IRS20955STRPBF International Rectifier, IRS20955STRPBF Datasheet - Page 16

• 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

Supplying V
V
Zener diode clamp. I
can be estimated by:
I
0.5 mA + 0.5 mA
(Static) (Zener bias)
The value of R
following requirement:
Example: In the case where the average PWM
switching frequency is 400 kHz, the required I
1.18 mA. Based on this calculation, a 50 V power
supply voltage would require R
less.
Furthermore, make sure I
zener diode bias current, I
conditions.
Charging V
The high-side bootstrap capacitor can be charged
through a resistor from the positive supply bus to the
V
between V
need to charge the boot strap capacitor through low-
side turn on during start-up.
www.irf.com
DD
PWM
DD
B
pin by utilizing an internal 20.4 V Zener diode
≈ 1.5 mA x 300 x 10
is designed to be supplied with an internal
(Dynamic
B
Figure 18. Supplying V
BS
DD
and V
I
DDZ
Prior to Start
DD
CSD
VDD
VSS
VREF
OCSET
DT
IN
NC
R
used to supply I
DD
≥
IRS20955S
≤
V
S
+
. This scheme eliminates the
V
10.2V
DD
B
+
Rdd
B
−
, the supply current for V
−
10
I
-9
10
DD
COM
CSH
DD
VCC
power
2 .
HO
NC
LO
VS
VB
x switching frequency +
2 .
DDZ
V
Rdd
is below the maximum
V
−
, during static state
0
DD
[Ω]
DD
5 .
mA
DD
to be 33 kΩ or
should meet the
consumption)
DD
DD
12V
+B
Vcc
-B
is
,
The value of this charging resistor is subject to
several constraints:
Start-up Sequence (UVLO)
The protection control block in the IRS20955S
monitors the status of V
both voltage supplies are above the UVLO (under-
voltage lockout) threshold before beginning normal
operation. If either V
voltage threshold, LO and HO are disabled in
shutdown mode until both V
the voltage threshold.
Power-down Sequence
As soon as V
threshold, protection logic in the IRS20955S turns
off LO and HO, shutting off the power MOSFETs.
Figure 19. Boot Strap Supply Pre-charging
Figure 20. IRS20955 UVLO Timing Chart
-
-
The minimum value of R
the leakage current of the bootstrap voltage
supply through
the maximum PWM modulation index of the
system.
The maximum value of R
the current charge capability of the resistor
during startup:
where I
R
current.
I
CHARGE
CHARGE
>
DD
I
I
CHARGE
QBS
QBS
or V
IRS20955(S)PbF
DD
= the high side quiescent
RCHARGE
CC
or V
DD
=
and V
falls below the UVLO
DD
the
CC
, which would limit
and V
is below the under
CHARGE
CHARGE
CC
current
to ensure that
CC
is limited by
is limited by
rise above
16
through