LTC3206 Datasheet, PDF (6/16 Pages) Linear Technology – I2C Multidisplay LED Controller

LTC3206
BLOCK DIAGRA
C1⁺
C1^–
C2⁺
C2^–
5
4
6
3
V_IN 15
960kHz
OSCILLATOR
1x AND 1.5x CHARGE PUMP
25 PGND
14 CPO
ENABLECP
I_MS 11
I_RGB 12
SGND 13
2
2
2
22 MAIN1
21 MAIN2
20 MAIN3
19 MAIN4
23 AUX1
24 AUX2
1 SUB1
2 SUB2
DV_CC 7
ENRGB/S 10
SDA 8
SCL 9
CONTROL
LOGIC
4
4
PWM
444
STOP
COMMAND LATCH
24
I²C SERIAL PORT
16 RED
17 GREEN
18 BLUE
U
OPERATIO
Power Management
To optimize efficiency, the power management section of
the LTC3206 provides two methods of supplying power to
the CPO pin: 1x direct connect mode or 1.5x boost mode.
When any display of the LTC3206 is enabled, the power
management system connects the CPO pin directly to V_IN
with a low impedance switch. If the voltage supplied at V_IN
is high enough to power all of the LEDs with the pro-
grammed current, the system will remain in this “direct
connect” mode providing maximum efficiency. Internal
6
3206 BD
circuits monitor all current sources for the onset of “drop-
out,” the point at which the current sources can no longer
supply programmed current. As the battery voltage falls,
the LED with the largest forward voltage will reach the drop-
out threshold first. When any of the LED pins reach the drop-
out threshold, the LTC3206 will switch to boost mode and
automatically soft-start the 1.5x boost charge pump. The
constant frequency charge pump is designed to minimize
the amount of noise generated at the V_IN supply.
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