Texas Instruments LM74610-SQEVM, Руководство пользователя

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Operation
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3.2 Output Voltage
When power is initially applied, the load current (I
D
) will flow through the body diode of the MOSFET. This
current will produce a forward voltage drop (V
f
) across the MOSFET body diode. This voltage is used to
charge up the charge pump capacitor Vcap. This periodic voltage drop will be equal to the MOSFET body
diode forward voltage drop and occurs for about 25.6msec as shown in
Figure 5 .
Figure 5. Periodic body diode voltage drop at the output
During the rest of the period of conduction, the LM74610-Q1 will drive the gate of the MOSFET. When the
MOSFET is ON, it provides a low resistive path for the drain current to flow and minimizes the power
dissipation associated with forward conduction. The power losses during the MOSFET ON state depend
primarily on the R
DSON
of the selected MOSFET and load current. The LM74610-Q1 operation keeps the
MOSFET ON at approximately 98% as shown in Figure 6 , leading to very little overall power dissipation
when compared to a typical diode.
8 List of Tables SNVU489 – October 2015
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