Patent ID: 9385604
Filing Date: 2016-07-05
CPC Classification: H02M

Claim Text:
1. A DC/DC converter for a switching power supply device including a plurality of DC/DC converters which include a master DC/DC converter and a plurality of slave DC/DC converters and have output terminals connected in parallel to each other, comprising: first and second terminals that are used to cascade the plurality of DC/DC converters in a line; a control circuit that determines that a host DC/DC converter is the master DC/DC converter when a predetermined voltage is detected at the second terminal and determines that the host DC/DC converter is the slave DC/DC converter when the predetermined voltage is not detected, and controls a current output from the second terminal based on whether the host DC/DC converter is the master DC/DC converter or the slave DC/DC converter. wherein the first terminal of the slave DC/DC converter which is far from the master DC/DC converter is grounded, (1) when the host DC/DC converter is determined to be the slave DC/DC converter, the control circuit detects a current value of a current which flows from the first terminal; and adds a predetermined addition current value to the detected current value and outputs a current with the sum of the current values through the second terminal if the host DC/DC converter is operating, or outputs the current with the detected current value through the second terminal if the host DC/DC converter does not operate, and (2) when the host DC/DC converter is determined to be the master DC/DC converter, the control circuit divides the detected current value by the addition current value, detects the number of converters which are operating based on the divided value, and transmits information indicating the detected number of operating converters to the slave DC/DC converter.