ASAHI KASEI
[AK2573A]
3.2 Duty Adjustment
AK2573A supplies a programmed duty adjustment in response to the temperature from an on-chip temperature
sensor (every 6℃, Duty data is stored in E_DUTY_TC, see Table 8-3 for more information). Write same data into
E_DUTY_TC for constant duty adjustment. Table 3-3 and 3-4 show the characteristics of duty adjustment function.
Table 3-3 Duty Adjustment characteristics
Item
Symbol
min
Maximum Pulse Extended
Td
0.5
1 LSB Pulse Extended Step
Tstep
Pulse Extended Stability
Tsta
typ
0.03
0.2
max
Unit
ns
ns
ns
Remarks
Note 1
32 Steps
Ta=-40 to 85℃, VDD=3.1�½�
3.5V, 0.3ns Extended (Note 1)
Note 1: This parameter is characterized and is not 100% tested.
Table 3-4 Pulse Extended
R_DUTY
Pulse Extended (typ) [ns]
0
0
1
0.03
2
0.06
.
.
.
.
30
0.90
31
0.93
Remark
4. APC
The AK2573A has two APC functions, APC FF (Feed-forward) and APC FB (Feedback).
APC FF supplies a programmed current in response to the temperature from an on-chip temperature sensor.
APC_FB provides stable a power control function using a digital feedback algorithm. The APC_FF and APC_FB is
user programmable. Fig4-1 illustrates APC block diagram.
Fig 4-1 APC Block Diagram
ALM Polarity
(RE_ALM_POL)
Temperature ALM
(RE_TEMPALM)
TEMP
ALM
Gain
(RE_DAC1_GAIN)
APC FF
(R_DAC1_FF)
TEMPSN
S
ADC
R_TEMP
EEPROM
K_DAC1
_FBRT
APC FB Operation
(RE_APC_FB_SET)
TEMPMON
APC Operation
(RE_APC_FF_SET)
K_DAC2
_FBRT
+
R_DAC2
* 0.0095
APC Feedback
(R_APC_FB)
ALMPolarity
(RE_ALM_POL)
R_DAC1
R_DAC2
Over current ALM
(RE_CURRALM)
ALM Polarity
(RE_ALM_POL)
OPTALM
OPTALM Reference
(optalm_ref)
OPTALM
BIASMON
R_DAC1
Imod
I-DAC1
Driver
IMODN
I-DAC1 FB
(R_DAC1_FB)
I-DAC2 FB
(R_DAC2_FB)
* 0.0095
MODMO
Gain
N
(RE_DAC2_GAIN)
Ibias IBIAS
APC FF
(R_DAC2_FF)
I-DAC2
TEMPALM
RE_TEMP_OFFSET
IMOD
+
APC FB Initial setting
(RE_APC_INIT_SET)
PDMON
Monitor
PD
PDIN
CPD
RPD
PDGAIN
(RE_PDGAIN)
APC_
COMP
Digital Filter
apc_comp_out
vpd
1/N
1/s
CURR
ALM
CURRALM
PDGAIN
OPTALM
(RE_OPTALM_)
APC Target
(RE_APC_TRGT)
DAC_APC
vapc_ref
ATT
<MS0189-E-01>
-14-
2004/5
AKM [ ASAHI KASEI MICROSYSTEMS ]
