cat3604 Catalyst Semiconductor, cat3604 Datasheet - Page 4

• Manufacturer Part Number: cat3604
• Description: 4-channel Regulated Charge Pump White Led Driver
• Manufacturer: Catalyst Semiconductor

CAT3604
BASIC OPERATION
At power-up, the CAT3604 starts operation in 1x
mode. If it is able to drive the programmed LED
current, it continues in 1x mode. If the battery
voltage drops to a level where the LED current
cannot be met, the driver automatically switches
into 1.5x mode. The 1.5x charge pump will boost
the output voltage accordingly to achieve the nomi-
nal LED current.
BLOCK DIAGRAM
Doc. No. 5008, Rev. I
Battery
3<VIN<4.2V
RSET
C IN
VIN
CTR0
CTR1
CTR2
EN
1.2V Ref
Current
Output
Setting
Select
LED
Figure 1: CAT3604 Functional Block Diagram
C1-
Oscillator
1MHz
1.5x Charge Pump
1x mode (LDO)
C1+
C2-
4
Mode Control
The operating mode is reinitialized each and every
time the chip is powered up or is taken out of
shutdown mode (via EN pin). The use of the control
pins (CTR0, CTR1, CTR2) does not reconfigure the
mode of operation.
C2+
4 Current
Sink Regulators
LED1
LED2
LED3
LED4
VOUT
Characteristics subject to change without notice
© Catalyst Semiconductor, Inc.
20mA
C OUT