October 31, 2008
ZVS Full-Bridge Current-Mode PWM with
Adjustable Synchronous Rectifier Control
The ISL6752 is a high-performance, low-pin-count alternative
zero-voltage switching (ZVS) full-bridge PWM controller. Like
Intersil’s ISL6551, it achieves ZVS operation by driving the
upper bridge FETs at a fixed 50% duty cycle while the lower
bridge FETs are trailing-edge modulated with adjustable
resonant switching delays. Compared to the more familiar
phase-shifted control method, this algorithm offers equivalent
efficiency and improved overcurrent and light-load performance
with less complexity in a lower pin count package.
The ISL6752 features complemented PWM outputs for
synchronous rectifier (SR) control. The complemented
outputs may be dynamically advanced or delayed relative to
the PWM outputs using an external control voltage.
This advanced BiCMOS design features precision deadtime
and resonant delay control, and an oscillator adjustable to
2MHz operating frequency. Additionally, Multi-Pulse
Suppression ensures alternating output pulses at low duty
cycles where pulse skipping may occur.
(Pb-free) DWG. #
ISL6752AAZA* ISL 6752AAZ -40 to +105 16 Ld QSOP M16.15A
*Add “-T” suffix for tape and reel. Please refer to TB347 for details on
NOTE: These Intersil Pb-free plastic packaged products employ
special Pb-free material sets, molding compounds/die attach
materials, and 100% matte tin plate plus anneal (e3 termination
finish, which is RoHS compliant and compatible with both SnPb and
Pb-free soldering operations). Intersil Pb-free products are MSL
classified at Pb-free peak reflow temperatures that meet or exceed
the Pb-free requirements of IPC/JEDEC J STD-020.
• Adjustable Resonant Delay for ZVS Operation
• Synchronous Rectifier Control Outputs with Adjustable
• Current-Mode Control
• 3% Current Limit Threshold
• Adjustable Deadtime Control
• 175µA Start-up Current
• Supply UVLO
• Adjustable Oscillator Frequency Up to 2MHz
• Internal Over-Temperature Protection
• Buffered Oscillator Sawtooth Output
• Fast Current Sense to Output Delay
• Adjustable Cycle-by-Cycle Peak Current Limit
• 70ns Leading Edge Blanking
• Multi-Pulse Suppression
• Pb-Free (RoHS Compliant)
• ZVS Full-Bridge Converters
• Telecom and Datacom Power
• Wireless Base Station Power
• File Server Power
• Industrial Power Systems
(16 LD QSOP)
1 CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
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