IRS21571DSPBF International Rectifier, IRS21571DSPBF Datasheet - Page 15

• 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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These connection techniques prevent high current ground loops from interfering with sensitive timing component
operation, and allows the entire control circuit to reject common-mode noise due to output switching.
The Control Sequence and Timing Component Selection
The IRS21571D uses the following control sequence (Figure 3) to drive rapid start fluorescent lamps.
The control sequence used in the IRS21571D allows the Run Mode operating frequency of the ballast to be
higher than the ignition frequency (i.e., f
types where the ignition frequency is too close to the run frequency to ensure proper lamp striking for all
production resonant LC component tolerances (please note that it is possible to use the IRS21571D in systems
where f
Six pins in the IC are used to control the Startup, Preheat, Ignition Ramp, and Run modes of operation, and to
allow ballast and lamp engineers the flexibility to optimize their designs for virtually any lamp type.
The heart of this controller is an oscillator which resembles those found in many popular PWM voltage regulator
ICs. In its simplest form, this oscillator consists of a timing resistor and capacitor connected to ground. The
voltage across the timing capacitor C
current in the R
oscillograph in Figure 4 illustrates the relationship between the oscillator capacitor waveform and the gate driver
outputs.
start
> f
ph
T
> f
pin, and the falling portion of the ramp is determined by an external deadtime resistor R
ign
> f
run
, simply by leaving the RUN pin open).
Figure 3: IRS21571D Control sequence
T
V
V
V
is a sawtooth, where the rising portion of the ramp is determined by the
f
f
f
f
Start
PH
Run
min
CPH
RPH
RUN
start
5V
2V
2V
> f
ph
Preheat mode
> f
run
15
> f
ign
). This control sequence is recommended for lamp
Ignition
Ramp
mode
Run mode
t
© 2008 International Rectifier
IRS21571D
DT
. The