33883 Datasheet, PDF (17/21 Pages) Freescale Semiconductor, Inc – H-Bridge Gate Driver IC

FUNCTIONAL DEVICE OPERATION
PROTECTION AND DIAGNOSTIC FEATURES
V_CC
I _(C1+C2)
I_C1max
0A
t _C1min
V_{(LR_OUT)}
V_(C1)
0V
t _C1max
I _C1min
V_C1min
Figure 13. Limits of C1 Current and Voltage with Large Values of dV/dt
In the case of rapidly changing V_CC voltages, the large dV/
dt may result in perturbations of the high-side driver, thereby
forcing the driver into an OFF state. The addition of
capacitors C3 and C4, as shown in Figure 14, reduces the
dV/dt of the source line, consequently reducing driver
perturbation. Typical values for R3 / R4 and C3 / C4 are 10 Ω
and 10 nF, respectively.
DV/DT AT V_CC2
When the external high-side MOSFET is on, in case of
rapid negative change of V_CC2 the voltage (V_{GATE_HS} -
V_{SRC_HS}) can be higher than the specified 18 V. In this case
a resistance in the SRC line is necessary to limit the current
to 5.0 mA max. It will protect the internal zener placed
between GATE_HS and SRC terminals.
In case of high current (SRC_HS >100 mA) and high
voltage (>20 V) between GATE_HSX and SRC_HS an
external zener of 18 V is needed as shown in Figure 14.
Analog Integrated Circuit Device Data
Freescale Semiconductor
33883
17