IRS27951SPBF International Rectifier, IRS27951SPBF Datasheet - Page 13

• Manufacturer Part Number: IRS27951SPBF
• Description: IC DRIVER HALF-BRIDGE 8SOIC
• Manufacturer: International Rectifier

Specifications of IRS27951SPBF

• Output Isolation: Isolated
• Frequency Range: 46.6kHz ~ 285kHz
• Voltage - Input: 12 V ~ 18 V
• Voltage - Output: 12 V ~ 18 V
• Power (watts): 833mW
• Package / Case: 8-SOIC (0.154", 3.90mm Width)
• Package: 8-lead SOIC
• Circuit: Resonant Half-Bridge
• Offset Voltage (v): 600
• Output Source Current Min (ma): 300
• Output Sink Current Min (ma): 900
• Vcc Range (v): 10-20V with UVLO
• Programmable Frequency (khz): 25-500
• Programmable Deadtime (ns): 200-2000
• Ocp Threshold (v): 2
• Pbf: Yes
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Application Information and Additional Details
Information regarding the following topics is included as subsections within this section of the datasheet.
General Description
The IRS2795 is a double-ended controller for the resonant half-bridge topology. It provides complementary outputs
with 50% (max) duty cycle; the high-side and low-side bridge devices are driven 180° out-of-phase for exactly the
same time. A programmable dead-time inserted between the turn-OFF of one switch and the turn-ON of the other
one guarantees soft-switching operation. The IC incorporates a multi-function oscillator that allows the designer to
program all the necessary features to control a half bridge resonant switch-mode power supply featuring low standby
power. The IC also incorporates additional protection features for robust operation and provides a high performance
solution while minimizing external components, design time, and printed circuit board real estate, all in an 8 pin SOIC
package.
The IC enables the designer to externally program all the following features using a 2 pin RC oscillator – operating
frequency range (start-up, minimum and maximum frequency), dead time, soft-start time and sleep mode operation.
IRS2795 also uses IR’s proprietary high-voltage technology to implement a VS sensing circuitry that monitors the
current through the low-side half bridge MOSFET for short circuit faults. By using the R
the IRS2795 eliminates the need for an additional current sensing resistor, filter and current-sensing pin. This
protection feature is latched and the thresholds are fixed at 2V for IRS27951 and 3V for IRS27952.
Finally, the controller IC also features a micro power startup current (ICC<100µA) and a user initiated sleep mode
during which the IC power consumption is less than 200µA (@ Vcc=15V). The sleep mode function allows system
designs with reduced standby power consumption and can be used to meet stringent energy standards from Blue
Angel, Energy Star etc.
IC Supply Circuit & Low start-up current
The UVLO circuit maintains the IC in UVLO mode if the VCC pin voltage is less than the VCC turn-on threshold,
VCCON. If the VCC pin voltage drops below the UVLO threshold VCCUVLO at anytime after start-up, the IC is
pushed back into UVLO mode. The current consumption in this mode is less than 100uA.
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General Description
IC Supply Circuit & Low start-up current
Multi-function 2 Pin Oscillator
Frequency and Dead-time Calculation
User initiated Micropower Sleep mode
Gate Drive Capability
System Protection Features
PCB Layout Tips
Additional Documentation
Figure 1: VCC Under Voltage Lockout
13
DSON
© 2010 International Rectifier
of the low-side MOSFET,
IRS27951S
IRS27952S