Functional description

STV9211

12/37

2.8

Cut-off adjustment, Infra-black level (Vib) (3x8 bits)

The Infra-black level (Vib) is the output voltage during the blanking time (BLK). This level is sampled

after each line (sample - and - hold block) during an internal pulse (OCL) which is generated during

the blanking pulse (see

The STV9211 allows to adjust independantly the cut-off levels of the 3 video outputs with a high

resolution. This is done via 3 registers (IBR, IBO and IBL) programming respectively:

q

the range: 1.3 or 1.8V (i.e: 26 or 36V in kit with the STV95xx amplifiers)

q

the offset (to keep the video signal inside thelinear area)

q

the level.

Infra-black range register (IBR: Register 14, bit 0. See I²C table 6)

This register must be selected first, either to 1.3V to get a 26V Cut-off adjustment range with the

STV95xx amplifier or to 1.8V to get a 36V range (see

Infra-black offset register (IBO: Register 14, bit 1, 2 & 3. See I²C table 6)

This register select the Vib offset. It allows to keep the video signal inside the linearity area of

the amplifier.

The value of this register depends on the amplifier high voltage supply (Vdd).

In kit with the STV95xx amplifier family, we recommend the following programming:

Example:

For Vdd=101V +/-5% and Brightness before Drive, IBO must be set to 100.

Infra-black level register (IBL: Register 10, 11, 12. See I²C table 1)

These three 8 bit- registers adjust independantly the infra-black level of the 3 outputs with a high

Table 1: Setting of the infra-black offset register (IBO)

Vdd (±5%)

Case 1:

Brightness before Drive

Case 2:

Brightness after Drive

Binary

Decimal

Binary

Decimal

112 to 115V

001

1

011

3

107 to 111V

010

2

100

4

102 to 106V

011

3

101

5

97 to 101V

100

4

110

6

92 to 96V

101

5

111

7

88 to 91

110

6

111

7

87 and below

111

7

111

7