Cascaded diode circuit
By designing a cascaded diode circuit in high-power and high-performance circuits, using the combination of normally open transistors, low-voltage diodes and high-voltage diodes, the circuit cost increase caused by high-voltage silicon carbide transistors in the prior art is solved, and the circuit cost increase is achieved. Cost-performance circuit design with extremely low forward voltage and fast switching speed.
Patent Information
- Application Number
- CN202310942631.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2023-07-28
- Publication Date
- 2025-02-14
AI Technical Summary
In existing high-power and high-performance circuits, the use of high-voltage silicon carbide transistors leads to an increase in circuit costs and it is difficult to achieve a balance between performance and cost.
A cascaded diode circuit is designed, including normally open transistors, low voltage diodes and high voltage diodes, and the combination of these components achieves extremely low forward voltage drop and fast switching speeds.
A circuit design with extremely low forward voltage and fast switching speeds is achieved, providing a simple and cost-effective solution that reduces circuit costs while maintaining high performance.
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Figure CN119448991A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to a diode circuit, and more particularly to a cascaded diode circuit with an ultralow forward voltage drop. Background Art
[0002] For high power and / or high performance circuit applications, transistors such as GaN / SiC field effect transistors are expected to have high efficiency and high voltage operation. One popular design combines III-nitride transistors with silicon diodes to form a cascade diode circuit, which can be found in Yuan Li and Alex Q. Huang, “Huang-Pair: A New High Voltage Diode Concept and Its Demonstration”, IEEE Transactions on Power Electronics, vol. 36, no. 8, pp. 8653-8657, August 2021.
[0003] The circuit in the above reference uses a pair of silicon carbide transistors and a silicon diode. In order to achieve the IV behavior disclosed in the above reference, a high-voltage transistor is required. However, high-voltage silicon carbide transistors are quite expensive, which increases the cost of the circuit and makes it challenging to use in commercial applications.
[0004] Therefore, a simple and cost-effective circuit design is needed to satisfy the balance between performance and cost. Summary of the invention
[0005] According to one embodiment of the present disclosure, a cascade diode circuit is disclosed, which includes a normally-on transistor, a low voltage diode and a high voltage diode. The normally-on transistor has a gate, a drain and a source. The low voltage diode has a cathode connected to the source of the normally-on transistor and an anode connected to the gate of the normally-on transistor. The high voltage diode has a cathode connected to the drain of the normally-on transistor and an anode connected to a node between the normally-on transistor and the low voltage diode. The rated current or rated voltage of the normally-on transistor is equal to or less than the rated current or rated voltage of the high voltage diode.
[0006] In one embodiment, a breakdown voltage of the normally-on transistor is equal to or greater than a breakdown voltage of the high voltage diode.
[0007] In one embodiment, a breakdown voltage of the high voltage diode is greater than a breakdown voltage of the low voltage diode.
[0008] In one embodiment, an absolute value of a breakdown voltage of the low voltage diode is equal to or greater than a gate threshold voltage of the normally-on transistor.
[0009] In one embodiment, the normally-on transistor, the low voltage diode, and the high voltage diode satisfy the following relationship:
[0010] V L ≤V TR ≤V H
[0011] Among them, V TR Represents the rated voltage of the normally-on transistor, V L Indicates the rated voltage of the low voltage diode, V H Indicates the rated voltage of the high voltage diode.
[0012] In one embodiment, the rated voltage of the normally-on transistor is equal to or greater than a predetermined value, the rated voltage of the high voltage diode is equal to or greater than the predetermined value, and the rated voltage of the low voltage diode is equal to or less than the predetermined value.
[0013] In one embodiment, the rated current of the low voltage diode is equal to or less than the rated current of the high voltage diode.
[0014] In one embodiment, the rated current of the normally-on transistor is equal to or greater than a first predetermined value, the rated current of the low-voltage diode is equal to or greater than the first predetermined value, and the rated current of the high-voltage diode is equal to or greater than a second predetermined value, wherein the second predetermined value is greater than the first predetermined value.
[0015] In one embodiment, the rated current and rated voltage of the normally-on transistor are respectively equal to or less than the rated current and rated voltage of the high voltage diode.
[0016] In one embodiment, the normally-on transistor is a metal oxide semiconductor field effect transistor (MOSFET), a junction field effect transistor (JFET), or a high electron mobility transistor (HEMT).
[0017] Therefore, the cascade diode circuit provided in the present application can exhibit extremely low forward voltage and fast switching speed, and the combination of the normally-on transistor and the low-voltage diode provides a simple and cost-effective solution. BRIEF DESCRIPTION OF THE DRAWINGS
[0018] Figure 1 FIG. 4 is a schematic diagram of a cascade diode circuit according to an embodiment of the present invention.
