| 摘要 |
A power control system includes a current sense resistor located on an output side of a switching power converter. By locating the current sense resistor on the output side of the switching power converter, the current sense resistor conducts a sense current when a control switch of the switching power converter is nonconductive. Since a duty cycle of the control switch is larger for a low input voltage than for a higher input voltage, the current sense resistor conducts current for a shorter time duration for low input voltages than for higher input voltages. Thus, the root mean square (RMS) of a sense current in the current sense resistor and, thus, power dissipation by the current sense resistor, is lower during low input voltages than power dissipation in conventionally located current sense resistors. The RMS of the sense current is approximately constant across a full range of input voltages.
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