| 摘要 |
An apparatus for establishing an operating parameter for a power supply device having an output includes: (a) a first signal source; (b) a second signal source; (c) a third signal source; and (d) a state device. The first signal source is controllable for generating a programming signal. The second signal source generates a load indicating signal and is connected with the power supply. The third signal source generates an offset signal. The state device has a first input and a second input and changes state when the first input has a predetermined relationship with the second input. The first input is determined by relative values of the programming signal and the offset signal. The second input is related with the output. The power supply device shuts down when the state device changes state. The method includes the steps of: (a) providing, in no particular order, the following signals: (1) a programming signal appropriate for the shutdown circumstance; and (2) an offset signal; (b) applying a signal representative of the output to a first input of a state device; (c) substantially simultaneously with step (b), applying one of the following signals to a second input of the state device: (1) the programming signal; or (2) a combination of the programming signal and the offset signal; and (d) changing state of the state device when the first input has a predetermined relationship with the second input. The shutdown circumstance is effected when the state changes.
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