| 摘要 |
PROBLEM TO BE SOLVED: To provide a step-up converter whose output is not supplied with voltage, when the operation of the control circuit to turn on or turn off a switching element is in stoppage. SOLUTION: In a step-up converter, where a choke coil 3 and a reverse flow blocking diode 4 are connected in series between an input end 10 and an output end 20, and a switching transistor 1 is connected between the junction between the choke coil 3 and the reverse flow checking diode 4 and a ground, and a switching control circuit 2 is connected to the control terminal of the switching transistor 1, and a capacitor 5 is connected between the reverse flow blocking diode 4 and the ground, an output control circuit 8, which monitors the difference between a stepped-up DC voltage Vout and an input DC voltage Vin and turns on or turns off the output, is connected additionally between the junction between the reverse flow checking diode 4, the capacitor 5 and the output end 20.
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