Power converter with tank circuit and over-voltage protection
View Patent ↗In one implementation, a power converter with over-voltage protection includes a power switch coupled to a power supply through a tank circuit, and a control circuit coupled to a gate of the power switch. The control circuit is configured to turn the power switch OFF based on a current from the tank circuit, thereby providing the over-voltage protection to the power converter. In one implementation, the power converter is a class-E power converter. In one implementation, the control circuit is configured to sense the current from the tank circuit based on a voltage drop across a sense resistor coupled to the power switch.
1. A power converter with over-voltage protection, the power converter comprising:
a power switch coupled to a power supply through a tank circuit, the tank circuit including an inductor and a capacitor coupled in parallel with each other, between the power supply and the power switch;
a control circuit coupled to a gate of the power switch;
a first sense resistor coupled in series with the power switch between a first load path terminal of the power switch and ground; and,
a second sense resistor coupled between a second load path terminal of the power switch and ground, wherein the control circuit is configured to
turn the power switch OFF based on a voltage across the first sense resistor, and
turn the power switch ON based on a voltage across the second sense resistor.
2. The power converter of claim 1 , wherein the control circuit is configured to turn the power switch ON when the voltage across the second sense resistor is substantially zero.
3. The power converter of claim 1 , wherein the power converter is a class-E power converter.
4. The power converter of claim 1 , wherein the power switch comprises a group IV insulated-gate bipolar transistor (IGBT).
5. The power converter of claim 1 , wherein the power switch comprises a group IV bipolar junction transistor (BJT).
6. The power converter of claim 1 , wherein the power switch comprises a group IV metal-oxide-semiconductor field-effect transistor (MOSFET).
7. The power converter of claim 1 , wherein the power switch comprises a group III-V heterostructure field-effect transistor (HFET).
8. The power converter of claim 1 , wherein the power converter is part of an induction heating (IH) cooktop.
9. A power converter with over-voltage protection, the power converter comprising:
a rectifier circuit coupled to an alternating current (AC) source to provide a power supply for a tank circuit;
a power switch coupled to the power supply through the tank circuit, the tank circuit including an inductor and a capacitor coupled in parallel with each other, between the power supply and the power switch;
a sense resistor coupled in series with the power switch between a first load path terminal of the power switch and ground;
a voltage divider electrically coupled between a second load path terminal of the power switch and ground; and
a control circuit configured to receive feedback from the sense resistor and from the voltage divider, wherein
the control circuit is configured to
turn the power switch OFF when a current through the sense resistor reaches a predetermined current threshold, and
turn the power switch ON when a voltage of the voltage divider is below a predetermined voltage threshold.
10. The power converter of claim 9 , wherein the control circuit is configured to turn the power switch ON when a current through the power switch is substantially zero.
11. The power converter of claim 9 , wherein the power converter is a class-E power converter.
12. The power converter of claim 9 , wherein the control circuit is configured to sense the current from the tank circuit based on a voltage drop across the sense resistor.
13. The power converter of claim 9 , wherein the power switch comprises a group IV insulated-gate bipolar transistor (IGBT).
14. The power converter of claim 9 , wherein the power switch comprises a group IV bipolar junction transistor (BJT).
15. The power converter of claim 9 , wherein the power switch comprises a group IV metal-oxide-semiconductor field-effect transistor (MOSFET).
16. The power converter of claim 9 , wherein the power switch comprises a group III-V heterostructure field-effect transistor (HFET).
17. The power converter of claim 9 , wherein the power converter is part of an induction heating (IH) cooktop.
18. The power converter of claim 9 , wherein the voltage divider comprises a resistive voltage divider.
19. A power converter comprising:
a resonant tank coupled between a supply terminal and a first load path terminal of a power transistor;
a first sense resistor coupled between a second load path terminal of the power transistor and ground;
a second sense resistor coupled between the first load path terminal and ground; and
a control circuit coupled to a gate of the power transistor, the control circuit configured to
turn off the power transistor when a voltage across the first sense resistor is higher than a first reference voltage, and
turn on the power transistor when a voltage across the second sense resistor is lower than a second reference voltage.
20. The power converter of claim 19 , wherein the control circuit comprises:
a first comparator coupled to the first sense resistor;
a second comparator coupled to the second sense resistor; and
a first flip-flop with inputs coupled to the first comparator and the second comparator and an output coupled to the gate of the power transistor.
21. The power converter of claim 19 , further comprising the power transistor.