LMG3410 Datasheet, PDF (19/33 Pages) Texas Instruments – 600-V 12-A Single Channel GaN Power Stage

www.ti.com
Using a Bootstrap Diode (continued)
LMG3410
SNOSD10A – APRIL 2016 – REVISED JUNE 2016
VDD
DRAIN
VF
GND
SOURCE
+
±
VDD
DRAIN
VF
GND
SOURCE
Copyright © 2016, Texas Instruments Incorporated
Figure 14. Charging Path for Bootstrap Diode
The recommended bootstrap supply connection includes a bootstrap diode and a series resistor with an optional
zener as shown in Figure 15. The series resistor limits the charging current at startup and when the low-side
device is operating in third-quadrant mode. This resistor must be chosen to allow sufficient current to power the
LMG3410 at the desired operating frequency. At 100 kHz operation, a value of approximately 5.1 ohms is
recommended. At higher frequencies, this resistor value should be reduced or the resistor omitted entirely to
ensure sufficient supply current.
+12 V
VDD
DRAIN
VF
GND
SOURCE
Copyright © 2016, Texas Instruments Incorporated
Figure 15. Suggested Bootstrap Regulation Circuit
Using a series resistor with the bootstrap supply will create a charging time constant in conjunction with the
bypass capacitance on the order of a microsecond. When the dead time, or third-quadrant conduction time, is
much lower than this time constant, the bootstrap voltage will be well-controlled and the optional zener clamp in
Figure 15 will not be necessary. If a large deadtime is needed, a 14-V zener diode can be used in parallel with
the V_DD bypass capacitor to prevent damaging the high-side LMG3410.
Copyright © 2016, Texas Instruments Incorporated
Product Folder Links: LMG3410
Submit Documentation Feedback
19