Power Factor Correction Controllers
The ISL6731A and ISL6731B are active power factor
correction (PFC) controller ICs that use a boost topology. The
controllers are suitable for AC/DC power systems up to 2kW
and over the universal line input.
The ISL6731A and ISL6731B operate in Continuous Current
Mode (CCM). Accurate input current shaping is achieved with a
current error amplifier. A patent pending breakthrough
negative capacitance technology minimizes zero crossing
distortion and reduces the magnetic components size. The
small external components result in lower design cost without
The internally clamped 12.5V gate driver delivers 1.5A peak
current to the external power MOSFET. The ISL6731A and
ISL6731B provide a highly reliable system that is fully
protected. Protection features include cycle-by-cycle
overcurrent, over power limit, over-temperature, input
brownout, output overvoltage and undervoltage protection.
The ISL6731A and ISL6731B provide excellent power
efficiency and transitions into a power saving skip mode
during light load conditions, thus improving efficiency
automatically. The ISL6731A and ISL6731B can be shut down
by pulling the FB pin below 0.5V or grounding the BO pin.
Two switching frequency options are provided. The ISL6731B
switches at 62kHz, and the ISL6731A switches at 124kHz.
• AN1884, "ISL6731AEVAL1Z and ISL6731BEVAL1Z: Boost
CCM PFC for 300W Universal Input Adaptors"
• AN1885, “ISL6731AEVAL2Z and ISL6731BEVAL2Z: High
Performance Boost CCM PFC Front End for Server Power
• Reduced component size requirements
- Enables smaller, thinner AC/DC adapters
- Choke and cap size can be reduced
- Lower cost of materials
• Excellent power factor and THD over line and load
- CCM mode with negative capacitance generator for
smaller EMI filter and improved performance
- Built-in current amplifier with flexibility of gain change
• Better light-load efficiency
- Automatic pulse skipping with programmable threshold
- Programmable or automatic shutdown
• Highly reliable design
- Cycle-by-cycle current limit
- Input average power limit
- OVP and OTP protection
- Input brownout protection
• Small 14 Ld SOIC package
• Desktop computer AC/DC adaptor
• Laptop computer AC/DC adaptor
• TV AC/DC power supply
• AC/DC brick converters
VIN ISL6731A FB
BO SKIP VREG
FIGURE 1. TYPICAL APPLICATION
20 40 60
OUTPUT POWER (%)
FIGURE 2. PFC EFFICIENCY
February 13, 2015
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
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