IRS20955STRPBF International Rectifier, IRS20955STRPBF Datasheet - Page 11

• Manufacturer Part Number: IRS20955STRPBF
• Description: IC DVR DGTL AUDIO PROT 16-SOIC
• Manufacturer: International Rectifier
• Type: MOSFET Driverr

Specifications of IRS20955STRPBF

• Applications: Amplifiers, Receivers
• Mounting Type: Surface Mount
• Package / Case: 16-SOIC (3.9mm Width)
• For Use With: IRAUDAMP4 - KIT 2CH 120W HALF BRDG AUDIO AMP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Shutdown Input
When V
to charge C
Once the voltage of the CSD pin rises above the
upper threshold,
normally again.
Latched Protection
Connecting CSD to V
resistor configures the over-current protection latch.
The latch locks the IC in shutdown mode after over-
current is detected. An external reset switch can be
used to bring CSD below the lower threshold
a minimum of 200 ns to properly reset the latch.
After the power up sequence, a reset signal to the
CSD pin is required to release the IC from shutdown
mode.
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Figure 10. Latched Protection Configuration
CSD
RESET
SHUTDOWN
Figure 9. Shutdown Input
falls below V
t
in an attempt to resume operation.
V
th1
<10k
, the IC begins to operate
DD
th2
through a 10 kΩ or less
, the IRS20955S begins
VDD
CSD
VREF
OCSET
VSS
NC
VDD
CSD
VREF
OCSET
IN
DT
VSS
NC
DT
IN
CSH
VCC
COM
CSH
VCC
HO
VS
NC
LO
COM
VB
HO
NC
VB
VS
LO
V
th2
for
Interfacing with System Controller
The IRS20955S can communicate with an external
system controller through a simple interfacing circuit
such as the one shown in Figure 11. A generic PNP
transistor, shown as U1, can detect the sink current
at the CSD pin during an OCP event and output a
shutdown signal to an external system controller.
Another generic NPN transistor, shown as U2, can
then reset the internal protection logic by pulling the
CSD voltage below V
Note that the CSD pin is configured to operate in
latched OCP. After the power up sequence, a reset
signal to the CSD pin is required to release the IC
from shutdown mode.
Programming OCP Trip Level
In a Class D audio amplifier, the direction of the load
current alternates with the audio input signal. An
over-current condition can therefore occur during
either a positive current cycle or a negative current
cycle. The IRS20955 uses the R
MOSFETs as current sensing resistors. Due to the
structural constraints of high voltage ICs, current
sensing is implemented differently for high side and
low side. If the measured current exceeds a
predetermined threshold, the OCP block outputs a
signal to the protection block to shutdown the
MOSFET to protect the switching devices.
Figure 11. Interfacing with System Controller
IRS20955(S)PbF
th2
for a minimum of 200 ns.
DS(ON)
of the output
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