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| CAT4101_12 Datasheet, PDF (7/9 Pages) ON Semiconductor – 1 A Constant-Current LED Driver | |||
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CAT4101
Block Diagram
VIN
LED
VIN
Undervoltage & Thermal
Lockout
EN/PWM
Shutdown Delay
RSET
Reference Voltage
RSET Regulator & Mirror
Current
Regulator
GND
Figure 15. CAT4101 Functional Block Diagram
Basic Operation
The CAT4101 has one highly accurate LED current sink
to regulate LED current in a string of LEDs. The LED
current is mirrored from the current flowing from the RSET
pin. Table 6 lists various RSET resistor values for LED
current in 100 mA increments.
The LED channel needs a minimum of 500 mV headroom
to sink constant regulated current. If the input supply falls
below 2 V, the underâvoltage lockout circuit disables the
LED channel.
For applications requiring current higher than 1 A, several
CAT4101 devices can be connected in parallel.
The LED channel can withstand and operate at voltages
up to 25 V. This makes the device ideal for driving long
strings of high power LEDs from a high voltage source.
Table 6. RSET RESISTOR SETTINGS
LED Current [mA]
RSET [W]
100
4990
200
2490
300
1690
400
1270
500
1050
600
866
700
768
800
680
900
604
1000
549
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