FAN5607 Fairchild Semiconductor, FAN5607 Datasheet - Page 9

• Manufacturer Part Number: FAN5607
• Description: LED Driver with Adaptive Charge Pump DC/DC Converter
• Manufacturer: Fairchild Semiconductor

PRODUCT SPECIFICATION
Switch Configurations
Shutdown and Short Circuit Current Limit
Set both DAC inputs low to shut down the device. Built-in
short circuit protection limits the supply current to a maxi-
mum of 65mA.
LED Brightness Control Methods
R
The basic method is to use external resistor to set the LED
current. Connect the resistor with the appropriate value
between R
REV. 1.0.0 6/22/04
R
I
SET
LED
SET
Only-Analog
(mA)
(KΩ) 8.25
Figure 3. Step-up, 2:1 Configuration
SET
and GND to set the LED current.
30
V
IN
Switch positions shown in charge phase
Reverse all switches for pump phase
GND
12.5
20
25
10
50
5
V
OUT
=
62.5
4
2 X V
IN
Figure 4. Step-up, 3:2 Configuration
The resistor value establishes the reference current needed
for a constant LED current. Value of R
current are given in the table above and also in the graph
below, using the function: R
Switch positions shown in charge phase
Reverse all switches for pump phase
CAP2
CAP1
GND
35
30
25
20
15
10
5
0
V
+
+
-
IN
0
-
LED Current vs R
10
20
SET
30
R
SET
= 250/I
40
(KΩ)
V
C
OUT
OUT
SET
50
SET
LED
for a fixed LED
.
60
70
FAN5607
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