| 摘要 |
<p>PURPOSE:To widen an action guarantee power area by synchronizing the boosting action of a boosting circuit with the ON action of a switching element based on the detected result of a deciding circuit for the input of a voltage exceeding a threshold voltage. CONSTITUTION:When the output level of a boosting circuit BOOST is increased in accordance with a boosting ratio, a deciding circuit SENSE detects by exceeding the prescribed threshold and a control signal is inverted to an H level. Then, an AND gate AND is synchronized to the H level, the accumulated voltage of a capacity element C2 is rised, and a switch MOSFETQ3 is turned on. Thus, the output node of the circuit BOOST is leaked to a power voltage vdd and goes to the threshold voltage or below. Therefore, since the level of the boosting voltage is stepped down by a leaking circuit LEAK forcibly, the gate destruction of the MOSFET can be prevented beforehand. At the time of screening, the action guarantee power area by the power voltage supplied from the external part can be widened.</p> |
