IR21571 International Rectifier, IR21571 Datasheet - Page 11
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IR21571
Manufacturer Part Number
IR21571
Description
IC BALLAST CONTROL 16-DIP
Manufacturer
International Rectifier
Type
Ballast Controllerr
Datasheet
1.IR21571PBF.pdf
(18 pages)
Specifications of IR21571
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-DIP (0.300", 7.62mm)
Lead Free Status / RoHS Status
Contains lead / RoHS non-compliant
Other names
*IR21571
Available stocks
Company
Part Number
Manufacturer
Quantity
Price
Part Number:
IR21571
Manufacturer:
IR
Quantity:
20 000
Part Number:
IR21571S
Manufacturer:
IR
Quantity:
20 000
Company:
Part Number:
IR21571STR
Manufacturer:
IR
Quantity:
191
Part Number:
IR21571STRPBF
Manufacturer:
IR
Quantity:
20 000
The Preheat Time is programmed by means of the
preheat capacitor, C
source, and an internal threshold on the C
4.0V, according to the following formula:
At the end of the Preheat Time, the internal, open-
drain transistor holding the R
off, and the voltage on this lead charges exponentially
up to the R
Mode, the output frequency exponentially decays to
a minimum value. The rate of decay of this frequency
is a function of the R
the Ignition Ramp Mode ends when the voltage on
the C
is always 1/4th as long as the preheat time.
When the C
transistor on the RUN lead turns on, and the external
R
The Run Mode operating frequency is therefore a
function of the parallel combination of R
and this means that the operating power of the lamp
can be programmed by means of R
www.irf.com
RUN
PH
resistor is then in parallel with the R
Figure 7: Lamp filament voltage during the
lead reaches 5.15V, the Ignition Ramp Mode
preheat, ignition ramp and run modes.
T
lead potential. During this Ignition Ramp
PH
C
t
PH
PH
lead reaches 5.15V, an open-drain
=
Preheat
4.7E6
213E
PH
PH
* C
, an internal 1 A current
9 -
PH
C
Ignition
PH
Ramp
time constant. Because
PH
t
PH
,
lead to ground turns
or
RUN
Run
.
RUN
PH
T
resistor.
and R
lead of
T
,
The following graphs, Figures 8 and 9, illustrate the
relationship between the effective R
the parallel combination of resistors which programs
the C
frequency.
FREQ
(KHz)
FREQ
(KHz)
Figure 8: fosc versus effective R
Figure 9: fosc versus effective R
150
100
50
0
0
250
200
150
100
T
50
0
capacitor charging current) and the operating
0
5
5
IR21571 (S) & (PbF)
10
10
15
15
RT (K ohms)
RT (K ohms)
20
20
25
T
T
25
(t
(t
CT=220pF, RDT=5.6K
CT=470pF, RDT=2.7K
CT=1nF, RDT=1.2K
CT=220pF,RDT=11K
CT=470pF,RDT=6.2K
CT=1nF,RDT=3K
DEAD
DEAD
T
30
resistance (i.e.,
30
= 2.0 usec)
= 1.0 usec)
35
35
40
40
11