CAT3604VHV4-GT2 CATALYST SEMICONDUCTOR, CAT3604VHV4-GT2 Datasheet - Page 10

• Manufacturer Part Number: CAT3604VHV4-GT2
• Description: IC, LED DRIVER, CHARGE PUMP, TQFN-16
• Manufacturer: CATALYST SEMICONDUCTOR

Specifications of CAT3604VHV4-GT2

• Led Driver Application: LCD Display Backlight, Digital Still Cameras
• No. Of Outputs: 4
• 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 400 ms). In 1.33x mode, the output voltage is
approximately equal to 1.33 times the input supply voltage
(less any internal voltage losses).
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 500 mV
LED Current Selection
follows:
At power−up, the CAT3604V starts operating in 1x mode
If the input voltage is insufficient or falls to a level where
This sequence repeats in the 1.33x and 1.5x mode until the
If the device detects a sufficient input voltage is present to
The LED current is set to by the external resistor RSET as
LED current + 132
V
IN
RSET
VIN
EN
Figure 25. CAT3604V Functional Block Diagram
0.6 V
R
SET
1.33x, 1.5x, 2x Charge Pump
C
1−
1, 1.3 MHz
Reference
Oscillator
Current
Setting
Voltage
1x mode (LDO)
C
1+
HYS
http://onsemi.com
) and
C
2−
Mode Control
10
C
driver enters a “zero current” shutdown mode if EN is held
low for 1.5 ms or more.
instantly disabled, where the LED current is set to zero. As
long as the CAT3604V is not in shutdown mode, the LEDs
turn on as soon as the EN goes high.
Unused LED Channels
recommended to connect the unused LED pins directly to
VOUT (see Figure 26).
Protection Mode
diagnostics, then ignores that channel and goes back to the
most effective mode. When all LEDs are disconnected, the
ON OFF
R
2+
V
SET
The EN pin enables and disables the device. The LED
As soon as the EN input goes low, all LED channels are
For applications not requiring all the channels, it is
If an LED is disconnected, the device senses that, run the
IN
1 mF
C
IN
GND
Figure 26. Application with 3 LEDs
RSET
VIN
EN
C1+
CAT3604V
1 mF
C1−
VOUT
LED Channel
Current Regulators
GND
LED1
LED2
LED3
LED4
C2+
VOUT
LED1
LED2
LED3
LED4
1 mF
C2−
C
1 mF
OUT