| 摘要 |
For load currents greater than a threshold current, the voltage regulator operates in a conventional manner by fully turning on and off one or more switching transistors (16) at a duty cycle necessary to maintain the output voltage a regulated voltage. Upo n a load current below a threshold being detected (76), a controller stops the switching of t he transistor(s) and applies a reduced drive signal (44) to the high side transistor so as to app ly a constant trickle current to the load. Unnecessary components are shut down to save power (42) . When the output voltage falls below a threshold (46), the normal switching routine is resumed to recharge the regulator's output capacitor (28) to a certain level, and the regulator once again enters the light load current mode. By not completely shutting down the transistors at light load currents, as in done in a conventional intermittent-operation mode, the re is lower power loss by less frequent switching of the transistor(s).
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