| 摘要 |
PURPOSE:To reduce the power consumption of a series regulator by using the inter-electrode voltage of a series control element of the series regulator to control the switching operation of a switching element that controls the input of the switching regulator. CONSTITUTION:For instance, the output of a switching regulator increases due to the increase of the input voltage Vin. This rises up the inter-terminal voltage of a collector C2 and therefore increases the voltage between the collector and the emitter, i.e., the voltage between the collector and the base of a transistor TR2. In such a case, the base current of a TR3 is increased and therefore the collector current of the TR3 is also increased. This causes the increase of the drive current of the light emitting element of a photocoupler PC. Here the energy stored in a transformer T1 is decreased owing to the increase of the OFF period of a TR1. Then the electric power supplied to the capacitor C2 is reduced and the voltage supplied to the collector of the TR2 is reduced. Thus the collector-emitter voltage of the TR2 is reduced.
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