Patent ID: 7586299

Claim:
A power-supply semiconductor integrated circuit for realizing a parameter-deciding power-supply circuit, which, in order to decide a parameter of a power-supply circuit that supplies power to a load device, is connected to the load device in place of the power-supply circuit, wherein the power-supply circuit and the parameter-deciding power-supply circuit are switching power-supply circuits, and the power-supply semiconductor integrated circuit further comprises: one or more transistor arrays, each including a plurality of transistors operable as switching transistors of the parameter-deciding power-supply circuit; and a selecting circuit operable as a control circuit to select a transistor to be operated as a switching transistor from among the plurality of transistors, so as to control a size of the transistor that operates as a switching transistor, wherein the selecting circuit varies the size of the transistor as a parameter of the power-supply circuit, according to an external command.