IRS2158DSTRPBF International Rectifier, IRS2158DSTRPBF Datasheet - Page 21

• Manufacturer Part Number: IRS2158DSTRPBF
• Description: IC BALLAST CTRL 600V 16-SOIC
• Manufacturer: International Rectifier
• Type: Fluorescent Lamp Driverr

Specifications of IRS2158DSTRPBF

• Frequency: 42.5 ~ 48.5 kHz
• Current - Supply: 3.5mA
• Current - Output: 260mA
• Voltage - Supply: 11.5 V ~ 15.6 V
• Operating Temperature: -40°C ~ 125°C
• Package / Case: 16-SOIC (3.9mm Width)
• For Use With: IRPLDIM3 - KIT DES FLUOR BALLAST IRS2158D
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

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The over-current threshold on pin CS (VCSTH+) will protect the ballast against a non-strike or open-filament
lamp fault condition. The voltage on pin CS is defined by the lower half-bridge MOSFET current flowing
through the external current sensing resistor RCS. This resistor programs the maximum peak ignition current
(and therefore peak ignition voltage) of the ballast output stage. Should this voltage exceed the internal
VCSTH+ threshold of 1.2 V, the ignition regulation circuit discharges the VCO voltage slightly to increase the
frequency slightly (see Figure 6). This cycle-by-cycle feedback from the CS pin to the VCO pin will adjust
the frequency each cycle to limit the amplitude of the current for the entire duration of ignition mode.
The IRS2158D remains in IGNITION mode until the voltage at CPH reaches 1/2*VCC at which point it will
switch into PRE-RUN mode.
Pre-Run Mode
In PRE-RUN mode the fault counter is disables so that the IRS2158D will enter FAULT mode if a single
event occurs where VCS>1.2 V (VCSTH+). This allows the ballast to shut down if the resonant inductor
saturates during ignition.
Figure 6: Ignition regulation timing diagram.
V
1.2V
V
HO
LO
VS
V
V
VCO
CS
BUS
BUS
5V
(+)
(-)
R
C
C
R
R
Figure 5: Ignition circuitry.
CPH
PH
VCO
FMIN
PH
VCC
FMIN
CPH
VCO
3
4
5
IRS2158D
1.2K
MODE
M2
M1
21
OSC.
12
CO
M
Bridge
Driver
Half-
+
-
1.2V
16
15
11
10
HO
VS
LO
CS
C
R
CS
3
R
MHS
MLS
Bridge
Output
CS
Half-
Load
Return
I
LOA
D
t
t
t
© 2009 International Rectifier
IRS2158D(S)