[0019] Figure 2 FIG. 4 is a forward characteristic curve diagram of an embodiment of the present invention.
[0020] Figure 3A and Figure 3B For a cascade diode circuit according to an embodiment of the present invention, forward characteristic curves with different ratios are measured.
[0021] Figure 4 FIG. 1 is a diagram of a measured reverse characteristic curve of a cascade diode circuit according to an embodiment of the present invention. DETAILED DESCRIPTION
[0022] In this article, the terms used in the description of various embodiments are only for the purpose of describing specific examples, and are not intended to be limiting. Unless the context clearly indicates otherwise, or the number of elements is deliberately limited, the singular forms "one", "the" used herein may also include plural forms. Further, the terms "including" and / or "comprising" when used in this article indicate the presence of the described features, elements and / or components, but do not exclude the addition or presence of one or more other features, elements, components and / or their groups. Indefinite and definite articles should include plural and singular, unless the contrary is clearly seen from the context.
[0023] It should also be understood that when an element is referred to as being "connected" or "coupled" to another element, it can be directly connected or coupled to the other element, or there can be intervening elements. Conversely, when an element is referred to as being "directly connected" or "directly coupled" to another element, there are no intervening elements.
[0024] See also Figure 1 , is a schematic diagram of a cascode diode circuit according to an embodiment of the present invention. The cascode diode circuit 10 includes a normally on transistor 11, a low voltage diode 12 and a high voltage diode 13.
[0025] In one embodiment, the normally-on transistor 11 may be a normally-on high voltage wide band gap transistor (WBG transistor), which may be implemented by a metal-oxide-semiconductor field-effect transistor (MOSFET). For example, the normally-on transistor 11 may be a silicon carbide (SiC) transistor, a gallium nitride (GaN) transistor, an aluminum nitride (AlN) transistor, a diamond transistor, or any other transistor with a 2.5 eV band gap. The low voltage diode 12 has a low knee voltage (i.e., a low barrier height). The high voltage diode 13 is a high voltage and high current diode, such as a high voltage power wide band gap (WBG) transistor. In one example, the normally-on transistor 11 may have a current rating and / or a voltage rating equal to or less than that of the high voltage diode 13.
[0026] Now according to Figure 1 The connection of each terminal shown describes the configuration of transistors and diodes. The normally-on transistor 11 has a gate 11a, a drain 11b, and a source 11c. The low-voltage diode 12 has a cathode 12a and an anode 12b. The high-voltage diode 13 also has a cathode 13a and an anode 13b. The cathode 12a of the low-voltage diode 12 is connected to the source 11c of the normally-on transistor 11, and the anode 12b of the low-voltage diode 12 is connected to the gate 11a of the normally-on transistor 11. The cathode 13a of the high-voltage diode 13 is connected to the drain 11b of the normally-on transistor 11, with a node 14 between the drain 11b and the cathode 13a, and the anode 13b of the high-voltage diode 13 is connected to a node 15 between the anode 12b of the low-voltage diode 12 and the gate 11a of the normally-on transistor 11.
[0027] In one embodiment, the rated voltages of the normally-on transistor 11, the low voltage diode 12, and the high voltage diode 13 may satisfy the following relationship:
[0028] V L ≤V TR ≤V H
[0029] Where V TR represents the rated voltage of the normally-on transistor 11, V L represents the rated voltage of the low voltage diode 12, VH represents the rated voltage of the high voltage diode 13. In a non-limiting example, the rated voltage of the normally-on transistor 11 may be equal to or greater than 200V, the rated voltage of the high voltage diode 13 may be equal to or greater than 200V, and the rated voltage of the low voltage diode 12 may be equal to or less than 200V.
[0030] In one embodiment, the rated currents of the normally-on transistor 11, the low voltage diode 12, and the high voltage diode 13 may satisfy the following relationship:
[0031] I TR ≤I H
[0032] I L ≤I H
[0033] Among them I TR represents the rated current of the normally-on transistor 11, I L represents the rated current of the low voltage diode 12, I H I represents the rated current of the high voltage diode 13. TR Can be equal to, greater than, or less than I L In a non-limiting example, the rated current of the normally-on transistor 11 may be equal to or greater than 1 mA, the rated current of the low voltage diode 12 may be equal to or greater than 1 mA, and the rated current of the high voltage diode 13 may be equal to or greater than 10 mA.
[0034] Figure 2 Shows Figure 1 IV curve characteristics of the embodiment. As expected, the current remains zero in region A until the threshold voltage (V th ), the threshold voltage of the cascade diode circuit 10 according to the embodiment reaches about 0.3V, which is attributed to the combination of the normally-on transistor 11 and the low-voltage diode 12. After the threshold voltage, the current rises at a first slope in region B until the normally-on transistor 11 is fully turned on. In region C, the slope of the IV curve is a second slope. In region B, the current flows through the low-voltage diode 12; while in region C, the current flows through the high-voltage diode 13.
