| 摘要 |
A power supply (10) for a satellite receiver system includes a dual input supply voltage arrangement (200). When a higher output v oltage is selected, a source of a lower supply input voltage is coupled to an input, main current conducting terminal of a series pass transistor (Q1). On the other hand, when a lower output voltage is selected, a source of a lower supply input voltage is coupled to the input main current conducting terminal of the series pass transistor. A comparator (22) senses a magnitude of an output voltage (16) produced by the series pass transistor. When, as a result of an over current condition, the output voltage is lower than a reference threshold level (22a), any selection of the higher output voltage is automatically over-ridden and the source of the lower supply input voltage, instead, is coupled to the input main current conducting terminal of the series pass transistor.
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