Direct current power supply apparatus
A direct current power supply apparatus that converts direct current input voltage supplied from a direct current power supply and that outputs a direct current voltage at a different potential is shown. The apparatus includes a switching power supply apparatus and a current stabilizing circuit connected at a stage before or after the switching power supply apparatus. The switching power supply apparatus includes, an oscillating circuit in which a frequency is variable and that generates an oscillating signal to apply a switching frequency, and an oscillating control circuit that generates an oscillating control voltage or an oscillating control current that changes the frequency of the oscillating circuit to the frequency longer than the switching frequency.
1 . A direct current power supply apparatus that converts direct current input voltage supplied from a direct current power supply and that outputs a direct current voltage at a different potential, the direct current power supply apparatus comprising:
a switching power supply apparatus; and
a current stabilizing circuit,
wherein the current stabilizing circuit is connected at a stage before the switching power supply apparatus,
wherein the switching power supply apparatus includes:
an oscillating circuit in which a frequency is variable and that generates an oscillating signal to apply a switching cycle, and
an oscillating control circuit that generates an oscillating control voltage or an oscillating control current that changes the frequency of the oscillating circuit to the cycle longer than the switching cycle,
wherein the oscillating control circuit is configured to diffuse a switching frequency upward,
wherein the oscillating circuit is a voltage control oscillating circuit configured to be able to change an oscillating frequency according to an applied voltage,
wherein the oscillating control circuit is a triangular wave generating circuit that generates a triangular wave in which a voltage value gradually increases or gradually decreases, and
wherein the triangular wave generated by the triangular wave generating circuit is applied to the oscillating circuit as a voltage that changes the oscillating frequency.
2 . The direct current power supply apparatus according to claim 1 , further comprising,
a current bypass path that is connected between a current input terminal of the current stabilizing circuit and a current output terminal of the current stabilizing circuit,
a current switch element provided in a middle of the current bypass path, and
an operation switching circuit that generates a signal that controls on and off of the current switch element according to a signal or voltage from outside and generates a signal that controls the current switch element,
wherein the direct current power supply apparatus is configured to prioritize noise reduction when the current switch element is off and to prioritize avoiding decrease in output voltage when the current switch element is on.
3 . The direct current power supply apparatus according to claim 2 ,
wherein the oscillating control circuit is configured to switch between a first operation state in which the generated oscillating control voltage is changed and a second operation state in which the oscillating control voltage is fixed, and
wherein the operation switching circuit is configured to generate a signal to switch the operation states of the oscillating control circuit.