Analog Devices ADP1660 Evaluation Board ADP1660CB-EVALZ ADP1660CB-EVALZ Ficha De Dados
Códigos do produto
ADP1660CB-EVALZ
ADP1660
Data Sheet
Rev. 0 | Page 14 of 28
BATTERY INPUT DC CURRENT LIMIT
has an optional programmable input dc current
limit that limits the maximum battery current used over all con-
ditions. This feature allows higher LED currents to be used in a
system with significant variation in LED forward voltage (V
ditions. This feature allows higher LED currents to be used in a
system with significant variation in LED forward voltage (V
F
) and
supply battery voltage without the risk of exceeding the current
allocated to the flash. To enable the input dc current limit, set
the IL_DC_EN bit (Bit 0) in Register 0x03. To set the input dc
current limit, use the IL_DC bits (Bits[3:1]) in Register 0x03
(see Table 10).
allocated to the flash. To enable the input dc current limit, set
the IL_DC_EN bit (Bit 0) in Register 0x03. To set the input dc
current limit, use the IL_DC bits (Bits[3:1]) in Register 0x03
(see Table 10).
Table 10. Input DC Current Limit
IL_DC Bit Value
DC Current Limit (A)
000 1.0
001 1.25
010 1.5
011 1.75
100 2.0
001 1.25
010 1.5
011 1.75
100 2.0
(default)
101 2.25
110 2.5
111 2.75
110 2.5
111 2.75
During startup of the flash, if the battery current does not
exceed the dc current limit, the LED1 and LED2 currents are
set to the values of the I_FL1 and I_FL2 bits in Register 0x06
and Register 0x09, respectively.
exceed the dc current limit, the LED1 and LED2 currents are
set to the values of the I_FL1 and I_FL2 bits in Register 0x06
and Register 0x09, respectively.
If the battery current exceeds the programmed dc current limit
on startup, the LED current does not increase further. The dc
current limit flag is set in the fault information register (Bit 0
of Register 0x0C). The FL_I_FL1 bits in Register 0x0D and the
FL_I_FL2 bits in Register 0x0E are set to the actual LED current
values and are available for readback.
on startup, the LED current does not increase further. The dc
current limit flag is set in the fault information register (Bit 0
of Register 0x0C). The FL_I_FL1 bits in Register 0x0D and the
FL_I_FL2 bits in Register 0x0E are set to the actual LED current
values and are available for readback.
REG 0x02, FL_TIM = XXXXms
REG 0x06, I_FL1 = XX XXXXmA
REG 0x09, I_FL2 = XX XXXXmA
REG 0x09, I_FL2 = XX XXXXmA
REG 0x03, IL_DC_EN = 1
IL_DC = XX A
I
2
C DATA BUS
STROBE
PROGRAMMED LED CURRENT
ACTUAL LED CURRENT
ADP1660 SETS FL_IDC (REG 0x0C) TO 1.
ADP1660 SETS FL_I_FL1 (REG 0x0D)
TO ACTUAL LED CURRENT.
ADP1660 SETS FL_I_FL1 (REG 0x0D)
TO ACTUAL LED CURRENT.
ADP1660 SETS LED1_EN TO 0.
ADP1660 SETS LED2_EN TO 0.
ADP1660 SETS LED_MOD TO 000.
ADP1660 SETS LED2_EN TO 0.
ADP1660 SETS LED_MOD TO 000.
REG 0x0F, LED1_EN = 1
LED2_EN = 1
REG 0x01, STR_LV = 1
LED_MOD = 011
ADP1660 SETS FL_I_FL2 (REG 0x0E)
TO ACTUAL LED CURRENT.
TO ACTUAL LED CURRENT.
1
10
18-
020
Figure 25. DC Current Limit Operation in a Low Battery, High LED V
F
Case
The camera system shown in Figure 26 can adjust the image
sensor settings based on the known reduced LED current for
a low battery and a high V
sensor settings based on the known reduced LED current for
a low battery and a high V
F
LED.
SELECT FLASH CURRENT
SELECT MAX BATTERY CURRENT
PREFLASH STROBE
DC LIMIT
EXCEEDED?
LED CURRENT =
PROGRAMMED LED
CURRENT
NO
LED CURRENT LOCKED
AT CURRENT VALUE
YES
BATTERY CURRENT =
PROGRAMMED DC LIMIT
READ LED CURRENT
(REG 0x0D AND REG 0x0E)
ADJUST IMAGE SENSOR
STROBE
STROBE
11
018
-021
Figure 26. Use of the DC Current Limit in an Optimized Camera System