| 摘要 |
<p>In an improved inverter, an AC electrical output is produced in the secondary windings of a transformer by alternately switching direct current in a primary winding using active switch elements. The alternate switching action of the active switch elements is controlled by stored energy variations in a tertiary winding of the transformer and by a high efficiency switching control circuit. The control circuit includes a current-sensitive latch circuit which is triggered to its conductive state to initiate a switching transition of the active switch elements when a predetermined level of primary winding current is detected. Also, the current-sensitive latch circuit is used to terminate normal inverter operation in response to excessive inverter load current or in response to excessive operating temperature. A special thermal protection circuit is employed to monitor operating temperature and trigger the current-sensitive latch circuit when the temperature is excessive. The thermal protection circuit is especially adapted to protect integrated circuits, and is itself formed within an integrated circuit in a preferred embodiment. A restarting circuit uses another current-sensitive latch circuit to provide periodic starting pulses in the absence of normal inverter operation and to supplement control circuit and switching circuit supply currants during normal inverter operation.</p> |
