AK2571 Datasheet, PDF (24/52 Pages) Asahi Kasei Microsystems – Single-Chip Automatic Power/Temperature Control for WDM Laser Diodes

AKM Confidential
AK2571
5.2.2 Control registers
Figure 5-3 illustrates the register format. There are two areas in these registers, one is for AKM factory use and the other is
for user customization. Even though both areas are re-writable, the AKM values SHOULD NOT BE OVERWRITTEN.
If the AKM values are modified product functionality cannot be guaranteed.
Figure 5-3 Control Register
Self operation mode: Load the data from EEPROM to register
Register access mode: All data can be rewritable
R_CTRL_USER
R_CTRL_AKM
Register ^D7
D6
D5
D4
D3
D2
D1
D0
D7
D6
D5
D4
D3
D2
D1
D0
Apc_ Atc_ Apc_ Apc_ Atc_ _{Reserved Timer} Apc_ Atc_ Atc_
alm[4] alm[3] count[2] fb[1] fb[0] _{[7] [6]} main[5] lock[4] main[3]
Fix_cntl[2:0]
Atc_main / Atc_lock / Apc_main / Timer / Atc_fb / Apc_fb / Apc_cnt: 0: Disable 1: Enable
Atc_alm / Apc_alm: 0 ALM Enable, 1: ALM Disable
Fix_ctrl[2:000]0:: Start up or APC Count-up, Except000: Normal operation
EEPROM
Initial Status
User available area
Factory usage area by AKM
E_INI_CTRL_USER
E_INI_CNTL_AKM
X
X
X
0
1
0
1
1
0
0
0
APC Count-up
E_APC_CNT_CTRL_USER
E_APC_CNT_CTRL_AKM
X
X
0
1
1
0
1
0
0
0
Normal Operation
E_FIX_CTRL_USER
X
E_FIX_CTRL_AKM
0
1
1
0
1
1
1
1
X: Forbidden（Ignore the setting)
5.2.3 ATC Lock
1) When temperature data (R_TMPRT_CRNT) enters the target temperature range (R_TMPRT_TRGT) +/- hysteresis
(E_LK_TMPRT_WIN) ATC_LOCK_COUNTER starts to count up every 8mS.
2) Once temperature data is out of the range, ATC_LOCK_COUNTER is reset.
3) LD temperature is stabilized when ATC_LOCK_COUNTER reaches the settled value (E_LK_CNT_SET),. When
this happens, the AK2571 completes the ATC Lock sequence and moves to Status-2.
5.2.4 APC Count up
1) Increment the selected I -DAC value by one step (each 8mS) to prevent abrupt heat increases from affecting ATC.
2) Count up ends when the I-DACx selected by E_APC_CNT_SET (Count up DAC) reaches the target value
(E_APC_CNT_CTRL_USER[7:0]).
3) The unselected I-DAC retains the feed forward APC value if the Count up DAC doesn’t reach settled value.
4) Although the unselected DAC doesn’t reach its feed forward APC (or fixed) value, if count up DAC reaches to the
settled value, the AK2571 moves to Status-3
5.2.5 Timer
1) Counts the time from power on reset or release of shut down.
2) If the AK2571 does not reach normal operation within the period set by the settling time register (E_TIMER_SET), ,
TIMERALM is output.
<Rev. 0.6E Preliminary>
-24-
2001/11