Electronic circuit control element with tap element

• US 8,611,108 B2
• Filed: 08/09/2012
• Issued: 12/17/2013
• Est. Priority Date: 05/27/2003
• Status: Expired due to Fees

• Current Assignee: Power Integrations Incorporated
• Original Assignee: Power Integrations Incorporated
• Inventors: Disney, Donald R.
• Primary Examiner(s): Vu, Bao Q
• Application Number:
  US13/571,209
• Publication Number:
  US 20120314453A1
• Time in Patent Office: 495 Days
• Field of Search: 363/21.1, 363/21.04, 363/21.12, 363/18, 363/19, 363/20
• US Class Current: 363/21.1
• CPC Class Codes: G05F 1/14 using tap transformers or tap changing inductors as final control devices
• CPC Class Codes: H01L 29/0634 Multiple reduced surface field (multi-RESURF) structures, e.g. double RESURF, charge compensation, cool, superjunction (SJ), 3D-RESURF, composite buffer (CB) structures
• CPC Class Codes: H01L 29/0653 adjoining the input or output region of a field-effect device, e.g. the source or drain region
• CPC Class Codes: H01L 29/0847 of field-effect transistors with insulated gate H01L29/0653 takes precedence; with a passive supplementary region between source or drain and substrate related to punch-through, capacity or isolation phenomena H01L29/1079; with LDD or DDD structure H01L29/7833; for thin film transistors H01L29/78618
• CPC Class Codes: H01L 29/407 Recessed field plates, e.g. trench field plates, buried field plates
• CPC Class Codes: H01L 29/42368 the thickness being non-uniform
• CPC Class Codes: H01L 29/7802 Vertical DMOS transistors, i.e. VDMOS transistors
• CPC Class Codes: H01L 29/7803 structurally associated with at least one other device assemblies H01L25/00; integrated circuits H01L27/00
• CPC Class Codes: H01L 29/7813 with trench gate electrode, e.g. UMOS transistors trench gate electrodes per se H01L29/4236
• CPC Class Codes: H02M 1/0009 Devices or circuits for detecting current in a converter
• CPC Class Codes: H02M 1/36 Means for starting or stopping converters
• CPC Class Codes: H02M 3/335 using semiconductor devices only
• CPC Class Codes: H02M 3/33507 with automatic control of the output voltage or current, e.g. flyback converters H02M3/33561, H02M3/33569 take precedence
• CPC Class Codes: H02M 3/33553 with galvanic isolation between input and output of both the power stage and the feedback loop
• CPC Class Codes: H02M 3/33561 having more than one ouput with independent control

Abstract

An example control element for use in a power supply includes a high-voltage transistor and a control circuit to control switching of the high-voltage transistor. The high-voltage transistor includes a drain region, source region, tap region, drift region, and tap drift region, all of a first conductivity type. The transistor also includes a body region of a second conductivity type. An insulated gate is included in the transistor such that when the insulated gate is biased a channel is formed across the body region to form a conduction path between the source region and the drift region. A voltage at the tap region with respect to the source region is substantially constant and less than a voltage at the drain region with respect to the source region in response to the voltage at the drain region exceeding a pinch off voltage.

Claims

1. A control element for use in a power supply, comprising:

a high-voltage transistor, including;

a drain region of a first conductivity type;

a source region of the first conductivity type;

a tap region of the first conductivity type;

a body region of a second conductivity type, the body region adjoining the source region;

a drift region of the first conductivity type extending from the drain region to the body region;

a tap drift region of the first conductivity type extending from the drain region to the tap region, wherein the tap region adjoins the tap drift region at an end of the tap drift region opposite the drain region; and

an insulated gate disposed such that when the insulated gate is biased a channel is formed proximate to the insulated gate across the body region to form a conduction path between the source region and the drift region; and

a control circuit coupled to the insulated gate and to the tap region to control switching of the high-voltage transistor to regulate an output of the power supply, wherein a voltage at the tap region with respect to the source region is substantially constant and less than a voltage at the drain region with respect to the source region in response to the voltage at the drain region exceeding a pinch off voltage.

2. The control element of claim 1, wherein the high-voltage transistor is configured to deplete the tap drift region of free charge carriers in response to the voltage at the drain region exceeding a pinch off voltage.

