SI823X Datasheet, PDF (29/52 Pages) Silicon Laboratories – 0.5 AND 4.0 AMP ISODRIVERS (2.5 AND 5 KVRMS)

Si823x
7. Applications
The following examples illustrate typical circuit configurations using the Si823x.
7.1. 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
I/O
VDDI
VDDI
VDD2 D1
C2
1 µF
C1
1uF
GNDI
VDDA
1500 V max
CB
VIA
VOA
Q1
VIB
DT
GNDA
RDT
Si8230/3
VDDB
VDDB
DISABLE
GNDB
C3
10uF
Q2
VOB
PWMOUT
CONTROLLER
I/O
VDDI
VDDI
C1
1uF
GNDI
PWM
VDD2 D1
C2
1 µF
VDDA
1500 V max
VOA
CB
Q1
DT
GNDA
RDT
Si8231/4
VDDB
VDDB
DISABLE
GNDB
C3
10uF
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. VOB is connected as a conventional low-side driver. Note
that the input side of the Si823x requires VDD in the range of 4.5 to 5.5 V, while the VDDA and VDDB output side
supplies must be between 6.5 and 24 V with respect to their respective grounds. The boot-strap start up time will
depend on the CB cap chosen. VDD2 is usually the same as VDDB. Also note that the bypass capacitors on the
Si823x should be located as close to the chip as possible. Moreover, it is recommended that 0.1 and 10 µF bypass
capacitors be used to reduce high frequency noise and maximize performance.
Rev. 0.3
29