Figure 2 shows an applications circuit with paralleled out-

put drivers. If it is required to drive high gate charge

MOSFETs, the UCC3776 output drivers can be combined

for higher peak current capability. It is good practice to pro-

vide separate gate resistor networks to each individual

MOSFET as shown. This will ensure that each driver cir-

cuit will not see excessive current during the high gate

charge portion of the switching waveform. This practice

also tends to isolate driver circuits to reduce the possibility

of ringing and crosstalk. If all four drivers are used to drive

a single MOSFET, then four separate gate drive resistor

networks should be used.

Figure 3 shows a transformer coupled full bridge power

stage. The UCC3776 is ideally suited for interfacing

between low power PWM outputs and high power output

stages. Although the UC3879 phase shift controller is

shown in this example, the UCC3776 can be used in

many PWM controller applications where high power FET

drivers are required.

6

UCC1776

UCC2776

UCC3776

Figure 2. Parallel Output Drivers

APPLICATION INFORMATION (cont.)

UDG-96007

Figure 3. Full Bridge Driver Application

UDG-96008-1

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