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CXA1372BQ/BS

Commands

The input data to operate this IC is configured as 8-bit data; however, below, this input data is represented by

2-digit hexadecimal numerals in the form $XX, where X is a hexadecimal numeral between 0 and F.

Commands for the CXA1372 can be broadly divided into four groups ranging in value from $0X to $3X.

1. $0X (“FZC” at SENS (Pin 27))

These commands are related to focus servo control.

The bit configuration is as shown below.

D7

D6

D5

D4

D3

D2

D1

D0

0

0

0

0

FS4

FS3

FS2

FS1

Four focus-servo related switches exist: FS1 to FS4 corresponding to D0 to D3, respectively.

$00

When FS1 = 0, Pin 7 is charged to (22µA – 11µA)

× 50kΩ = 0.55V.

If FS2 = 0, this voltage is no longer transferred, and the output at Pin 5 becomes 0V.

$02

From the state described above, the only FS2 becomes 1. When this occurs, a negative signal is output

to Pin 5. This voltage level is obtained by equation 1 below.

(22µA – 11µA)

× 50kΩ ×

....

Equation 1

$03

From the state described above, FS1 becomes 1, and a current source of +22µA is split off.

Then, a CR charge/discharge circuit is formed, and the voltage at Pin 7 decreases with the time as

shown in Fig. 1 below.

This time constant is obtained with the 50k

Ω resistance and an external capacitor.

By alternating the commands between $02 and $03, the focus search voltage can be constructed. (Fig. 2)

0V

0V

$

00 02

030203

02

00

Fig. 1. Voltage at Pin 7 when FS1 gose from 0

→ 1

Fig. 2. Constructing the search voltage by alternating between $02 and $03 (Voltage at Pin 5)

resistance between Pins 5 and 6

50k

Ω