Power supply substrate including transformer and snubber circuit

A power supply substrate for transforming an input voltage on a primary side and outputting an output voltage from a secondary side, the power supply substrate comprising:

• a transformer including a primary winding and a secondary winding;
• a switching element connected to the primary winding and configured to perform a switching operation;
• a rectifying smoothing circuit configured to rectify and smooth an output voltage outputted from the secondary winding and include a smoothing capacitor;
• and
• a control circuit configured to detect the output voltage and perform feedback control,
• wherein the transformer includes a first terminal and a second terminal for outputting a voltage from the secondary winding, and the transformer is mounted on a first surface of the power supply substrate,
• wherein the power supply substrate includes a second surface opposite to the first surface, the second surface including a first solder portion and a second solder portion for soldering,
• wherein the first terminal is soldered to the first solder portion,
• wherein the second terminal is soldered to the second solder portion, and
• wherein the control circuit includes a surface mounting component mounted on the second surface,
• wherein, as viewed in a direction perpendicular to the second surface, the surface mounting component is disposed inside an outer shape of the transformer, and
• wherein a pattern of the control circuit passes between the first solder portion and the second solder portion.