| 摘要 |
PURPOSE:To stably control a power source at a high speed by using a power MOSFET as a switching element of a switching regulator, and providing a switch for discharging a gate stored charge when the MOSFET is OFF. CONSTITUTION:In a power source of switching regulator type for obtaining the desired output voltage in the secondary coil L13 by continuously controlling a current flowing to the primary side coil L11 of a transformer 4, a surface oxide film field effect transistor (power MOSFET) Q12 is used as the switching element connected in series with the coil L11. A switch Q12 for discharging a gate stored charge by turning ON when the control signal Vp of the Q13 is interrupted is provided at the gate of the transistor Q13. Thus, a current interrupting control at high speed can be performed, and the transistor Q13 can be effectively protected against its damage.
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