Inverter circuit with switch circuit having two transistors operating alternatively

• US 7,787,273 B2
• Filed: 12/21/2007
• Issued: 08/31/2010
• Est. Priority Date: 12/22/2006
• Status: Active Grant

• Current Assignee: InnoLux Corporation
• Original Assignee: Innocom Technology Limited, Chi Mei Innolux Corporation (InnoLux Corporation)
• Inventors: Lu, Jian-Hui, Zhou, Tong
• Primary Examiner(s): Berhane; Adolf
• Assistant Examiner(s): Mehari; Yemane
• Application Number:
  US12/004,850
• Publication Number:
  US 20080151587A1
• Time in Patent Office: 984 Days
• Field of Search: 363/55, 363/56, 363/71, 363/75, 363/97
• US Class Current: 363/133
• CPC Class Codes: H02M 1/009 having two or more independently controlled outputs for DC-DC converter with intermediate AC H02M3/33561
• CPC Class Codes: H02M 7/5381 Parallel type

Abstract

An exemplary inverter circuit (2) includes a first switch circuit (22) including a first transistor (221) and a second transistor (222); a second switch circuit (23) including a third transistor (231) and a fourth transistor (232); and a pulse width modulation circuit (21) including a first output terminal (211) and a second output terminal (212). A gate electrode of the first transistor is connected to the first output port. A gate electrode of the second transistor is connected to the second output port. A gate electrode of the third transistor is connected to the first output port. A gate electrode of the fourth transistor is connected to the second output port. A drain electrode of the third transistor is connected to a drain electrode of the first transistor, and a drain electrode of the fourth transistor is connected to a drain electrode of the second transistor.

Claims

1. An inverter circuit, comprising:

a direct current input terminal connected to a direct current power supply;

a first transformer comprising a first primary winding, a second primary winding, and a secondary winding configured for outputting an alternating current voltage;

a second transformer comprising a third primary winding, a fourth primary winding, and a secondary winding configured for outputting an alternating current voltage;

a pulse width modulation circuit comprising a first output terminal to output a first square wave signal and a second output terminal to output a second square wave signal with an inverse phase relative to the first square wave signal;

a first switch circuit comprising a first transistor and a second transistor; and

a second switch circuit comprising a third transistor and a fourth transistor;

wherein a gate electrode of the first transistor is connected to the first output terminal, and a source electrode of the first transistor is connected to ground;

a gate electrode of the second transistor is connected to the second output terminal, and a source electrode of the second transistor is connected to ground;

a gate electrode of the third transistor is connected to the first output terminal, and a source electrode of the third transistor is connected to ground;

a gate electrode of the fourth transistor is connected to the second output terminal, and a source electrode of the fourth transistor is connected to ground;

a drain electrode of the third transistor is connected to a drain electrode of the first transistor, and a drain electrode of the fourth transistor is connected to a drain electrode of the second transistor;

the first primary winding and the second primary winding share a first tap, the first tap is connected to the direct current input terminal, the other tap of the first primary winding is connected to the drain electrode of the first transistor, and the other tap of the second primary winding is connected to the drain electrode of the second transistor; and

the third primary winding and the fourth primary winding share a second tap, the second tap is connected to the direct current input terminal, the other tap of the third primary winding is connected to the drain electrode of the first transistor, and the other tap of the third primary winding is connected to the drain electrode of the second transistor.

2. The inverter circuit as claimed in claim 1, further comprising a first filter circuit and a second filter circuit, wherein the first filter circuit is connected between the first tap and ground, and the second filter circuit is connected between the second tap and ground.

3. The inverter circuit as claimed in claim 1, wherein the first switch circuit is installed in a first chip and the second switch circuit is installed in a second chip.

4. The inverter circuit as claimed in claim 1, wherein the first transistor, the second transistor, the third transistor, and the fourth transistor are N-channel metal-oxide-semiconductor field-effect transistors.

5. The inverter circuit as claimed in claim 2, wherein each filter circuit comprises a resistor and a capacitor connected in series.

6. The inverter circuit as claimed in claim 5, wherein the direct current input terminal is connected to ground via a capacitor.

7. The inverter circuit as claimed in claim 6, wherein the drain electrode of the fourth transistor is connected to ground via a capacitor.

8. An inverter circuit, comprising:

a direct current input terminal connected to a direct current power supply;

a first switch circuit comprising a first transistor and a second transistor;

a second switch circuit comprising a third transistor and a fourth transistor, wherein source electrodes of the first, second, third and fourth transistors are grounded, a drain electrode of the third transistor is connected to a drain electrode of the first transistor, and a drain electrode of the fourth transistor is connected to a drain electrode of the second transistor;

a first transformer comprising a first primary winding, a second primary winding, and a secondary winding configured for outputting an alternating current voltage, wherein the first primary winding and the second primary winding share a first tap, the first tap is connected to the direct current input terminal, the other tap of the first primary winding is connected to the drain electrode of the first transistor, and the other tap of the second primary winding is connected to the drain electrode of the second transistor;

a first filter circuit connected between the first tap and ground;

a second transformer comprising a third primary winding, a fourth primary winding, and a secondary winding configured for outputting an alternating current voltage, wherein the third primary winding and the fourth primary winding share a second tap, the second tap is connected to the direct current input terminal, the other tap of the third primary winding is connected to the drain electrode of the first transistor, and the other tap of the fourth primary winding is connected to the drain electrode of the second transistor;

a second filter circuit connected between the second tap and ground; and

a pulse width modulation circuit comprising a first output port configured for outputting a first square wave signal to turn on or turn off the first transistor and the third transistor and a second output port configured for outputting a second square wave signal to turn on or turn off the second transistor and the fourth transistor, wherein gate electrodes of the first and the third transistors are connected to the first output port, and gate electrodes of the second and the fourth transistors are connected to the second output port;

wherein phases of the first square wave signal and the second square wave signal are opposite;

when the first square wave signal is a high level and the second square wave signal is a low level, a first current path is formed sequentially through the direct current input terminal, a first parallel circuit formed by the first primary winding and the third primary winding, a second parallel circuit formed by the first transistor and the third transistor, and ground; and

when the first square wave signal is a low level and the second square wave signal is a high level, a second current path is formed sequentially through the direct current input terminal, a third parallel circuit formed by the second primary winding and the fourth primary winding, a fourth parallel circuit formed by the second transistor and the fourth transistor, and ground.

9. The inverter circuit as claimed in claim 8, wherein each of the first and second filter circuits comprises a resistor and a capacitor connected in series.

10. The inverter circuit as claimed in claim 8, wherein the first switch circuit is installed in a first chip and the second switch circuit is installed in a second chip.

11. The inverter circuit as claimed in claim 8, wherein the first transistor, the second transistor, the third transistor, and the fourth transistor are N-channel metal-oxide-semiconductor field-effect transistors.

12. The inverter circuit as claimed in claim 9, wherein the direct current input terminal is connected to ground via a capacitor.

13. The inverter circuit as claimed in claim 12, wherein the drain electrode of the fourth transistor is connected to ground via a capacitor.