tza1032 NXP Semiconductors, tza1032 Datasheet - Page 14

• Manufacturer Part Number: tza1032
• Description: Laser Driver And Controller Circuit
• Manufacturer: NXP Semiconductors

Philips Semiconductors
7.7
The write strategy generator makes use of pointer memory
mapping to allow compact write strategy coding. Only
1600 bytes have to be transferred to TZA1032 to load the
most complex write strategy including write
pre-compensation. Due to the pointer memory structure
common strategies can be loaded in an even more
compact manner (e.g. CD strategies). Loading can be
done efficiently via I
The write strategy code includes:
The modulation information enables the user to switch on
modulation in pre-selected parts of the write strategy on
a real time basis. The modulation amplitude can be
programmed asynchronously via I
7.8
The Forward Sense Diode (FSD) is a reversed biased
diode that receives a small percentage of the laser output
light and converts it into a current. The FSD can be
connected directly to the TZA1032 without additional
components. The TZA1032 features a current input with
programmable gain (6-bit resolution). Furthermore a 12-bit
ADC is used.
2002 May 06
Data for selection of output power levels from 4
threshold and 8 delta values (these 8-bit values can be
programmed asynchronously via I
Pulse timing information
Modulation information.
Laser driver and controller circuit
Write strategy generator
Laser Power Control
2
C-bus block transfer mode.
2
C-bus.
2
C-bus)
14
Internal set point generation is present to allow read-write
switching without any transient effects. A digital loop filter
with programmable loop gain is used. This allows tailoring
of loop bandwidth according to the requirements of the
application. A unique laser power control algorithm is
used. This algorithm ensures not only average power
control but it really makes the laser virtual temperature and
aging independent for any possible write strategy. This
loop operates with or without the alpha (running OPC)
loop.
The TZA1032 supports a full running optimum power
control loop when required by the user. The loop is also
referred to as the alpha loop. The input signal is based on
disc Absorption MEASurements (AMEAS). This signal is
processed in a similar way as the FS input current.
A current input is provided with programmable gain (4-bit)
and an 8-bit ADC is used.
Again a digital loop filter with programmable loop gain is
used. This allows tailoring of loop bandwidth according to
the requirements of the application. The alpha loop does
not interfere with the FS laser power control loop.
Therefore, both control loops can be used simultaneously.
The set point is programmable via I
control of a programmable OPC stepper.
Preliminary specification
2
C-bus or is under
TZA1032