IR21571S International Rectifier, IR21571S Datasheet - Page 13

• Manufacturer Part Number: IR21571S
• Description: IC BALLAST CONTROL 16-SOIC
• Manufacturer: International Rectifier
• Type: Ballast Controllerr

Specifications of IR21571S

• Frequency: 45.5 ~ 50.5 kHz
• Current - Supply: 5.5mA
• Current - Output: 500mA
• Voltage - Supply: 11.4 V ~ 15.6 V
• Operating Temperature: -40°C ~ 125°C
• Package / Case: 16-SOIC (3.9mm Width)
• Package: 16-lead SOIC Narrow
• Circuit: Fluorescent Ballast IC
• Offset Voltage (v): 625
• Output Source Current Min (ma): 250
• Output Sink Current Min (ma): 400
• Vcc Range (v): 10-25V with UVLO
• Output Voltage Min (v): 10
• Output Voltage Max (v): 25
• Special Ic: Fully Integrated
• Pbf: PbF Option Available
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Other names: *IR21571S

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The second protection lead, SD, is used for both
unlatched shutdown and automatic restart functions.
The SD lead would normally be connected to an
external circuit which senses the presence of the
lamp (or lamps), as shown in Figure 12.
When the SD lead exceeds 2.0V (approximately
150mV of hysteresis is included to increase noise
immunity), signaling either a lamp fault or lamp
removal, the oscillator is disabled, both gate driver
outputs are pulled low, and the chip is put into the
micropower mode. Since a lamp fault would normally
lead to a lamp exchange, when a new lamp is
inserted into the fixture, the SD lead would be pulled
back to near the ground potential. Under these
VDC
CT
CPH
LO
HO-VS
5
3
15
15
4
8
Lamp Presence Detection and
Figure 11: VDC lead fault and auto restart
RUN mode
Automatic Restart
Low VDC
Restart
conditions a reset signal would restart the chip from
the beginning of the control sequence, as shown in
the timing diagram in Figure 13.
VDC
CPH
RPH
RUN
OC
RT
CT
DT
SD
CT
CPH
LO
HO-VS
1
2
3
4
5
6
7
8
2
15
15
4
8
Figure 12: Lamp presence detection circuit
Figure 13: SD lead fault and auto restart
16
15
14
13
12
11
10
9
RUN mode
VCC
COM
HO
VS
VB
CS
SD
LO
IR21571 (S) & (PbF)
connection (shaded area)
+ rectified
AC Line
R
C
D
C
GHS
R3
BS
BOOT
VCC
C2
R4
R
GLS
V
R
BUS
Supply
R
SD mode
CS
+ V
return
BUS
R5
D1
C
C
D2
BLOCK
SNUBBER
Restart
L
RES
C
RES
13