Resonance operation of DC-DC converter using a point-of-load integrated circuit
A converter includes first and second input terminals; an integrated circuit (IC) that is a non-resonant, step-down, and point-of-load IC, that is connected to the first and second input terminals, and that includes a feedback terminal and switch-output terminal; a voltage-sense circuit connected to the feedback terminal and the switch-output terminal; a transformer that includes a primary winding connected to the switch-output terminal; a capacitor connected in series with the primary winding; a rectifier connected to a secondary winding of the transformer; and first and second output terminals connected to the rectifier. The converter is operated in a resonate mode.
1. A converter comprising:
first and second input terminals;
an integrated circuit (IC) that is a non-resonant, step-down, and point-of-load IC, that is connected to the first and second input terminals, and that includes a feedback terminal and switch-output terminal;
a voltage-sense circuit connected to the feedback terminal and the switch-output terminal;
a transformer that includes a primary winding connected to the switch-output terminal;
a capacitor connected in series with the primary winding;
a rectifier connected to a secondary winding of the transformer; and
first and second output terminals connected to the rectifier; wherein
the converter is operated in a resonate mode;
the voltage-sense circuit includes a voltage divider defined by first and second resistors connected in series with each other;
the first resistor is directly connected to the switch-output terminal; and
a node between the first and the second resistors is connected to the feedback terminal to keep a voltage on the feedback terminal constant.
2. The converter of claim 1 , wherein a signal received by the feedback terminal from the voltage-sense circuit causes the IC to provide a 50% duty cycle or an approximately 50% duty cycle.
3. The converter of claim 1 , wherein a resonant circuit defined by a leakage inductance of the primary winding and the capacitor resonates.
4. The converter of claim 1 , further comprising a pre-regulator connected to the first and the second input terminals.
5. The converter of claim 4 , wherein the pre-regulator includes:
pre-regulator IC that includes a feedback terminal and a switch-output terminal; and
a pre-regulator voltage-sense circuit that is connected to the switch-output terminal of the pre-regulator IC through an inductor and that is connected to the feedback terminal of the pre-regulator IC.
6. The converter of claim 5 , further including a feedback circuit connected to the first and the second output terminals and connected to the pre-regulator IC.
7. The converter of claim 6 , wherein the feedback circuit includes feedback IC connected to the first and the second output terminals.
8. The converter of claim 6 , wherein the feedback circuit includes an optocoupler.
9. The converter of claim 8 , wherein the optocoupler includes a photo transistor and a light-emitting diode.
10. The converter of claim 8 , wherein the optocoupler includes first and second capacitors.
11. The converter of claim 4 , further comprising a load compensation circuit.
12. The converter of claim 1 , wherein the rectifier is a full-bridge rectifier.
13. The converter of claim 12 , wherein the full-bridge rectifier is connected to an inductor.
14. The converter of claim 1 , wherein the rectifier includes a voltage-doubler circuit or a voltage-quadrupler circuit.
15. The converter of claim 1 , further comprising a capacitive divider connected to the primary winding.
16. A converter comprising:
first and second input terminals;
an integrated circuit (IC) that is a non-resonant, step-down, and point-of-load IC, that is connected to the first and second input terminals, and that includes a feedback terminal and switch-output terminal;
a voltage-sense circuit connected to the feedback terminal and the switch-output terminal;
a transformer that includes a primary winding connected to the switch-output terminal;
a capacitor connected in series with the primary winding;
a rectifier connected to a secondary winding of the transformer; and
first and second output terminals connected to the rectifier;
an additional IC that is a non-resonant, step-down, and point-of-load IC, that is connected to the first and second input terminals, and that includes a feedback terminal and switch-output terminal; wherein
the converter is operated in a resonate mode;
the IC and the additional IC are arranged in a phase-shift, full-bridge topology.
17. A converter comprising:
first and second input terminals;
an integrated circuit (IC) that is a non-resonant, step-down, and point-of-load IC, that is connected to the first and second input terminals, and that includes a feedback terminal and switch-output terminal;
a voltage-sense circuit that is connected to the feedback terminal and that is directly connected to the switch-output terminal;
a transformer that includes a primary winding connected to the switch-output terminal;
a capacitor connected in series with the primary winding;
a rectifier connected to a secondary winding of the transformer; and
first and second output terminals connected to the rectifier; wherein
the voltage-sense circuit includes a voltage divider defined by first and second resistors connected in series with each other;
the first resistor is directly connected to the switch-output terminal; and
a node between the first and the second resistors is connected to the feedback terminal to keep a voltage on the feedback terminal constant.
18. The converter of claim 17 , further comprising an inductor connected to the rectifier.