IR21571S International Rectifier, IR21571S Datasheet - Page 10

• 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

IR21571 (S) & (PbF)
tDEAD
10
(usec)
0.1
10
1
1
C
START
Figure 5: Deadtime versus R
R
C
R
T
C
IGN
START
T
Figure 6: Oscillator section block diagram with external component connection
C
PH
R
RDT (Kohms)
R
RUN
R
PH
DT
10
RUN
CPH
RPH
RT
CT
DT
2
3
4
5
6
7
7.6V
DT
CT = 220 pF
CT = 470 pF
CT = 1 nF
I
CT
I
= I
RT
5.1V
4.0V
RT
1.0uA
100
2.0V
During the Startup Mode, the operating frequency is
determined by the parallel combination of R
R
C
normally chosen to ensure that the instantaneous
voltage across the lamp during the first few cycles of
operation does not exceed the strike potential of the
lamp. As the voltage across C
R
decays to the preheat frequency.
During the Preheat Mode, the operating frequency
is determined by the parallel combination of R
R
frequency, along with the Preheat Time, is normally
chosen to ensure that adequate heating of the lamp
filaments occur. Typically, a 4.5:1 ratio of the hot
filament-to-cold filament resistance is desired for
maximum lamp life, as shown in Figure 7.
T
START
T
T
, combined with the value of C
4.0V
2.0V
and R
lead voltage, the output frequency exponentially
, and R
DT
, as shown in Figure 6. This frequency is
T
, combined with the values of C
R1
R2 Q
VOLTAGE
S
DETECT
UNDER-
Q
START
T
charges up to the
and R
www.irf.com
DT
PH
. This
START
and
PH
,
,