ISL78229 Datasheet, PDF (63/71 Pages) Intersil Corporation – 2-Phase Boost Controller with Drivers

ISL78229
CC_LIMIT (D5h)
Definition: Set/Read the reference voltage V_{REF_CC} for constant current control loop described in “Constant Current Control (CC)” on
page 37. At overloading condition when constant current control loop is working, the V_IMON is controlled to be equal to the 1.6V reference
(V_{REF_CC}) by default. Since V_IMON represents the boost total input average current I_IN as described in “Average Current Sense for 2 Phases -
IMON” on page 32, the I_IN is controlled to be constant by the CC loop.
This command can set CC reference to 8 options ranging from 1.25V to 1.6V with default setting of 1.6V.
From Equations 13 and 14, Equation 33 can be derived to convert the 8 CC reference options in below table (as V_IMON in the equation)
to the actual total boost input current thresholds for CC, where COMMAND in the equation is the voltage options (CC_LIMIT Reference
Voltage) in the command table shown in following.
I_IN
=


C_-----O_---R--M_---I-M--M_---O--A_---N--N_-----D_--
–
17

10^–6_
 _R-^R----_SS----_EE----_NT--  8
(EQ. 33)
For related description, refer to “Constant Current Control (CC)” on page 37.
Data Length in Bytes: 1
Data Format: Bit Field
Type: R/W
Protectable: Yes
Default Value: 07h, which equals to 0000_0111b, meaning V_{REF_CC} = 1.6V (per table ) for V_IMON to follow at CC control.
Units:
V (referred for the reference voltage V_{REF_CC} for V_IMON to follow);
A (referred for the boost average input current converted by Equation 33)
COMMAND
Format
Bit Position
Access
Function
Default Value
7
R/W
0
6
R/W
0
5
R/W
0
CC_LIMIT (D5h)
Bit Field
4
3
R/W
R/W
See Following Table
0
0
2
R/W
1
1
R/W
1
0
R/W
1
BITS 7:3
(NOT USED)
Not Used
Not Used
Not Used
Not Used
Not Used
Not Used
Not Used
Not Used
BITS 2:0
000
001
010
011
100
101
110
111
CC REFERENCE VOLTAGE V_{REF_CC} (V)
1.25
1.3
1.35
1.4
1.45
1.5
1.55
1.6
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FN8656.3
February 12, 2016