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

摘要

An isolated 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 feedback amplifier connected to an input side of the photo coupler and configured to generate an error current which increases as an output voltage of the DC/DC converter decreases; a primary side controller having a feedback terminal and configured to switch the switching transistor with a larger duty ratio as a voltage of the feedback terminal becomes higher; and a non-inversion type feedback circuit connected to the output side of the photo coupler and the feedback terminal and configured to increase the voltage of the feedback terminal as a feedback current flowing through the output side of the photo coupler increases.

主权项

1. An isolated DC/DC converter comprising:
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 feedback amplifier connected to an input side of the photo coupler and configured to generate an error current which increases as an output voltage of the DC/DC converter decreases; a primary side controller having a feedback terminal and configured to switch the switching transistor with a larger duty ratio as a voltage of the feedback terminal becomes higher; and an non-inversion type feedback circuit connected to an output side of the photo coupler and the feedback terminal and configured to increase the voltage of the feedback terminal as a feedback current flowing through the output side of the photo coupler increases.