| CPC H02M 3/158 (2013.01) [H02M 1/08 (2013.01); H02M 1/44 (2013.01)] | 9 Claims |
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1. A power supply semiconductor device, comprising:
a first external terminal configured to be connected to a positive electrode of an input capacitor via a first external current path;
a second external terminal configured to be connected to a negative electrode of the input capacitor via a second external current path;
a third external terminal configured to be connected to the positive electrode of the input capacitor via a third external current path;
a fourth external terminal configured to be connected to the negative electrode of the input capacitor via a fourth external current path;
a first transistor and a second transistor provided between the first external terminal and the second external terminal and connected in series to each other;
a third transistor and a fourth transistor provided between the third external terminal and the fourth external terminal and connected in series to each other;
a switch terminal commonly connected to a connection node between the first transistor and the second transistor and a connection node between the third transistor and the fourth transistor; and
a drive control circuit configured to perform a switching control to alternately turn on and off a set of the first transistor and the third transistor and a set of the second transistor and the fourth transistor, thereby generating a switching voltage at the switch terminal based on a voltage across the input capacitor,
wherein an output voltage is obtained by rectifying and smoothing the switching voltage,
wherein each of the first, second, third, and fourth transistors includes a first electrode, a second electrode, and a control electrode,
wherein the drive control circuit is further configured to control an on/off state of each of the first, second, third, and fourth transistors by controlling a potential of the control electrode of each of the first, second, third, and fourth transistors based on a feedback voltage corresponding to the output voltage,
wherein the second electrode of each of the first transistor and the third transistor and the first electrode of each of the second transistor and the fourth transistor are commonly connected to the switch terminal,
wherein the power supply semiconductor device further comprises:
a first internal current path configured to connect the first external terminal and the first electrode of the first transistor;
a second internal current path configured to connect the second electrode of the first transistor and the first electrode of the second transistor;
a third internal current path configured to connect the second electrode of the second transistor and the second external terminal;
a fourth internal current path configured to connect the third external terminal and the first electrode of the third transistor;
a fifth internal current path configured to connect the second electrode of the third transistor and the first electrode of the fourth transistor; and
a sixth internal current path configured to connect the second electrode of the fourth transistor and the fourth external terminal,
wherein a first internal impedance sum and a second internal impedance sum for a predetermined frequency or direct current are different from each other,
wherein the first internal impedance sum is a sum of impedances of the first, second, and third internal current paths and on-resistances of the first transistor and the second transistor, and
wherein the second internal impedance sum is a sum of impedances of the fourth, fifth, and sixth internal current paths and on-resistances of the third transistor and the fourth transistor.
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