Low forward voltage rectifier using capacitive current splitting

• US 10,038,383 B2
• Filed: 05/01/2015
• Issued: 07/31/2018
• Est. Priority Date: 10/29/2011
• Status: Active Grant

• Current Assignee: Littelfuse Incorporated
• Original Assignee: IXYS, LLC (Littelfuse Incorporated)
• Inventors: Seok, Kyoung Wook
• Primary Examiner(s): Berhane, Adolf
• Application Number:
  US14/701,532
• Publication Number:
  US 20150236601A1
• Time in Patent Office: 1,187 Days
• Field of Search: 363 2112, 363 2113, 363 2114, 363127, 363147
• CPC Class Codes: G05F 1/46 wherein the variable actually regulated by the final control device is dc G05F1/625 takes precedence
• CPC Class Codes: H01L 27/0664 Vertical bipolar transistor in combination with diodes
• CPC Class Codes: H02M 1/0048 Circuits or arrangements for reducing losses using snubbers H02M1/34
• CPC Class Codes: H02M 1/083 for the ignition at the zero crossing of the voltage or the current
• 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 3/33576 having at least one active switching element at the secondary side of an isolation transformer
• CPC Class Codes: H05K 13/00 Apparatus or processes specially adapted for manufacturing or adjusting assemblages of electric components
• CPC Class Codes: Y02B 70/10 Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes
• CPC Class Codes: Y10T 29/49117 Conductor or circuit manufacturing

Abstract

A Low Forward Voltage Rectifier (LFVR) circuit includes a bipolar transistor, a parallel diode, and a capacitive current splitting network. The LFVR circuit, when it is performing a rectifying function, conducts the forward current from a first node to a second node provided that the voltage from the first node to the second node is adequately positive. The capacitive current splitting network causes a portion of the forward current to be a base current of the bipolar transistor, thereby biasing the transistor so that the forward current experiences a low forward voltage drop across the transistor. The LFVR circuit sees use in as a rectifier in many different types of switching power converters, including in flyback, Cuk, SEPIC, boost, buck-boost, PFC, half-bridge resonant, and full-bridge resonant converters. Due to the low forward voltage drop across the LFVR, converter efficiency is improved.

Claims

1. A method of manufacture comprising:

(a) providing a first capacitor, a second capacitor, a bipolar transistor and a diode, such that the first capacitor is connected between a first node and a base of the bipolar transistor, such that the second capacitor is connected between the first node and a collector of the bipolar transistor, such that an anode of the diode is coupled to the collector of the bipolar transistor, and such that a cathode of the diode is coupled to an emitter of the bipolar transistor at a second node, wherein the first capacitor, the second capacitor, the bipolar transistor, and the diode are parts of a switching power converter circuit.

2. The method of manufacture of claim 1, wherein the bipolar transistor is a Reverse Bipolar Junction Transistor (RBJT).

3. The method of manufacture of claim 1, wherein the bipolar transistor has a reverse breakdown voltage of at least twenty volts.

4. The method of manufacture of claim 1, wherein the bipolar transistor and the diode are integrated onto a semiconductor die.

5. The method of manufacture of claim 1, wherein the second capacitor has a first terminal and a second terminal, wherein the first terminal of the second capacitor is coupled to the first node, wherein the first terminal of the second capacitor is also coupled to a terminal of the first capacitor, and wherein the second terminal of the second capacitor is coupled to the collector of the bipolar transistor.

6. The method of manufacture of claim 1, wherein the first capacitor has a capacitance that is substantially smaller than a capacitance of the second capacitor.

7. The method of manufacture of claim 1, wherein the switching power converter circuit is taken from a group consisting of:

a flyback converter, a Cuk converter, a SEPIC converter, a boost converter, a buck-boost converter, a power factor correction converter circuit, a half-bridge resonant converter, and a full-bridge resonant converter.

8. A switching power converter circuit comprising:

a bipolar transistor having a base, a collector, and an emitter; and

means for receiving a current from a first node and for capacitively splitting the current so that a first portion of the current is supplied by the means to the base of the bipolar transistor and so that a second portion of the current is supplied by the means to the collector of the bipolar transistor such that the means is coupled between the first node and the base and the collector of the bipolar transistor.

9. The switching power converter circuit of claim 8, wherein the means comprises:

a first capacitor coupled between the first node and the base of the bipolar transistor, and a second capacitor coupled between the first node and the collector of the bipolar transistor.

10. The switching power converter circuit of claim 9, wherein the first capacitor has a capacitance that is substantially smaller than a capacitance of the second capacitor.

11. The switching power converter circuit of claim 8, further comprising:

a diode having an anode and a cathode, wherein the anode is coupled to one of the collector and the emitter of the bipolar transistor, and wherein the cathode is coupled to the other of the collector and the emitter of the bipolar transistor.

12. The switching power converter circuit of claim 11, wherein the bipolar transistor and the diode are integrated onto a semiconductor die.

13. The switching power converter circuit of claim 8, wherein the first portion is substantially smaller than the second portion.

14. The switching power converter circuit of claim 8, wherein a magnitude of the first portion is a substantially fixed fraction of a magnitude of the second portion.

15. The switching power converter circuit of claim 8, wherein the bipolar transistor is a Reverse Bipolar Junction Transistor (RBJT).

16. The switching power converter circuit of claim 8, wherein the bipolar transistor has a reverse breakdown voltage of at least twenty volts.

17. The switching power converter circuit of claim 8, wherein the switching power converter circuit is taken from a group consisting of:

a flyback converter, a Cuk converter, a SEPIC converter, a boost converter, a buck-boost converter, a power factor correction converter circuit, a half-bridge resonant converter, and a full-bridge resonant converter.