SI8233 Datasheet, PDF (30/57 Pages) Silicon Laboratories – 0.5 AND 4.0 AMP ISODRIVERS

Si823x
4. Applications
The following examples illustrate typical circuit configurations using the Si823x.
4.1. High-Side/Low-Side Driver
Figure 43A shows the Si8230/3 controlled using the VIA and VIB input signals, and Figure 43B shows the Si8231/4
controlled by a single PWM signal.
OUT1
OUT2
CONTROLLER
VDDI
VDDI
C1
C2
1 µF
0.1 µF
GNDI
VDD2 D1
C3
1 µF
1500 V max
VDDA
VIA
VOA
VIB
DT
GNDA
RDT
Si8230/3
CB
Q1
VDDB
C4
C5
0.1 µF 10 µF
I/O
DISABLE
GNDB
VDDB
Q2
VOB
VDDI
VDDI
C1
C2
1 µF
0.1 µF
GNDI
PWMOUT
PWM
VDD2 D1
C3
1 µF
VDDA
1500 V max
VOA
CB
Q1
CONTROLLER
DT
GNDA
RDT
Si8231/4
VDDB
C4
C5
0.1 µF 10 µF
I/O
DISABLE
GNDB
Q2
VOB
A
B
Figure 43. Si823x in Half-Bridge Application
For both cases, D1 and CB form a conventional bootstrap circuit that allows VOA to operate as a high-side driver
for Q1, which has a maximum drain voltage of 1500 V. The boot-strap start up time will depend on the CB cap
chosen. See “AN486: High-Side Bootstrap Design Using Si823x ISODrivers in Power Delivery Systems”. VOB is
connected as a conventional low-side driver, and, in most cases, VDD2 is the same as VDDB. Note that the input
side of the Si823x requires VDD in the range of 4.5 to 5.5 V (2.7 to 5.5 V for Si8237/8), while the VDDA and VDDB
output side supplies must be between 6.5 and 24 V with respect to their respective grounds. It is recommended
that bypass capacitors of 0.1 and 1 µF value be used on the Si823x input side and that they be located as close to
the chip as possible. Moreover, it is recommended that 0.1 and 10 µF bypass capacitors, located as close to the
chip as possible, be used on the Si823x output side to reduce high-frequency noise and maximize performance.
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Rev. 1.7