| 摘要 |
<p>This invention addresses the problem of providing a small-form-factor, low-cost overvoltage protection circuit that protects equipment from momentary excessive voltages and a power conversion device provided with said overvoltage protection circuit. In said overvoltage protection circuit (50), normally, a switch (11) is on, closing a bypass circuit (35), so no power is consumed in an impedance circuit (20), preventing a voltage being applied to equipment (30) from decreasing by an amount equal to the voltage drop across said impedance circuit (20). When an overvoltage occurs, the switch (11) turns off such that the voltage applied to the equipment (30) is reduced by an amount equal to the voltage drop corresponding to the impedance (Z) of the impedance circuit (20), making it possible to protect said equipment (30) from the overvoltage. Also, a second switch (12) opens a power-supply line (901), stopping the impedance circuit (20) from consuming power. This makes it possible to prevent overheating of the impedance circuit (20) and reduce the power rating.</p> |
