LTC3216 Datasheet, PDF (5/12 Pages) Linear Technology – 1A Low Noise High Current LED Charge Pump with Independent Torch/Flash Current Control

LTC3216
PI FU CTIO S
C2⁺, C1⁺, C2^–, C1^– (Pins 1, 2, 10, 12): Charge Pump
Flying Capacitor Pins. A 2.2µF X5R or X7R ceramic
capacitor should be connected from C1⁺ to C1^– and from
C2⁺ to C2^–.
CPO (Pin 3): Output. CPO is the output of the Charge
Pump. This pin may be enabled or disabled using the EN1
and EN2 inputs. A 4.7µF X5R or X7R ceramic capacitor is
required from CPO to GND.
I_SET1/I_SET2 (Pins 4, 6): LED Current Programming Resis-
tor Pins. The I_SET1 and I_SET2 pins will servo to 1.22V.
Resistors connected between each of these pins and GND
are used to set the high and low LED current levels.
Connecting a resistor of 2kΩ or less will cause the
LTC3216 to enter overcurrent shutdown mode.
I_LED (Pin 5): Output. I_LED is the LED current source output.
The LED is connected between CPO (anode) and I_LED
(cathode). The current into the I_LED pin is set via the EN1
and EN2 inputs, and the programming resistors con-
nected from I_SET2 and I_SET1 to GND.
EN1/EN2 (Pins 7, 8): Inputs. The EN1 and EN2 pins are
used to select which current level is being supplied to the
LED, as well as to put the part into shutdown mode. The
truth table for these pins is as follows:
Truth Table
EN1
EN2
0
0
1
0
0
1
1
1
MODE
Shutdown
Low Current
High Current
Low + High Current
V_IN (Pin 9): Power. Supply voltage for the LTC3216. V_IN
should be bypassed with a 2.2µF or greater low impedance
ceramic capacitor to GND.
GND (Pin 11): Charge Pump Ground. This pin should be
connected directly to a low impedance ground plane.
EXPOSED PAD (Pin 13): Control Signal Ground. This pad
must be soldered to a low impedance ground plane for
optimum thermal and electrical performance.
BLOCK DIAGRA
C1⁺
C1^–
C2⁺
C2^–
2
12
1
10
OSCILLATOR
V_IN 9
EN2 8
EN1 7
CONTROL
LOGIC
11
GND
1X MODE: CPO = V_IN
1.5X MODE: CPO = 4.6V
2X MODE: CPO = 5.1V
3 CPO
V_REF
MODE
CONTROL
DROPOUT
DETECTOR
5 I_LED
CURRENT
SOURCE
CONTROL
6
4
13
I_SET2 I_SET1 GND
3216 BD
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