Power supply with reduced switching losses by decreasing the switching frequency
View Patent ↗A power source device includes an input terminal, a first switching element connected to the input terminal, a second switching element connected to the first switching element, a transformer having a primary coil connected to a connecting node between the first and second switching elements, a low-pass filter including a series body of a coil and a capacitor connected to a secondary coil of the transformer, an output terminal connected to a connecting node between the coil and the capacitor, a comparator having a first input terminal connected to the output terminal, and an alternating signal generator connected to a second terminal of the comparator. An output terminal of the comparator is connected to each control terminal of the first switching element and the second switching element via the temporary amplitude generation permissible section.
1. A power source device comprising:
an input terminal;
a first switching element connected to the input terminal;
a second switching element connected to the first switching element;
a transformer having a primary coil connected to a connecting node between the first switching element and the second switching element;
a low-pass filter including a series body of a coil and a capacitor, which are connected to a secondary coil of the transformer;
an output terminal connected to a connecting node between the coil and the capacitor;
a comparator having a first input end connected to the output terminal; and
an alternating signal generator connected to a second input end of the comparator,
wherein an output terminal of the comparator is connected to each control terminal of the first switching element and the second switching element via a temporary amplitude generation permissible section; and
wherein the temporary amplitude generation permissible section comprises:
a pulse generator;
a first flip-flop circuit having a clock pulse input terminal connected to the pulse generator; and
a second flip-flop circuit having a clock pulse input terminal connected to the pulse generator; and
wherein the output terminal of the comparator is connected to each clear input terminal of the first flip-flop circuit and the second flip-flop circuit.
2. The power source device of claim 1 , wherein an output terminal of the first flip-flop circuit is connected to a control terminal of the first switching element and an output terminal of the second flip-flop circuit is connected to a control terminal of the second switching element.
3. A power source device comprising
an input terminal;
a first switching element connected to the input terminal;
a second switching element connected to the first switching element;
a low-pass filter including a series body of a coil and a capacitor, which are connected to a connecting node between the first switching element and the second switching element;
a transformer having a primary coil connected to a connecting node between the coil and the capacitor;
an output terminal connected to a secondary coil of the transformer;
a comparator having a first input end connected to the output terminal; and
an alternating signal generator connected to a second input end of the comparator,
wherein an output terminal of the comparator is connected to each control terminal of the first switching element and the second switching element via a temporary amplitude generation permissible section; and
wherein the temporary amplitude generation permissible section comprises:
a pulse generator;
a first flip-flop circuit having a clock pulse input terminal connected to the pulse generator; and
a second flip-flop circuit having a clock pulse input terminal connected to the pulse generator; and
wherein the output terminal of the comparator is connected to each clear input terminal of the first flip-flop circuit and the second flip-flop circuit.
4. The power source device of claim 3 , wherein an output terminal of the first flip-flop circuit is connected to a control terminal of the first switching element and an output terminal of the second flip-flop circuit is connected to a control terminal of the second switching element.