ISL6551_15 Datasheet, PDF (23/27 Pages) Intersil Corporation – ZVS Full Bridge PWM Controller

ISL6551
Inverting Drivers- Inverting the SYNC signals or the LOWER
signals with external high current drivers to drive the
synchronous FETs.
Noninverting Drivers- Cascading SYNC signals with
noninverting high current drivers to drive the synchronous
FETs. There is a dead time between SYNC1 and SYNC2. For a
higher efficiency, Schottky diodes are normally in parallel with
the synchronous FETs to reduce the conduction losses during
the dead time in high output current applications.
Primary FET Drivers
Q3_G
LOWER1
LOWER2
Q3_S
Q4_S
Q4_G
Primary Control- This requires a pulse transformer, operating
at the switching frequency, for isolation. There are three
options to drive the synchronous FETs, as described in previous
lines.
LOWER1
LOWER2
HIP2100IB
HI HO
LI HS
VSS LO
Q3_G
Q3_S
Q4_G
Q4_S
FIGURE 27A. PUSH-PULL MEDIUM CURRENT DRIVERS
FIGURE 27B. PUSH-PULL HIGH CURRENT DRIVERS
LOWER1
LOWER2
HIP2100IB
HI ^HO
LI ^HS
VSS LO
Q3_G
Q3_S
Q4_G
PGND
Q4_S
FIGURE 27C. PUSH-PULL PRIMARY CONTROL
FIGURE 27. PUSH-PULL DRIVERS
Push-pull Medium CurrenPRIMARY CONTROLt Drivers- Upper
drivers are not used. No external drivers are required.
Secondary control. Operate at the switching frequency.
Push-pull High Current Drivers- Upper drivers are not used.
External high current drivers are required and less power is
dissipated in the ISL6551 controller. Secondary control.
Operate at the switching frequency.
Push-pull Primary Control- Upper drivers are not used. Both
lower drivers can directly drive the power switches. External
drivers are required in high gate capacitance applications.
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FN9066.6
April 30, 2015