CAT3604_08 Datasheet, PDF (5/12 Pages) Catalyst Semiconductor – 4-Channel Regulated Charge Pump White LED Driver

CAT3604
LED CURRENT SETTING
The LED current is set by the external resistor R_SET
connected between the RSET pin and ground. Table 1
lists various LED currents and the associated R_SET
resistor value for standard 1% precision surface mount
resistors.
Table 1. RSET Resistor Selection
LED Current (mA)
1
2
5
10
15
20
30
R_SET (kΩ)
649
287
102
49.9
32.4
23.7
15.4
SHORT CIRCUIT DETECT/DISABLES
The unused LED channels can also be turned off by
connecting the respective LED pins to VOUT. In which
case, the corresponding LED driver is disabled and the
typical LED sink current is only about 20µA. When the
following equation is true on any channel, the driver
turns off the LED channel:
VOUT - V_LED ≤ 1V (LED channel OFF)
Note: The CAT3604 is designed to drive LEDs with
forward voltage greater than 1V and is not compatible
with resistive loads.
The digital control lines CTR0, CTR1 adn CTR2 allow to
turn On or Off a combition of LEDs as shown in Table 2.
Table 2: LED Selection
Control Lines
CTR2 CTR1 CTR0
0
0
0
0
0
1
0
1
0
0
1
1
1
0
0
1
0
1
1
1
0
1
1
1
LED4
–
–
–
ON
–
–
ON
–
LED Outputs
LED3 LED2
–
–
–
ON
ON
–
–
–
–
ON
ON ON
ON ON
–
–
LED1
ON
–
–
–
ON
ON
ON
–
Notes:
1 = logic high (or VIN)
0 = logic low (or GND)
– = LED output OFF
© Catalyst Semiconductor, Inc.
5
Characteristics subject to change without notice
Doc. No. MD-5008 Rev. J