| 摘要 |
PURPOSE:To prevent damage to transistors (TRs) by using a TR to detect an overcurrent flowing to a switching TR intermitting an output current and controlling the switching TR via a capacitor thereby decreasing the average current. CONSTITUTION:When a switching TR 1 is turned on in response to an input signal from a terminal 1, a current is supplied to a load Rl and the current is detected by a TR 2. Then the TR 2 is turned on at overcurrent, a TR 3 is turned on, a capacitor Cl is charged and the TR 1 is turned off. The TR 3 is turned off in succession to the TR2 by a charging voltage across the capaci tor C1 and the TR 1 is turned on. If the overcurrent state is consecutive, the similar repetition is applied, the average current flowing to the TR1 is decreased and the damage of the TR1 due to overcurrent is prevented.
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