POWER SUPPLY DEVICE, AND METHOD OF SETTING THRESHOLD FOR POWER SUPPLY DEVICE

To provide a power supply device in which a threshold value for determining an overload current is set for each device and used for an actual overload current determination.SOLUTION: A power supply device (DC/DC converter 1) includes: a current detecting unit 22 that detects output current flowing to a load device 3; a comparison unit 23 that determines an existence of overload current by comparing the detected output current with a threshold value; and a control circuit 20 that controls the output current to be equal to or less than the maximum allowable current of the load device 3. When a reference current that is 1/n (n is a number of 2 or more) of the maximum allowable current is passed through the load device 3, a digital value that corresponds to the current and is monotonously and discretely time-varied is inputted to the comparison unit 23 instead of the threshold value. The control circuit 20 sets as the threshold value a value obtained by multiplying a digital vale by n times when the output of the comparison unit 23 is switched according to the comparison of the reference current and the digital value.SELECTED DRAWING: Figure 1 【課題】過電流を判定するための閾値を装置毎に設定して実際の過電流判断に用いる電源装置を提供する。【解決手段】電源装置（ＤＣ／ＤＣコンバータ１）は、負荷装置３を流れる出力電流を検出する電流検出部２２と、検出された出力電流を閾値と比較して過電流の有無を判定する比較器２３と、出力電流を負荷装置３の最大許容電流以下に制御する制御回路２０と、を備える。最大許容電流のｎ分の１（ｎは２以上の数）となる基準電流を負荷装置３に流しているときに、比較器２３に閾値に代えて、電流と対応して単調に且つ離散的に時間変化するデジタル値を入力する。制御回路２０は、基準電流とデジタル値との比較により比較器２３の出力が切り替わったときのデジタル値をｎ倍した値を、閾値に設定する。【選択図】図１