SM74101 Datasheet, PDF (12/23 Pages) Texas Instruments – SM74101 Tiny 7A MOSFET Gate Driver

SM74101
SNOSBA2B – JULY 2011 – REVISED MAY 2015
8 Application and Implementation
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NOTE
Information in the following applications sections is not part of the TI component
specification, and TI does not warrant its accuracy or completeness. TI’s customers are
responsible for determining suitability of components for their purposes. Customers should
validate and test their design implementation to confirm system functionality.
8.1 Application Information
The SM74101 can be used to drive a low side MOSFET with very low switching losses. Either one of the control
input pins, IN or INB, can be used to control the gate drive to the MOSFET. The choice of the control input pin
used will depend on the polarity of operation.
8.2 Typical Application
The SM74101 is utilized in a DC/DC forward topology power supply as shown in Figure 14. The high peak gate
drive current of the SM74101 allows for short rise and fall times on the primary side MOSFET, thereby improving
overall efficiency of the system and reducing switching losses. It is used in conjunction with the LM5025 Active
Clamp Voltage Mode PWM Controller to provide drive capability to the primary side MOSFET after isolation.
V_IN
V_OUT
+10V
V_CC
OUT
UVLO
IN_REF
V_EE
SM74101
IN
IN_REF
INB
+5V
V_CC
LM5110-1
OUT_B
IN_REF
V_EE
OUT_A
V_EE
INB
IN_REF
LM5025
CONTROLLER
OUT_B
FB
IN_A
OUT_A
-3V
Dual Supply
utilizing negative
Output voltage
Drive
Figure 14. DC/DC Forward Topology Power Supply
8.2.1 Design Requirements
The SM74101 is used in the non-inverting mode of operation. The IN pin is used to control the OUT signal to the
primary side MOSFET. The signal that travels from OUT_A and through the isolation transformer should be
compatible with the high and low threshold voltages of the IN pin. INB is not used in this mode and is therefore
connected to IN_REF, which is also the primary side ground.
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