LTC3212
1
DESCRIPTION
WARNING!
Do not look directly at operating LED.
This circuit produces light that can damage eyes.
Demonstration circuit 1187 is an RGB LED Driver
and Charge Pump featuring the LTC3212.
The LTC3212 is a low noise charge pump capable
of driving three LEDs up to 25mA each. This de-
vice requires only one flying capacitor, two by-pass
capacitors, and one to three programming resis-
tors. Each LED may be turned on individually, in
combination with each other, or in white mode us-
ing a single wire interface. White mode optimizes
the red, green, and blue current settings to provide
the best white color.
LED currents are regulated using internal low
dropout current sources. Automatic mode switch-
ing optimizes efficiency by switching modes only
when a dropout is detected. Refer to the LTC3212
datasheet for more information on this device.
Design files for this circuit board are available.
Call the LTC factory.
L
, LTC, LTM, and LT are registered trademarks of Linear Technology Corporation.
Other product names may be trademarks of the companies that manufacture the
products.
PERFORMANCE SUMMARY
Specifications are at T
A
= 25°C
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
Input Supply Range
2.7
5.5
V
I
VIN
Shutdown Current
LEDEN = LOW
3
8
µA
I
VIN
Operating Current
ICPO
= 0mA, 1X Mode
ICPO
= 0mA, 2X Mode
0.4
2.0
mA
mA
I
LED
R
ISET
= 33.87K
Ω
(Not in White Mode)
R
ISET
= 58.87K
Ω
(Not in White Mode)
R
ISET
= 8.87K
Ω
(Not in White Mode)
5.24
3.0
20.0
mA
mA
mA
I
LEDG
(WHITE MODE)
R
ISETG
= 33.87K
Ω
R
ISETG
= 58.87K
Ω
R
ISETG
= 8.87K
Ω
5.24
3.0
20.0
mA
mA
mA
I
LEDB
(WHITE MODE)
R
ISETG
= 33.87K
Ω
R
ISETG
= 58.87K
Ω
R
ISETG
= 8.87K
Ω
3.93
2.62
15.0
mA
mA
mA
I
LEDR
(WHITE MODE)
R
ISETG
= 33.87K
Ω
R
ISETG
= 58.87K
Ω
R
ISETG
= 8.87K
Ω
4.72
2.71
18.0
mA
mA
mA
I
LED
Dropout Voltage (V
ILED
)
Mode Switching Threshold, I
LED
= 15mA
150
mV
Charge Pump Output Clamp Voltage
5.1
V
I
CPO
0
75
mA
DEMO CIRCUIT 1187
QUICK START GUIDE
LTC3212
RGB LED Driver and
Charge Pump
Summary of Contents for LTC3212
Page 6: ...LTC3212 6...
Page 7: ...LTC3212 7...
