IRS21571DSPBF International Rectifier, IRS21571DSPBF Datasheet - Page 18

• Manufacturer Part Number: IRS21571DSPBF
• Description: IC BALLAST CTRL 600V 16-SOIC
• Manufacturer: International Rectifier
• Type: Ballast Controllerr

Specifications of IRS21571DSPBF

• Frequency: 43.7 ~ 48.3 kHz
• Current - Supply: 10mA
• Current - Output: 180mA
• Voltage - Supply: 11.5 V ~ 15.6 V
• Operating Temperature: -40°C ~ 125°C
• Package / Case: 16-SOIC (0.154", 3.90mm Width)
• Package: 16-lead SOIC Narrow
• Circuit: Fluorescent Ballast IC
• Offset Voltage (v): 600
• Output Source Current Min (ma): 180
• Output Sink Current Min (ma): 260
• Pbf: Yes
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

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The Preheat Time is programmed by means of the preheat capacitor, C
an internal threshold on the CPH pin of 4.0V, according to the following formula:
At the end of the Preheat Time, the internal, open-drain transistor holding the RPH pin to ground turns off, and
the voltage on this pin charges exponentially up to the R
output frequency exponentially decays to a minimum value. The rate of decay of this frequency is a function of
the R
reaches 5.15V, the Ignition Ramp Mode is always 1/4th as long as the preheat time.
When the CPH pin reaches 5.15V, an open-drain transistor on the RUN pin turns on, and the external R
resistor is then in parallel with the R
parallel combination of R
means of R
The following graphs, Figures 8 and 9, illustrate the relationship between the effective R
parallel combination of resistors which programs the C
PH
∗ C
RUN
RAMP
.
time constant. Because the Ignition Ramp Mode ends when the voltage on the CPH pin
RUN
and R
T
Figure 7: Lamp filament voltage during the
, and this means that the operating power of the lamp can be programmed by
T
preheat, ignition ramp and run modes
resistor. The Run Mode operating frequency is therefore a function of the
C
t
PH
PH
Preheat
=
= 250E - 9 t
4E6 C ,
T
18
capacitor charging current) and the operating frequency.
⋅
Ignition
Ramp
T
PH
pin potential. During this Ignition Ramp Mode, the
⋅
PH
Run
or
PH
, an internal 1μA current source, and
© 2008 International Rectifier
T
IRS21571D
resistance (i.e., the
RUN