LTC3206
W
BLOCK DIAGRA
+
–
+
–
C1
5
C1
4
C2
6
C2
3
960kHz
OSCILLATOR
25 PGND
CPO
14
V
IN
15
1x AND 1.5x CHARGE PUMP
–
+
ENABLECP
MAIN1
MAIN2
MAIN3
MAIN4
22
21
20
19
+
–
I
11
MS
AUX1
AUX2
23
24
+
–
2
2
I
12
13
RGB
SUB1
SUB2
1
2
SGND
2
DV
CC
7
CONTROL
LOGIC
RED
16
17
18
ENRGB/S
10
PWM
GREEN
BLUE
4
4
4
4
4
COMMAND LATCH
24
STOP
SDA
SCL
8
9
2
I C SERIAL PORT
3206 BD
U
OPERATIO
Power Management
To optimize efficiency, the power management section of circuits monitor all current sources for the onset of “drop-
the LTC3206 provides two methods of supplying power to out,” the point at which the current sources can no longer
the CPO pin: 1x direct connect mode or 1.5x boost mode. supply programmed current. As the battery voltage falls,
When any display of the LTC3206 is enabled, the power theLEDwiththelargestforwardvoltagewillreachthedrop-
management system connects the CPO pin directly to VIN outthresholdfirst.WhenanyoftheLEDpins reachthedrop-
with a low impedance switch. If the voltage supplied at VIN out threshold, the LTC3206 will switch to boost mode and
is high enough to power all of the LEDs with the pro- automatically soft-start the 1.5x boost charge pump. The
grammed current, the system will remain in this “direct constant frequency charge pump is designed to minimize
connect” mode providing maximum efficiency. Internal the amount of noise generated at the VIN supply.
3206f
6
Linear [ Linear ]