3. The control element of claim 1, wherein the voltage at the tap region tracks the voltage at the drain region in response to the voltage at the drain region being less than the pinch off voltage.

4. The control element of claim 1, wherein the high-voltage transistor further comprises a field plate disposed between the drift region and the tap drift region.

5. The control element of claim 1, wherein the voltage at the tap region is proportional to the voltage at the drain region in response to the voltage at the drain region being less than the pinch off voltage.

6. The control element of claim 1, wherein the voltage at the tap region is proportional to a current flowing through the high-voltage transistor between the drain and source regions in response to the voltage at the drain region being less than the pinch off voltage.

7. The control element of claim 1, wherein the high-voltage transistor and the control circuit are packaged together in a single integrated circuit.

8. The control element of claim 1, wherein the first conductivity type includes N type semiconductor material and wherein the second conductivity type includes P type semiconductor material.

9. The control element of claim 8, wherein

the drain region is an N+ doped region;

the source region is an N+ doped region;

the tap region is an N+ doped region;

the body region is a P doped region;

the drift region is an N−

doped region; and

the tap drift region is an N−

doped region.

10. A power supply, comprising:

an energy transfer element;

a control element coupled to the energy transfer element to control a transfer of energy across the energy transfer element, wherein the control element includes;

a high-voltage transistor coupled to the energy transfer element, the high-voltage transistor including a drain terminal, a source terminal, a control terminal and a tap terminal; and

a control circuit coupled to the control terminal and the tap terminal of the high-voltage transistor to control switching of the high-voltage transistor, wherein a voltage at the tap terminal with respect to the source terminal of the high-voltage transistor is substantially constant and less than a voltage at the drain terminal with respect to the source region in response to the voltage at the drain region exceeding a pinch off voltage.

11. The power supply of claim 10, wherein the voltage at the tap terminal is proportional to a current flowing through the high-voltage transistor between the drain and source terminals in response to the voltage at the drain terminal being less than the pinch off voltage.

12. The power supply of claim 10, wherein the high-voltage transistor and the control circuit are packaged together in a single integrated circuit.

13. The power supply of claim 10, wherein the energy transfer element includes a primary winding and an output winding, and wherein the drain terminal of the high-voltage transistor is coupled to the primary winding.

14. A power supply, comprising:

an energy transfer element;

a high-voltage transistor coupled to the energy transfer element to control a transfer of energy across the energy transfer element, the high-voltage transistor including;

a drain region of a first conductivity type;

a source region of the first conductivity type;

a tap region of the first conductivity type;

a body region of a second conductivity type, the body region adjoining the source region;

a drift region of the first conductivity type extending from the drain region to the body region;

a tap drift region of the first conductivity type extending from the drain region to the tap region, wherein the tap region adjoins the tap drift region at an end of the tap drift region opposite the drain region; and

an insulated gate disposed such that when the insulated gate is biased a channel is formed proximate to the insulated gate across the body region to form a conduction path between the source region and the drift region,

wherein a voltage at the tap terminal with respect to the source terminal of the high-voltage transistor is to be substantially constant and less than a voltage at the drain terminal with respect to the source region in response to the voltage at the drain region exceeding a pinch off voltage.

15. The power supply of claim 14, wherein the high-voltage transistor is configured to deplete the tap drift region of free charge carriers in response to the voltage at the drain region exceeding a pinch off voltage.

16. The power supply of claim 14, wherein the voltage at the tap region is to track the voltage at the drain region in response to the voltage at the drain region being less than the pinch off voltage.

17. The power supply of claim 14, wherein the high-voltage transistor further comprises a field plate disposed between the drift region and the tap drift region.

18. The power supply of claim 14, wherein the voltage at the tap region is to be proportional to the voltage at the drain region in response to the voltage at the drain region being less than the pinch off voltage.

19. The power supply of claim 14, wherein the voltage at the tap region is to be proportional to a current flowing through the high-voltage transistor between the drain and source regions in response to the voltage at the drain region being less than the pinch off voltage.

20. The control element of claim 14, wherein the first conductivity type includes N type semiconductor material and wherein the second conductivity type includes P type semiconductor material.

21. The control element of claim 20, wherein

the drain region is an N+ doped region;

the source region is an N+ doped region;

the tap region is an N+ doped region;

the body region is a P doped region;

the drift region is an N−

doped region; and

the tap drift region is an N−

doped region.