IRS2158DSTRPBF International Rectifier, IRS2158DSTRPBF Datasheet - Page 19

• 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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When LO and HO are both oscillating, the external MOSFETs (MHS and MLS) are turned on and off with a
50% duty cycle and a non-overlapping deadtime of 1.5 μs. The half-bridge output (pin VS) begins to switch
between the DC bus voltage and COM. During the deadtime between the turn-off of LO and the turn-on of
HO, the half-bridge output voltage transitions from COM to the DC bus voltage at a dv/dt rate determined by
the snubber capacitor (C
diode (D
internal 15.6 V zener clamp of the IC take over as the supply voltage. Capacitor C
current during the VCC discharge time and should be large enough such that VCC does not decrease below
VCCUV- before the charge pump takes over. Capacitor C
placed as close as possible and directly between VCC and COM, and should not be lower than 0.1uF.
Additional resistors are recommended for limiting high currents that can flow to VCC from the charge pump
during hard-switching of the half-bridge or during lamp ignition. In the application circuit shown above, DCP2
is a 17 V zener diode, which serves to limit the voltage transients that are supplied to VCC through the
charge pump, under these conditions. The IC may not operate correctly if steps are not taken to prevent
overdriving VCC through the charge pump.
The internal bootstrap MOSFET and supply capacitor (C
driver circuitry. During UVLO mode, the high- and low-side driver outputs HO and LO are both low, the
internal oscillator is disabled, and pin CPH is connected internally to COM for resetting the preheat time.
Preheat Mode (PH)
The IRS2158D enters preheat mode when VCC exceeds the UVLO positive-going threshold (VCCUV+) and
the VDC pin voltage is above the 5 V threshold. The internal MOSFET that connects pin CPH to COM is
turned off and an external resistor (Figure 3) begins to charge the external preheat timing capacitor (CPH).
LO and HO begin to oscillate at a higher soft-start frequency and ramp down quickly to the preheat
frequency. The VCO pin is connected to COM through an internal
CP2
) to VCC. After several switching cycles of the half-bridge output, the charge pump and the
SNUB
). As the snubber capacitor charges, current will flow through the charge pump
V
C1
Figure 2: VCC supply voltage.
R
TIME
CONSTANT
V
V
VCC
UVLO+
UVLO-
& C
VHYST
VCC1,2
DISCHARGE
C
VCC
19
CHARGE PUMP
OUTPUT
BS
DISCHARGE
TIME
) comprise the supply voltage for the high side
VCC1
INTERNAL VCC
ZENER CLAMP VOLTAGE
is required for noise filtering and must be
t
© 2009 International Rectifier
IRS2158D(S)
VCC2
supplies the IC