUT Color TV signal output. Internal driver. N.C. This pin is not connected inside the IC. YOUT Luminance signal output. Internal driver. OUT Composite synchronization signal output 7 Power supply pin for all drivers other than the driver 8 ROUT Analog R signal output. Internal driver 9 GOUT Analog G signal output. Internal driver. 0 BOUT Analog B signal output. Internal driver. Absolute maximum ratings (Ta = C) Parameter Symbol Limits Unit Power supply voltage 7 V Power dissipation Pd 0 mw Operating temperature Topr 0 ~ 70 C Storage temperature Tstg ~ C Reduced by 7.mW for each increase in Ta of C over C. When mounted on a mm glass epoxy board. Recommended operating conditions (Ta = C) Parameter Symbol Limits Unit Power supply voltage. ~. V RIN input level υri 0 ~ 0.7 VP-P GIN input level υgi 0 ~ 0.7 VP-P BIN input level υbi 0 ~ 0.7 VP-P SCIN input level υsc 0. ~ 0. VP-P

3 Electrical characteristics (unless otherwise noted, Ta = C, = V, XTAL =.8MHz) Parameter Symbol Min. Typ. Max. Unit Conditions Current dissipation ICC ma Luminance level υl VP-P υri = υgi = υbi = 0.7VP-P Luminance level R υl(r) VP-P υri = 0.7VP-P YOUT VOUT Luminance level G υl(g) VP-P Luminance level B υl(b) VP-P Synchronization level υs VP-P Synchronization / luminance level ratio YOUT DC voltage COUT DC voltage VOUT DC voltage ROUT DC voltage GOUT DC voltage BOUT DC voltage R S/L RYO = υs / υl R / burst level ratio RR/BU.8..8 υri = 0.7VP-P G / burst level ratio RG/BU..9. υgi = 0.7VP-P B / burst level ratio RB/BU.0..7 υbi = 0.7VP-P R phase θr 9 0 deg G phase θg deg COUT VOUT B phase θb deg Burst level υbu VP-P Carrier leak υcl mvp-p PAL burst phase θbu deg SW = θbu deg SW = PAL burst level ratio RBU SW = OUT Output level (HIGH) V Output level (LOW) V ROUT output level υro VP-P υri = 0.7VP-P GOUT output level υgo VP-P υgi = 0.7VP-P BOUT output level υbo VP-P υbi = 0.7VP-P VYO V VCO V VVO... V VRO...0 V VGO...0 V VBO...0 V υgi = 0.7VP-P υbi = 0.7VP-P Input voltage "L" level,, NT / PAL Input voltage "H" level,, NT / PAL Input impedance,, NT / PAL VIL 0.8 V VIH. V ZI 8. kω Guaranteed performance. Measured. µs after burst with a.8 MHz BPF. Measured with a.8 MHz BPF. Not designed for radiation resistance.

4 Measurement circuit BIN input GIN input RIN input BURST MATRIX BOUT GOUT ROUT OUT Composite synch Burst flag pulse () SW 7 F F PHASE B - Y MOD. R - Y MOD. K YOUT Color subcarrier.7k 0 8 FILTER Y / C VOUT 9 COUT 0.7µ 0

5 Circuit operation () IN is for composite synch input. During low input, the synchronization signal is output to YOUT, VOUT and OUT. () is for burst flag pulse input. During low input, the burst signal is output to pins CO and VO. When the IC is set to PAL, it is this signal that directs the phase inversion of the chroma signals. This signal also controls the timing of the pedestal clamps of RIN, GIN and BIN. During low input, the pedestal levels of RIN, GIN and BIN are kept constant by charging an attached capacitor. () NT / PAL is the NTSC / PAL selector pin, and connects to when set to NTSC and to when set to PAL. () SCIN is for color subcarrier input. Set input to a pulse wave or sine wave (.79MHz for NTSC and.9mhz for PAL). () COUT and YOUT are for output of chroma signals and luminosity signals, respectively. Because the chroma signal and luminosity signals can be output separately, the IC can be adapted for S pins. Each has a driver. () VOUT is for color TV signal output, and has an internal driver. (7) ROUT, GOUT and BOUT are for analog RGB signal output, and have an internal driver. The relationship between chroma phase and burst phase during PAL processing is as follows. NT / PAL Chroma phases burst R - Y B - Y B - Y B - Y burst R - Y burst R - Y

6 Application example (NTSC color TV signals) Analog B signal 0 Analog G signal 9 Analog R signal 8 7 PHASE BURST MATRIX Composite synch Composite synch output Burst flag pulse () B - Y MOD. R - Y MOD. 7 F F Color subcarrier.7k 0 8 FILTER Y / C Color TV signal output 9 0 Operation notes () Input impedance at the input terminals should be as low as possible as the analog RGB signal is clamped there. () The color subcarrier should have a duty of 0%. Duty fluctuation will affect chroma phase. Resistancesplitting input is used in the "Application example" to accommodate VP-P CMOS input. For other types of input, adjust to 0.VP-P at SCIN. () Composite synch and burst flag pulse inputs should conform to their respective standards, as improper timing between them can prevent the TV from displaying color images. For input, use the TTL level and an impedance of 8kΩ. External dimensions (Units: mm) 7.8 ± 0.. ± 0..8 ± ± ± 0. 0.Min. SSOP - A0 0. ± 0. 0.