CASCODE CONFIGURED SWITCHING USING AT LEAST ONE LOW BREAKDOWN VOLTAGE INTERNAL, INTEGRATED CIRCUIT SWITCH TO CONTROL AT LEAST ONE HIGH BREAKDOWN VOLTAGE EXTERNAL SWITCH

• US 20100328976A1
• Filed: 06/30/2009
• Published: 12/30/2010
• Est. Priority Date: 06/30/2009
• Status: Active Grant

• Current Assignee: Cirrus Logic Incorporated
• Original Assignee: Cirrus Logic Incorporated
• Inventors: Melanson, John L.
• Granted Patent: US 8,248,145 B2
• Time in Patent Office: Days
• US Class Current: 363/131
• CPC Class Codes: H02M 3/158 including plural semiconductor devices as final control devices for a single load
• CPC Class Codes: H03K 17/102 in field-effect transistor switches

Abstract

An electronic system includes a low breakdown voltage (LBV) switch internal to an integrated circuit controller to control conductivity of an external, high breakdown voltage (HBV) switch. In at least one embodiment, the internal LBV switch and a cascode configuration of the LBV and HBV switches allow the controller to control the LBV switch and the HBV switch using an internal (“on-chip”) control signal. In at least one embodiment, the LBV switch and the cascode configuration of the HBV switch also allows the controller to control the LBV and HBV switches with more accuracy and less parasitic losses relative to directly controlling the HBV switch. Thus, in at least one embodiment, the low breakdown voltage switch is fabricated as part of an integrated circuit controller, and the high breakdown voltage switch is fabricated separately and located external to the integrated circuit controller.

Claims

1. An apparatus comprising:

an integrated circuit controller to at least control a switching power converter, wherein the controller is configured to control the switching power converter by generating a switch control signal to control a first switch, wherein the first switch is internal to the controller, the integrated circuit includes a node to couple the first switch to a second switch in a cascode configuration, and a breakdown voltage of the first voltage switch is approximately less than or equal to one-half of a breakdown voltage of the second switch.

2. The apparatus of claim 1 wherein:

the first switch comprises a switch selected from a group consisting of a field effect transistor, a bipolar junction transistor, and an insulated gate bipolar transistor; and

the second switch comprises a switch selected from a group consisting of a field effect transistor, a bipolar junction transistor, and an insulated gate bipolar transistor.

3. The apparatus of claim 1 wherein the first switch and the second switch are identical types.

4. The apparatus of claim 1 wherein the first switch and the second switch are different types.

5. The apparatus of claim 1 wherein the controller is configured to control power factor correction of the switching power converter.

6. The apparatus of claim 1 wherein the controller is configured to generate the control signal to shape current in the switches.

7. The apparatus of claim 6 wherein the controller is configured to generate one or more intermediate steps of the switch control signal between an initial and final value of a pulse of the control signal to control the increase of the current in the switches.

8. The apparatus of claim 1 wherein the integrated circuit further comprises:

a first node to couple to a voltage supply;

a second node to couple to the first switch and the second switch; and

a diode coupled between the first node and the second node.

9. The apparatus of claim 8 wherein the first node is also for coupling to a bias node of the second switch.

10. The apparatus of claim 1 wherein the breakdown voltage of the first switch is approximately less than or equal to 30 V and the breakdown voltage of the second switch is approximately greater than or equal to 60 V.

11. A method comprising:

generating a switch control signal;

controlling conductivity of a first switch using the control signal; and

controlling conductivity of a second switch of a switching power converter with the first switch;

wherein a breakdown voltage of the first switch is approximately less than or equal to one-half of a breakdown voltage of the second switch.

12. The method of claim 11 wherein generating the switch control signal comprises generating the switch control signal with an integrated circuit controller, and the integrated circuit controller includes the first switch.

13. The method of claim 11 further comprising:

controlling power factor correction and output voltage regulation of a switching power converter using the switch control signal.

14. The method of claim 11 wherein:

the first switch comprises a switch selected from a group consisting of a field effect transistor, a bipolar junction transistor, and an insulated gate bipolar transistor; and

the second switch comprises a switch selected from a group consisting of a field effect transistor, a bipolar junction transistor, and an insulated gate bipolar transistor.

15. The method of claim 11 wherein the first switch and the second switch are identical types.

16. The method of claim 11 wherein the first switch and the second switch are different types.

17. The method of claim 11 wherein the first switch comprises a bipolar junction transistor and the second switch comprises a bipolar junction transistor.

18. The method of claim 11 wherein generating the switch control signal further comprises:

generating the control signal to shape current in the switches.

19. The method of claim 18 wherein generating the switch control signal further comprises:

generating one or more intermediate steps of the switch control signal between an initial and final value of a pulse of the control signal to control the increase of the current in the switches.

20. The method of claim 11 further comprising:

discharging a node coupled between the first switch and the second switch to a power supply after the low and second switches are turned “

off”

by the switch control signal.

21. The method of claim 11 wherein the breakdown voltage of the first switch is approximately less than or equal to 30 V and the breakdown voltage of the second switch is approximately greater than or equal to 60 V.

22. An apparatus comprising:

a switching power converter having a first switch to control an output voltage of the switching power converter; and

an integrated circuit controller, coupled to the first switch, to generate a switch control signal to control a second switch, wherein the second switch is internal to the controller, the integrated circuit includes a node to couple the second switch to the first switch of the switching power converter in a cascode configuration, and a breakdown voltage of the second switch is approximately less than or equal to one-half of a breakdown voltage of the first switch of the switching power converter.

23. The apparatus of claim 22 wherein the controller is configured to generate one or more intermediate steps of the switch control signal between an initial and final value of a pulse of the control signal to control the rise of the current in the switches.