SWITCHING POWER SUPPLY
First Claim
1. A switching power supply comprising:
- a first auxiliary power supply for causing a secondary winding;
a first auxiliary winding of a transformer to induce voltage by ON/OFF control of a switching element connected to a primary winding of the transformer,wherein the voltage induced by the secondary winding is smoothened to output a DC voltage, and the voltage induced by the first auxiliary winding is smoothened to charge a capacitor in the first auxiliary power supply;
a control circuit that starts the ON/OFF control of the switching element when a voltage of the capacitor becomes greater than or equal to a first threshold value, causing the secondary winding of the transformer and the first auxiliary winding to induce voltage by the ON/OFF control,wherein the control circuit stops the ON/OFF control when the voltage of the capacitor becomes smaller than or equal to a second threshold value smaller than the first threshold value;
an activation circuit for charging the capacitor with voltage from power supply input to the switching power supply; and
a determination unit for determining a lifespan of the switching power supply based on the voltage of the capacitor after the voltage of the capacitor becomes greater than or equal to the first threshold value.
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Accused Products
Abstract
A switching power supply includes a first auxiliary power supply for causing a first auxiliary winding of a transformer to induce voltage by ON/OFF control of a switching element connected to a primary winding of the transformer. The voltage induced by the first auxiliary winding charges a capacitor in the first auxiliary power supply. The switching power supply also includes a control circuit for starting and stopping the ON/OFF control of the switching element by comparing a voltage of the capacitor with a first threshold value, an activation circuit for charging the capacitor with voltage from the power supply input to the switching power supply, and a determination unit for determining a lifespan of the switching power supply based on the voltage of the capacitor after the voltage of the capacitor becomes greater than or equal to the first threshold value.
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Citations
18 Claims
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1. A switching power supply comprising:
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a first auxiliary power supply for causing a secondary winding; a first auxiliary winding of a transformer to induce voltage by ON/OFF control of a switching element connected to a primary winding of the transformer, wherein the voltage induced by the secondary winding is smoothened to output a DC voltage, and the voltage induced by the first auxiliary winding is smoothened to charge a capacitor in the first auxiliary power supply; a control circuit that starts the ON/OFF control of the switching element when a voltage of the capacitor becomes greater than or equal to a first threshold value, causing the secondary winding of the transformer and the first auxiliary winding to induce voltage by the ON/OFF control, wherein the control circuit stops the ON/OFF control when the voltage of the capacitor becomes smaller than or equal to a second threshold value smaller than the first threshold value; an activation circuit for charging the capacitor with voltage from power supply input to the switching power supply; and a determination unit for determining a lifespan of the switching power supply based on the voltage of the capacitor after the voltage of the capacitor becomes greater than or equal to the first threshold value. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
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Specification