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3
ISL6752
VIN+
+ C1
400 VDC
CR2
Q8A R10 Q8B Q1
C8
R1
VIN-
Q6A Q4 Q6B
T3
CR3
R11 Q5A Q2
Q5B C9
Q10A C10
Q9A
Q10B
Q9B
Q7A Q3 Q7B
T1
R13 C13
T2 CR1
R2 R3
Q11
VDD C2
VR1
R19 R8
R20
R7 R4
R1
VREF R7
R8 R9
R6
VADJ VREF
VDD OUTLL
ISL6752
VERR OUTLR
CTBUF OUTUL
RTD
OUTUR
RESDEL OUTLLN
CT
OUTLRN
CS
GND
U1
SECONDARY BIAS
SUPPLY
C2
R4
R5
C6
R2 R3
C3 C4 C5
T1 Np:Ns:Ns = 9:2:2
®
Data Sheet
October 31, 2008
ISL6752
FN9181.3
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.
4
ISL6752
VIN+
Q1 Q5 R13 CR2
T3 1:1:1
Q2 Q6 CR3 R12
400 VDC
+ C1
Q4 Q7A R10
Q7B
CR4 C8
Q10A
C10
Q10B
T4 1:1:1
Q9A Q9B
CR5
Q3 Q8A R11 Q8B C9
Q11A
C7
Q12A
Q11B
Q12B
VIN-
T2 CR1
Thermal Information
Thermal Resistance Junction to Ambient (Typical)
Operating Conditions
Temperature Range . . . . . . . . . . . . . . . . . . . . . . . . .-40°C to +105°C Supply Voltage Range (Typical). . . . . . . . . . . . . . . . 9VDC to 16VDC
Ns
Np
Ns
Q16
R14 Q15
C11
R15 L1
C12
C13 C14 +
Q13A Q13B
Q14A Q14B
R17
C16
C17
Q17
C15 R18
R16
R20
VREF R22
U3 +
R19 R21
C18
+ VOUT RETURN
FN9181.3
October 31, 2008
ISL6752
Absolute Maximum Ratings (Note 2)
ISL6752 (16 LD QSOP) VREF 2 VERR 3 CTBUF 4
RTD 5 RESDEL 6
CT 7 CS 8
16 VDD 15 OUTLL 14 OUTLR 13 OUTUL 12 OUTUR 11 OUTLLN 10 OUTLRN 9 GND
1
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
Features
• Adjustable Resonant Delay for ZVS Operation • Synchronous Rectifier Control Outputs with Adjustable
Delay/Advance • 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)
R5 R6
C3 C17 C4 R21
VADJ
VDD
VREF OUTLL
ISL6752
VERR OUTLR
CTBUF OUTUL
RTD
OUTUR
RESDEL OUTLLN
CT
OUTLRN
CS
GND
U1
R23
R24
R22
C16
EL7212 C5 T4
U5
R23 CR4
Q14 C6
R24 U2
Q12 Q13
Supply Voltage, VDD . . . . . . . . . . . . . . . . . . . GND - 0.3V to +20.0V OUTxxx . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . GND - 0.3V to VDD Signal Pins . . . . . . . . . . . . . . . . . . . . . . . GND - 0.3V to VREF + 0.3V VREF . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . GND - 0.3V to 6.0V Peak GATE Current . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.1A
70ns LEADING
EDGE BLANKING
+
-
PWM COMPARATOR
80mV 0.33
VREF 1mA
CS VERR
ISL6752
Typical Application - High Voltage Input Primary Side Control ZVS Full-Bridge Converter
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.
EL7212 U4
R12 C12
L1 C15
C7 +
+ VOUT
RETURN
R18 R17
R16
C14
C11 R15
U3 R14
FN9181.3
October 31, 2008
Typical Application - High Voltage Input Secondary Side Control ZVS Full-Bridge Converter