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
Td
Tstep
Tsta
min
0.5
typ
max
0.2
Unit
ns
ns
Remarks
Maximum Pulse Extended
1 LSB Pulse Extended Step
Pulse Extended Stability
Note 1
32 Steps
0.03
ns
Ta=-40 to 85℃, VDD=3.1～
3.5V, 0.3ns Extended (Note 1)
Note 1: This parameter is characterized and is not 100% tested.
Table3-4 Pulse Extended
R_DUTY
Pulse Extended (typ) [ns] Remark
0
1
2
0
0.03
0.06
.
.
.
.
30
31
0.90
0.93
4. APC
The AK2573A has two APCfunctions, 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)
TEMPALM
TEMP
ALM
Gain
(RE_DAC1_GAIN)
RE_TEMP_OFFSET
IMOD
APC FF
(R_DAC1_FF)
Imod
R_DAC1
Driver
+
I-DAC1
TEMPSN
S
ADC
K_DAC1
_FBRT
EEPROM
IMODN
R_TEMP
I-DAC1 FB
(R_DAC1_FB)
* 0.0095
APC FB Operation
(RE_APC_FB_SET)
MODMO
N
Gain
APC Operation
(RE_APC_FF_SET)
TEMPMON
I-DAC2 FB
(R_DAC2_FB)
(RE_DAC2_GAIN)
K_DAC2
_FBRT
Ibias IBIAS
+
I-DAC2
APC FF
(R_DAC2_FF)
R_DAC2
APC FB Initial setting
(RE_APC_INIT_SET)
* 0.0095
ALMPolarity
(RE_ALM_POL)
BIASMON
APC Feedback
(R_APC_FB)
PDMON
R_DAC1
CURRALM
CURR
R_DAC2
ALM
Monitor
PD
PDGAIN
(RE_PDGAIN)
Digital Filter
apc_comp_out
Over current ALM
(RE_CURRALM)
PDIN
1/N
1/s
APC_
COMP
vpd
CPD
PDGAIN
RPD
ALM Polarity
(RE_ALM_POL)
OPTALM
(RE_OPTALM_)
OPTALM
OPTALM
APC Target
(RE_APC_TRGT)
DAC_APC
ATT
vapc_ref
OPTALM Reference
(optalm_ref)
<MS0189-E-01>
-14-
2004/5
AKM [ ASAHI KASEI MICROSYSTEMS ]
