NTE7132 查看數據表（PDF） - NTE Electronics

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NTE7132

Integrated Circuit Horizontal and Vertical Deflection Controller for VGA/XGA and Multi–Frequency Monitors

NTE Electronics 

Functional Description (Cont’d):

PLL2 Phase Detector

This phase detector is similar to the PLL1 phase detector. Line flyback signals (Pin2) are compared

with a fixed point of the oscillator sawtooth voltage. Delays in the horizontal deflection circuit are com-

pensated by adjusting the phase relationship between horizontal sync and horizontal output pulses.

A certain amount of phase adjustment is possible by injecting a DC current froma an external source

into the PLL2 filter capacitor on Pin20.

Horizontal Driver

This open–collector output stage (Pin3) can directly drive an external driver transistor. The saturation

voltage is 300mV at 20mA. To protect the line deflection transistor, the horizontal output stage does

not conduct at VP < 6.4V (Pin1).

Vertical Oscillator and Amplitude Control

This stage is designed for fast stabilization of the vertical amplitude after changes in sync conditions.

The free–running frequency fo is determined by the values of RVOS and CVOS. The recommended

values should be altered marginally only to preserve the excellent linearity and noise performance.

The vertical drive currents I5 and I6 are in relation to the value of RVOS. Therefore, the oscillator fre-

quency must be determined only by CVOS on Pin16.

fo =

1

10.8 x RVOS x CVOS

To acheive a stabilized amplitude the free–running frequency fo (without adjustment) must be lower

than the lowest occurring sync frequency. The contributions shown in Table 1 can be assumed.

Table 1. Calculation of fo Total Spread

Contributing Elements

%

Minimum Frequency Offset Between fo and the Lowest Trigger Frequency

10

Spread of IC

±3

Spread of R (22kΩ)

±1

Spread of C (0.1µF)

±5

Total

19

Results for 50 to 110Hz application: fo =

50Hz

1.19

= 42Hz

Table 2. VGA Modes

Mode Horizontal/Vertical

Sync Polarity

Horizontal

Frequency

(kHz)

Vertical Number of Output

Frequency Active Lines Mode Pin7

(Hz)

1

+/–

31.45

70

350

LOW

2

–/+

31.45

70

400

LOW

3

–/–

31.45

60

480

LOW

4

+/+

Fixed by External Circuitry

–

–

HIGH

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