NTE7131 View Datasheet(PDF) - NTE Electronics

Part Name

Description

Manufacturer

NTE7131

Integrated Circuit DC–Coupled Vertical Deflection Circuit

NTE Electronics 

Notes:

Note 3. The linearity error is measured without S–correction and based on the same measurement

principle as performed on the screen. The measuring method is as follows:

Divide the output signal I4 – I7 (VRM) into 22 equal parts ranging from 1 to 22 inclusive. Measure

the value of two succeeding parts called one block starting with part 2 and 3 (block 1) and

ending with part 20 and 22 (block 10). Thus part 1 and 22 are unused. The equation for linearity

error for adjacent blocks (LEAB) and not adjacent blocks (NAB) are given below

LEAD =

ak

– a(k + 1)

aavg

; NAB =

amax – amin

aavg

Note 4. Related to VP.

Niote 5. V values within formulae, relate to voltages at or between relative pin numbers, i.e. V7–4/V1–2

= voltage value across pins 7 and 4 divided by voltage value across pins 1 and 2.

Note 6. V9–4 AC short–circuited.

Note 7. Frequency response V7–4/V9–4 is equal to frequency response V7–4/V1–2.

Note 8. At V(ripple) = 500mV eff; measured across RM; fi = 50Hz.

Functional Description:

The vertical driver circuit is a bridge configuration. The deflection coil is connected between the output

amplifiers, which are driven in phase opposition. An external resistor (RM) connected in series with

the deflection coil provides internal feedback information. The differential input circuit is voltage driv-

en. The input circuit has been adapted to enable it to be used with devices that deliver symmetrical

current signals. An external reisitor (RCON) connected between the differential input determines the

output current through the deflection coil. The relationship between the differential input current and

the output current is defined by: Idiff x RCON = Icoil x RM. The output current is adjustable from 0.5A(p–p)

to 2A(p–p) by varying RM. The maximum input differential voltage is 1.8V. In the application it is recom-

mended that Vdiff = 1.5V (Typ). This is recommended because of the spread of input current and the

spread in the value of RCON.

The flyback voltage is determined by an additional supply voltage VFB. The principle of operating with

two supply voltages (class G) makes it possible to fix the supply voltage VP optimum for the scan volt-

age and the second supply voltage VFB optimum for the flyback voltage. Using this method, very high

efficiency is achieved.

The supply voltage VFB is almost totally available as flyback voltage across the coil, this being pos-

sible due to the absence of a decoupling capacitor (not necessary, due to the bridge configuration).

The output circuit is fully protected against the following:

D Thermal Protection

D Short–Circuit Protection of the Output Pins (Pin4 and Pin7)

D Short–Circuit of the Output pins to VP.

A guard circuit VO(guard) is provided. The guard circuit is activated at tghe following conditions:

D During Flyback

D During Short–Circuit of the Coil and During Short–Circuit of the Output Pins (Pin4 and Pin7) to

VP or GND

D During Open Loop

D When the Thermal Protection is Activated

This signal can be used for blanking the picture tube screen.

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