Flyback converter
A converter circuit is disclosed. The converter circuit includes a transformer and a primary circuit connected to the primary side of the transformer, where the primary circuit includes a first switch connected to a ground. The converter circuit also includes a second switch connected to the first switch, and a clamping capacitor connected to the second switch and to the input. The converter circuit also includes a secondary circuit connected to the secondary side of the transformer, where the secondary circuit includes a rectifying element, and an output capacitor connected to the rectifying element. In addition, the output capacitor has a substantial effect on resonance of the converter circuit.
1. A converter circuit, comprising:
an input;
a transformer having a primary side and a secondary side;
a primary circuit connected to the primary side of the transformer, wherein the primary circuit comprises:
a first switch connected to a ground,
a second switch connected to the first switch, and
a clamping capacitor, comprising:
a first terminal connected to the second switch, and
a second terminal connected to the input;
a secondary circuit connected to the secondary side of the transformer, wherein the secondary circuit comprises:
a rectifying switch, and
an output capacitor connected to the rectifying switch; and
one or more controllers configured to turn on and off the first and second switches, such that a voltage is generated across the output capacitor, wherein during a first interval the first switch is on and the second switch is off, wherein during a second interval the first switch is off and the second switch is on, and wherein the controller is configured to turn on and off the rectifying switch such that the converter circuit has a secondary synchronous rectification operation,
wherein during the second interval a current through the rectifying switch becomes substantially equal to zero less than two times regardless of: a) voltage at the input, b) average voltage across the output capacitor, and c) average current through the rectifying switch, and wherein at the end of the second interval a current through the rectifying switch is substantially zero.
2. The converter circuit of claim 1 , wherein the clamping capacitor has a substantial effect on resonance of the circuit.
3. The converter circuit of claim 1 , wherein the clamping capacitor has substantially no effect on resonance of the circuit.
4. The converter circuit of claim 1 , wherein the secondary circuit further comprises:
a second rectifying switch, and
a second output capacitor connected to the second rectifying switch,
wherein resonance of the converter circuit is affected by the second output capacitor.
5. The converter circuit of claim 1 , wherein the output capacitor is connected directly to a load.
6. The converter circuit of claim 1 , wherein the secondary circuit further comprises an LC filter connected to the output capacitor, wherein the LC filter is configured to generate a voltage output having less ripple than a ripple across the output capacitor.
7. A converter circuit, comprising:
an input;
a transformer having a primary side and a secondary side;
a primary circuit connected to the primary side of the transformer, wherein the primary circuit comprises:
a first switch connected to a ground,
a second switch connected to the first switch, and
a clamping capacitor, comprising:
a first terminal connected to the second switch, and
a second terminal connected to the input;
a secondary circuit connected to the secondary side of the transformer, wherein the secondary circuit comprises:
a rectifying element, and
an output capacitor connected to the rectifying element,
wherein the secondary circuit further comprises an LC filter connected to the output capacitor, wherein the LC filter is configured to generate a voltage output having less voltage ripple than a voltage ripple across the output capacitor, and wherein the capacitance of the capacitor of the LC filter is greater than the capacitance of the output capacitor.
8. The converter circuit of claim 7 , wherein the rectifying element comprises a diode.
9. The converter circuit of claim 7 , wherein the rectifying element comprises a rectifying switch.
10. The converter circuit of claim 7 , wherein the secondary circuit further comprises:
a second rectifying element, and
a second output capacitor connected to the second rectifying
element,
wherein resonance of the converter circuit is affected by the second output capacitor.
11. The converter circuit of claim 7 , wherein the clamping capacitor has a substantial effect on resonance of the circuit.
12. The converter circuit of claim 7 , wherein the clamping capacitor has substantially no effect on resonance of the converter circuit.