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ILD8150 80 V high side buck LED driver IC with hybrid dimming
Circuit description
2
Circuit description
2.1
Operation
Typical application circuit
Figure 1
2.1.1
Current regulation
Figure 1 shows the typical application circuit. Current is controlled by the CS pin, which compares the voltage
drop on R
to internal references. Output current is proportional to the voltage drop on R
CS
voltage drops below V
CSL
voltage achieves V
the MOSFET switches off, and stored energy in inductor L discharges through the diode D.
CSH
In this way, the system maintains a constant average output current as shown in Figure 2.
Current regulation
Figure 2
Current never goes down to zero, so the system operates in Continuous Conduction Mode (CCM), where
Application Note
C
VCC
SD
Vsd
DIM
V
DIM
the MOSFET switches on. Current and voltage on R
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The output ripple of the instantaneous current is:
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I
[A]
OUT
I
LED,AVG
1/f
Cin
VCC
VIN
BOOT
L
Cboot
SW
Iout
D
IC
Cout
Rfltr
CS
Cfltr
GND
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=
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t
t
SW
ON
OFF
4 of 28
Vin
Vout
Rcs
. When the CS
CS
rise accordingly. When the CS
CS
I
OUT
time [s]
V 1.0
2019-01-23
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