[0035] Due to the combination of the normally-on transistor 11 and the low-voltage diode 12, the cascade diode circuit 10 can exhibit an extremely low forward voltage (V f). Therefore, when operating at a lower current level, the cascaded diode circuit 10 can provide sufficient blocking voltage. When operating at a high current level, the high voltage diode 13 can provide sufficient current. Therefore, the cascade of the normally-on transistor 11, the low voltage diode 12, and the high voltage diode 13 provides a low-cost alternative to conventional diode circuits while maintaining excellent characteristics at current and blocking levels.
[0036] In one embodiment, the breakdown voltage of the normally-on transistor 11 is equal to or greater than the breakdown voltage of the high voltage diode 13 . In another embodiment, the breakdown voltage of the high voltage diode 13 is greater than the breakdown voltage of the low voltage diode 12 .
[0037] In yet another embodiment, an absolute value of the breakdown voltage of the low voltage diode 12 is equal to or greater than the gate threshold voltage of the normally-on transistor 11 .
[0038] See also Figure 3A , Figure 3B and Figure 4 , are the measurement results of the IV forward characteristic and reverse characteristic of the cascade diode circuit according to an embodiment of the present invention. As shown in the measurement results, the cascade diode circuit according to the embodiment can exhibit extremely low forward voltage and fast switching speed, and the combination of the normally-on transistor and the low-voltage diode provides a simple and low-cost solution.
[0039] By using a normally-on transistor with a low current / voltage rating and a combination of two diodes instead of a high voltage transistor, a cost-effective solution for a low voltage drop cascade diode circuit is provided.
[0040]
Explanation of symbols
[0041] 10: Cascade diode circuit
[0042] 11: Normally open transistor
[0043] 11a: Gate
[0044] 11b: Drain
[0045] 11c: Source
[0046] 12: Low voltage diode
[0047] 12a: cathode
[0048] 12b: Anode
[0049] 13: High voltage diode
[0050] 13a: cathode
[0051] 13b: Anode
[0052] 14: Node
[0053] 15: Node.
Claims
1. A cascade diode circuit, characterized in that: include: a normally-on transistor having a gate, a drain and a source; a low voltage diode having a cathode connected to the source of the normally-on transistor and an anode connected to the gate of the normally-on transistor; as well as a high voltage diode having a cathode connected to the drain of the normally-on transistor and an anode connected to a node between the normally-on transistor and the low voltage diode; Wherein, the rated current or rated voltage of the normally-on transistor is equal to or less than the rated current or rated voltage of the high-voltage diode.
2. The cascade diode circuit according to claim 1, characterized in that: The breakdown voltage of the normally-on transistor is equal to or greater than the breakdown voltage of the high voltage diode.
3. The cascade diode circuit according to claim 1, characterized in that: The breakdown voltage of the high voltage diode is greater than the breakdown voltage of the low voltage diode.
4. The cascade diode circuit according to claim 1, characterized in that: An absolute value of a breakdown voltage of the low voltage diode is equal to or greater than a gate threshold voltage of the normally-on transistor.
5. The cascade diode circuit according to claim 1, characterized in that: The normally-on transistor, the low-voltage diode, and the high-voltage diode satisfy the following relationship: In L ≤V TR ≤V H Among them, V TR Represents the rated voltage of the normally-on transistor, V L Indicates the rated voltage of the low voltage diode, V H Indicates the rated voltage of the high voltage diode.
6. The cascade diode circuit according to claim 1, characterized in that: The rated voltage of the normally-on transistor is equal to or greater than a predetermined value, the rated voltage of the high-voltage diode is equal to or greater than the predetermined value, and the rated voltage of the low-voltage diode is equal to or less than the predetermined value.
7. The cascade diode circuit according to claim 1, characterized in that: The rated current of the low voltage diode is equal to or less than the rated current of the high voltage diode.
8. The cascade diode circuit according to claim 1, characterized in that: The rated current of the normally-on transistor is equal to or greater than a first predetermined value, the rated current of the low-voltage diode is equal to or greater than the first predetermined value, and the rated current of the high-voltage diode is equal to or greater than a second predetermined value, wherein the second predetermined value is greater than the first predetermined value.
9. The cascade diode circuit according to claim 1, characterized in that: The rated current and rated voltage of the normally-on transistor are respectively equal to or less than the rated current and rated voltage of the high voltage diode.
10. The cascade diode circuit according to claim 1, characterized in that: The normally-on transistor is a metal oxide semiconductor field effect transistor, a junction field effect transistor or a high electron mobility transistor.