CAT3647HV3-GT2 CATALYST SEMICONDUCTOR, CAT3647HV3-GT2 Datasheet - Page 10

• Manufacturer Part Number: CAT3647HV3-GT2
• Description: IC, LED DRIVER, CHARGE PUMP, TQFN-16
• Manufacturer: CATALYST SEMICONDUCTOR

Specifications of CAT3647HV3-GT2

• Led Driver Application: LCD Display Backlight, Digital Still Cameras
• No. Of Outputs: 3
• Output Current: 30mA
• Output Voltage: 7V
• Input Voltage: 2.5V To 5.5V
• Topology: Charge Pump
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Block Diagram
Basic Operation
where the output will be approximately equal to the input
supply voltage (less any internal voltage losses). If the
output voltage is sufficient to regulate all LED currents, the
device remains in 1x operating mode.
the regulated currents cannot be maintained, the device
automatically switches into 1.33x mode (after a fixed delay
time of about 120 ms). In 1.33x mode, the output voltage is
approximately equal to 1.33 times the input supply voltage
(less any internal voltage losses).
At power-up, the CAT3647 starts operating in 1x mode
If the input voltage is insufficient or falls to a level where
VIN
EN/DIM
100 kΩ
Registers
Interface
Serial
Figure 24. CAT3647 Functional Block Diagram
1.33x, 1.5x, 2x Charge Pump
C1+
Setting DAC
1, 1.3 MHz
Reference
Oscillator
Current
Voltage
1x mode (LDO)
C1−
RSET
http://onsemi.com
C2−
10
Mode Control
driver enters the 2x mode. In 1.5x mode, the output voltage
is approximately equal to 1.5 times the input supply voltage.
While in 2x mode, the output is approximately equal to 2
times the input supply voltage.
drive all LED currents in 1x mode, it will change
automatically back to 1x mode. This only applies for
changing back to the 1x mode. The difference between the
input voltage when exiting 1x mode and returning to 1x
mode is called the 1x mode transition hysteresis (V
is about 400 mV.
C2+
This sequence repeats in the 1.33x and 1.5x mode until the
If the device detects a sufficient input voltage is present to
GND
LED Channel
Current Regulators
VOUT
LED1
LED2
LED3
HYS
) and