DC-DC converter with overvoltage protection

Patent metadata

Field	Value
Publication number	US-10020746-B2
Application number	US-201715678243-A
Country	US
Kind code	B2
Filing date	Aug 16, 2017
Priority date	Feb 17, 2015
Publication date	Jul 10, 2018
Grant date	Jul 10, 2018

Abstract

A DC-DC converter includes a filter circuit, a full-bridge circuit connected to the filter circuit, and a transformer having a primary winding and a secondary winding, the primary winding being connected to the full-bridge circuit. The full-bridge circuit includes first to fourth semiconductor switches. First to fourth overvoltage protection circuits are associated with the first to fourth semiconductor switches, respectively. Each of the overvoltage protection circuits is connected in parallel its associated semiconductor switch.

First claim

The invention claimed is:

1. A DC-DC converter, comprising:
a filter circuit;
a full-bridge circuit connected to the filter circuit, the full-bridge circuit including first to fourth semiconductor switches, the first and second semiconductor switches being connected in series to form a first series connected circuit, the third and fourth semiconductor switches being connected in series to form a second series connected circuit, the first and second series connected circuits being coupled in parallel to one another, each of the semiconductor switches having a source and a drain and an associated design parasitic capacitance between its source and drain;
first to fourth overvoltage protection circuits associated with the first to fourth semiconductor switches, respectively, each of the overvoltage protection circuits being connected in parallel with its associated semiconductor switch, each of the overvoltage protection circuits having a capacitance equal to the design parasitic capacitance of its associated semiconductor switch within an error range of ±5%; and
a transformer having a primary winding and a secondary winding, the primary winding being connected to the full-bridge circuit,
wherein each of the overvoltage protection circuits is made up of one or more capacitors.

2. A DC-DC converter, comprising:
a filter circuit;
a full-bridge circuit connected to the filter circuit, the full-bridge circuit including first to fourth semiconductor switches, the first and second semiconductor switches being connected in series to form a first series connected circuit, the third and fourth semiconductor switches being connected in series to form a second series connected circuit, the first and second series connected circuits being coupled in parallel to one another, the first and third semiconductor switches each having a source and a drain and a respective design parasitic capacitance between its source and drain;
first to fourth overvoltage protection circuits associated with the first to fourth semiconductor switches, respectively, each of the overvoltage protection circuits being connected in parallel with its associated semiconductor switch, the first and third overvoltage protection circuits having a capacitance equal to the design parasitic capacitance of its associated semiconductor switch within an error range of ±5%; and
a transformer having a primary winding and a secondary winding, the primary winding being connected to the full-bridge circuit,
wherein the second and fourth semiconductor switches each comprise:
a respective resistor and electronic switch connected in series with each other and in parallel with its associated semiconductor switch; and
a respective switching circuit that turns on the respective electronic switch when a voltage applied to its associated semiconductor switch is greater than or equal to a respective threshold.

3. The DC-DC converter of claim 2 , wherein the respective threshold is less than a withstand voltage of its associated semiconductor switch.

4. The DC-DC converter of claim 3 , wherein the respective threshold is less than a value at which its associated semiconductor switch would be damaged.

5. The DC-DC converter of claim 2 , wherein each of the overvoltage protection circuits has a capacitance equal to a design parasitic capacitance of its associated semiconductor switch within an error range of ±5%.

6. A DC-DC converter, comprising:
(a) a filter circuit;
(b) a full-bridge circuit connected to the filter circuit, the full-bridge circuit including first to fourth semiconductor switches, the first and second semiconductor switches being connected in series to form a first series connected circuit, the third and fourth semiconductor switches being connected in series to form a second series connected circuit, the first and second series connected circuits being coupled in parallel to one another;
(c) first to fourth overvoltage protection circuits associated with the first to fourth semiconductor switches, respectively, each of the overvoltage protection circuits being connected in parallel with its associated semiconductor switch and comprising:
(i) a respective resistor and electronic switch connected in series with each other, the series connected resistor and electronic switch being connected in parallel with its associated semiconductor switch; and
(ii) a respective switching circuit that turns on the respective electronic switch when a voltage applied to its associated semiconductor switch is greater than or equal to a respective threshold that is less than a withstand voltage of its associated semiconductor switch and less than a value at which its associated semiconductor switch would be damaged; and

(d) a transformer having a primary winding and a secondary winding, the primary winding being connected to the full-bridge circuit.

7. A DC-DC converter, comprising:
a filter circuit;
a half-bridge circuit connected to the filter circuit, the half-bridge circuit including first and second semiconductor switches connected in series to form a first series connected circuit and first and second capacitors connected in series with each other for form a second series connected circuit, the first and second series connected circuits being connected in parallel with one another, the first and second semiconductor switches each having a source and a drain and a respective design parasitic capacitance between its source and drain;
first and second overvoltage protection circuits associated with the first and second semiconductor switches, respectively, each of the overvoltage protection circuits being connected in parallel with its associated semiconductor switch, at least one of the overvoltage protection circuits having a capacitance equal to a design parasitic capacitance of its associated semiconductor switch within an error range of ±5%; and
a transformer having a primary winding and a secondary winding, the primary winding being connected to the full-bridge circuit,
wherein the first semiconductor switch has a capacitance equal to a design parasitic capacitance of its associated semiconductor switch within an error range of ±5%, and
wherein the second semiconductor switch comprises:
(i) a respective resistor and electronic switch connected in series with each other, the series connected resistor and electronic switch being connected in parallel with its associated semiconductor switch; and
(ii) a respective switching circuit that turns on the respective electronic switch when a voltage applied to its associated semiconductor switch is greater than or equal to a respective threshold.

8. The DC-DC converter of claim 7 , wherein the respective threshold is less than a withstand voltage of the second semiconductor switch.

9. The DC-DC converter of claim 8 , wherein the respective threshold is less than a value at which the second semiconductor switch would be damaged.

10. A DC-DC converter, comprising:
(a) a filter circuit;
(b) a half-bridge circuit connected to the filter circuit, the half-bridge circuit including first and second semiconductor switches connected in series to form a first series connected circuit and first and second capacitors connected in series with each other for form a second series connected circuit, the first and second series connected circuits being connected in parallel with one another;
(c) first and second overvoltage protection circuits associated with the first and second semiconductor switches, respectively, each of the overvoltage protection circuits being connected in parallel with its associated semiconductor switch and comprising:
(i) a respective resistor and electronic switch connected in series with each, the ser

Assignees

• Murata Manufacturing Co

Inventors

• Horii Hiroyuki
• Ueki Koichi

Classifications

• H03H7/0115

  comprising only inductors and capacitors (H03H7/075, H03H7/09, H03H7/12, H03H7/13 take precedence) · CPC title

• H02M1/32

  Means for protecting converters other than automatic disconnection · CPC title

• H02M3/33523 Primary

  with galvanic isolation between input and output of both the power stage and the feedback loop · CPC title

• H02M1/08

  Circuits specially adapted for the generation of control voltages for semiconductor devices incorporated in static converters · CPC title

• H02M1/344

  Active dissipative snubbers · CPC title