FN9181 Rev 4.00

Page 1 of 18

August 1, 2016

FN9181

Rev 4.00

August 1, 2016

ISL6752

ZVS Full-Bridge Current-Mode PWM with Adjustable Synchronous Rectifier

Control

DATASHEET

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 dead time

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.

Related Literature

• AN1262, “Designing with the ISL6752, ISL6753 ZVS

Full-Bridge Controllers”

• AN1603, “ISL6752/54EVAL1Z ZVS DC/DC Power Supply

with Synchronous Rectifiers User Guide”

• AN1619, “Designing with ISL6752DBEVAL1Z and

ISL6754DBEVAL1Z Control Cards”

Features

• Adjustable resonant delay for ZVS operation

• Synchronous rectifier control outputs with adjustable

delay/advance

•Current-mode control

• 3% current limit threshold

• Adjustable dead time 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)

Applications

• ZVS full-bridge converters

• Telecom and datacom power

• Wireless base station power

• File server power

• Industrial power systems

Pin Configuration

ISL6752

(16 LD QSOP)

TOP VIEW

14

15

16

9

13

12

11

10

1

2

3

4

5

7

6

8

VADJ

VREF

VERR

CTBUF

RTD

RESDEL

CS

CT

VDD

OUTLR

OUTUL

OUTUR

OUTLLN

OUTLRN

GND

OUTLL