NTE7134 데이터 시트보기 (PDF) - NTE Electronics

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NTE7134

Integrated Circuit Horizontal and Vertical Deflection Controller for Monitors

NTE Electronics 

Functional Description (Cont’d):

X–Ray Protection

The X–ray protection input XRAY (Pin2) provides a voltage detector with a precise threshold. If the

input voltage at XRAY exceeds this threshold for a certain time, an internal latch switches the IC into

protection mode. In this mode several pins are forced into defined states:

Horizontal output stage (HDRV) is floating

B+ control driver stage (BDRV) is floating

Vertical output stages (VOUT1 and VOUT2) are floating

CLBL provides a continuous blanking signal

The capacitor connected to HPLL2 (Pin31) is discharged

To reset the latch and return to normal operation, VCC has to be temporaily switched off.

Vertical Oscillator and Amplitude Control

This stage is designed for fast stabilization of vertical amplitude after changes in sync frequency con-

ditions. The free–running frequency fosc(V) is determined by the resistor RVREF connected to Pin23

and the capacitor CVCAP connected to Pin24. The value of RVREF is not only optimized for noise and

linearity performance in the whole vertical and EW section, but also influences several internal refer-

ences, Therefore the value of RVREF must not be changed. capacitor CVCAP should be used to select

the free–running frequency of the vertical oscillator in accordance with the following formula:

fosc(V) =

1

10.8 x RVREF x CVCAP

To achieve a stabilized amplitude the free–running frequency fosc(V), without adjustment, should be

at least 10% lower than the minimum trigger frequency. The contributions shown in Table 2 can be

assumed.

Table 2. Calculation of fosc(V) total spreads

Contributing elements:

Minimum frequency offset between fosc(V) ±10%

and lowest trigger frequency

Spread of IC

±3%

Spread of RVREF

Spread of CVCAP

Total

±1%

±5%

19%

Results for 50 to 110Hz application:

fosc(V) =

50Hz

1.19

= 42Hz

Application hint: VAGC (Pin22) has a high input impedance during scan, thus the pin must not be

loaded externally. Otherwise non–linearities in the vertical output currents may occur due to the

changing charge current during scan.

Application hint: The full vertical sync range of 1 : 2.5 can be made usable by incorporating an ad-

justment of the free–running frequency. Also the complete sync range can be shifted to higher fre-

quencies (e.g. 70 to 160Hz) by reducing the value of CVCAP.

Adjustment of Vertical Size, Vertical Shift and S–Correction

VPOS (Pin17) is the input for the DC adjustable vertical picture shift. This pin provides a phase shift

at the sawttoth output VOUT1 and VOUT2 (Pin13 and Pin12) and the EW drive output EWDRV

(Pin11) in such a way that the whole picture moves vertically while maintaining the correct geometry.

The amplitude of the differential output currents at VOUT1 and VOUT2 can be adjusted via input

VAMP (Pin18). This can be a combination of a DC adjustment and a dynamic waveform modulation.

VSCOR (pin19) is used to adjust the amount of vertical S–correction in the output signal.

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