ISOLATED DC/DC CONVERTER, FEEDBACK CIRCUIT THEREOF, POWER SUPPLY DEVICE, POWER SUPPLY ADAPTOR, AND ELECTRONIC DEVICE USING THE SAME

摘要

A feedback circuit includes: an input terminal which receives a voltage detection signal corresponding to an output voltage of a DC/DC converter; an output terminal connected to an input side of the photo coupler; a ground terminal; a shunt regulator configured to amplify an error between the voltage detection signal and its target voltage and pull up a first current corresponding to the error from the input side of the photo coupler via the output terminal; and a protection circuit configured to pull up a second current from the input side of the photo coupler via the output terminal when an abnormality of the secondary side of the DC/DC converter is detected. The feedback circuit is packaged into a single module.

主权项

1. A feedback circuit disposed at a secondary side of an isolated DC/DC converter, wherein the DC/DC converter includes:
a transformer having a primary winding and a secondary winding; a switching transistor connected to the primary winding of the transformer; a rectification element connected to the secondary winding of the transformer; a photo coupler; a primary side controller which is connected to an output side of the photo coupler and is configured to switch the switching transistor in response to a feedback signal from the photo coupler; and the feedback circuit configured to drive the photo coupler, the feedback circuit comprising:
an input terminal which receives a voltage detection signal corresponding to an output voltage of the DC/DC converter;an output terminal connected to an input side of the photo coupler;a ground terminal;a shunt regulator configured to amplify an error between the voltage detection signal and its target voltage and draw a first current corresponding to the error from the input side of the photo coupler via the output terminal; anda protection circuit configured to draw a second current from the input side of the photo coupler via the output terminal when an abnormality of the secondary side of the DC/DC converter is detected, and wherein the feedback circuit is packaged in a single module.