| 摘要 |
The invention relates to a switched-mode power (300) supply comprising: a transformer (302) with a primary winding (306, 308) and a secondary winding (310), the secondary winding (310) having a first terminal and a second terminal; a rectifier (330) with an input and an output, the input coupled to the first terminal of the secondary winding (310); an output capacitor (332) with a first plate and a second plate, the first plate coupled to the output of the rectifier (330) and the second plate coupled to the second terminal of the secondary winding (310); a power switch coupled in series with the primary winding (306), configured to be coupled between an output of a rectifier (322) and ground; a signalling unit (338) provided in parallel with the secondary winding (310), the signalling unit (310) comprising a signalling capacitor (340) and a signalling switch (342) coupled in series with each other; a secondary controller (336) configured to: detect a secondary side variable at the secondary winding (310), and control the signalling switch (342) in accordance with the secondary variable, wherein closing the signalling switch (342) generates a transformer signal by connecting the signalling capacitor (340) to the secondary winding (310); a primary controller (304) configured to: receive the transformer signal from the primary winding (306) or a primary side auxiliary winding (308) of the transformer (302), and control the power switch in accordance with the transformer signal. |
