Patent ID: 11936302
Assignee: FUJI ELECTRIC CO., LTD.
Field: Electrical machinery, apparatus, energy (Electrical engineering)
Classification: CPC H  G  Y | IPC G  H

Claim 8:
9. A power supply circuit, comprising:
a transformer including a primary coil provided on a primary side of the power supply circuit and a secondary coil provided on a secondary side of the power supply circuit;
a switching device configured to control a current in the primary coil; and
a switching control circuit configured to control switching of the switching device, wherein
the power supply circuit is configured to generate, on the secondary side thereof, an output voltage at a target level; and
the switching control circuit includes:
an oscillator circuit configured to output an oscillator signal to drive the switching device,
a driver circuit configured to drive the switching device in response to the oscillator signal,
a pulse generator circuit configured to generate a pulse signal,
a temperature voltage generator circuit configured to
generate a detection voltage corresponding to a temperature of the switching control circuit, based on a predetermined constant current, when the pulse signal is at a first level, and
stop generating the detection voltage, when the pulse signal is at a second level, and

an output circuit configured to output a detection signal indicating whether the temperature is higher than a predetermined temperature based on the detection voltage, during a period of time between
a first time that is a predetermined time period after the pulse signal reaches the first level,

and
a second time at which the pulse signal
switches from the first level to the second level, the pulse signal remaining in the first level in the period of time, wherein
the oscillator circuit, upon receiving the detection signal indicative that the temperature is higher than the predetermined temperature, causes a switching operation of the switching device to stop.