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ILD8150 80 V high side buck LED driver IC with hybrid dimming
Circuit description
2.2.6
Shut-down
ILD8150 has a shut-down control pin SD. If the voltage on the pin is below low-threshold V
recognition time more than t
voltage on the pin is higher than threshold V
operation through the soft-start process. Floating SD is pulled up by an internal I
down, the current has to be more than I
2.2.7
Floating driver and bootstrap supply
The high-side MOSFET gate driver is supplied by the bootstrap circuit. Capacitor C
side MOSFET is switched off and the diode D conducts current from V
Where Q
is the internal MOSFET gate charge, 2.5 nC and ∆V
G
The internal supply circuit provides voltage to the bootstrap capacitor V
V
. This circuit helps to maintain the voltage in dim-to-off and standby conditions. Higher voltage improves the
CC
R
of the internal MOSFET.
ON
External bootstrap diode usage
Figure 9
The IC contains an internal bootstrap diode. An external high-speed signal or Shottky diode, with voltage
robustness higher than V
power dissipation at high switching frequency.
2.2.8
V
pin ESD protection
IN
The V
pin is protected by an internal ESD structure. If V
IN
slew ratio V/ns, which may happen at HV spikes, the ESD structure conducts and absorbs the ESD stress. If the
application is a DC-DC LED driver with very low input capacitance and permanent ESD stress, it is
recommended to use an external TVS diode, which protects the IC.
Application Note
the IC goes to shut-down mode with low self-consumption current. If the
SD_IL
during recognition time more than t
SD_IH
.
SD,LPU
��
C
VCC
SD
Vsd
DIM
V
DIM
, can be used between the V
IN
. C
CC
��
��
>
��������
∆��
����������
is voltage deviation on the bootstrap capacitor.
CBOOT
Cboot
Cin
Dboot
VCC
VIN
BOOT
L
Cboot
SW
Iout
D
IC
Cout
Rfltr
CS
Cfltr
GND
and BOOT pins as shown in Figure 9. This decreases IC
CC
exceeds the absolute maximum ratings with high-
IN
8 of 28
during
SD_IL
the IC resumes normal
SD_HI
current source. To pull it
SD,LPU
is charged when the high-
BOOT
can be calculated as:
BOOT
≈ 8.6 V, which is a little higher than
Vin
Vout
Rcs
V 1.0
2019-01-23
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