TBU circuit

Abstract

The utility model discloses a TBU circuit, which comprises an N-channel depletion type MOSFET or an N-channel JFET, a P-channel depletion type MOSFET and a current limiting element, the source electrode of the N-channel depletion type MOSFET or the N-channel JFET is connected with the source electrode of the P-channel depletion type MOSFET, one end of the current limiting element is connected with the grid electrode of the N-channel depletion type MOSFET or the N-channel JFET, and the other end of the current limiting element is connected with the drain electrode of the P-channel depletion type MOSFET; a first voltage stabilizing branch is connected in parallel between the grid electrode and the source electrode of the N-channel depletion type MOSFET or the N-channel JFET, and a second voltage stabilizing branch is connected in parallel between the source electrode and the grid electrode of the P-channel depletion type MOSFET. According to the utility model, the voltage proportion of the N-channel depletion type MOSFET or the N-channel JFET and the P-channel depletion type MOSFET can be adjusted, and the withstand voltage value of the N-channel depletion type MOSFET or the N-channel JFET and the P-channel depletion type MOSFET can be designed flexibly.

Description

Technical Field

[0001] The utility model relates to the field of electronic technology, in particular to a TBU circuit. Background Art

[0002] TBU: Abbreviation of Transient Blocking Units, that is, transient blocking unit, or also called transient surge current suppression, a high-speed circuit protection device made of MOSFET (metal oxide semiconductor field effect transistor or junction field effect transistor) semiconductor technology. It can be simply understood as an upgraded version of PTC (self-resetting fuse). It is often used in cooperation with electronic components such as TVS tubes and GDT tubes to protect sensitive electronic circuits from the interference and damage of surge voltages and currents caused by NEMP, LEMP, etc.

[0003] The patent application with the application number 202321364732.X discloses a TBU circuit, which uses a P-channel depletion MOSFET and can not only block the surge current but also suppress the high-voltage pulse interference (without the need to add additional devices), and has the dual protection functions of overcurrent and overvoltage.

[0004] After the above TBU circuit selects the current-limiting element, the first voltage-regulating element, and the second voltage-regulating element, the voltage drop on the N-channel depletion MOSFET or N-channel JFET, P-channel depletion MOSFET is determined, and the voltage ratio on the N-channel depletion MOSFET or N-channel JFET, P-channel depletion MOSFET cannot be adjusted anymore, resulting in a lack of flexibility when designing the breakdown voltage value of the N-channel depletion MOSFET or N-channel JFET, P-channel depletion MOSFET. Summary of the Utility Model

[0005] To overcome the above defects, the utility model aims to provide a TBU circuit, which adds a voltage-dividing resistor, can adjust the voltage ratio on the N-channel depletion MOSFET or N-channel JFET, P-channel depletion MOSFET, and can design the breakdown voltage value of the N-channel depletion MOSFET or N-channel JFET, P-channel depletion MOSFET more flexibly.

[0006] To achieve the above purpose, the technical solution adopted by the utility model is as follows:

[0007] A TBU circuit includes an N-channel depletion MOSFET or an N-channel JFET, a P-channel depletion MOSFET, and a current-limiting element. The source of the N-channel depletion MOSFET or the N-channel JFET is connected to the source of the P-channel depletion MOSFET. One end of the current-limiting element is connected to the gate of the N-channel depletion MOSFET or the N-channel JFET, and the other end of the current-limiting element is connected to the drain of the P-channel depletion MOSFET;

[0008] A first voltage stabilizing branch is connected in parallel between the gate and the source of the N-channel depletion MOSFET or the N-channel JFET, and a second voltage stabilizing branch is connected in parallel between the source and the gate of the P-channel depletion MOSFET;

[0009] The drain of the N-channel depletion MOSFET or the N-channel JFET is connected to the gate of the P-channel depletion MOSFET through a voltage-dividing resistor.

[0010] Preferably, both the first voltage stabilizing branch and the second voltage stabilizing branch include two zener diodes connected in reverse series.

[0011] Further preferably, the anodes of the two zener diodes in the first voltage stabilizing branch are connected to each other. The cathode of one zener diode is connected to the gate of the N-channel depletion MOSFET or the N-channel JFET, and the cathode of the other zener diode is connected to the source of the N-channel depletion MOSFET or the N-channel JFET;

[0012] The anodes of the two zener diodes in the second voltage stabilizing branch are connected to each other. The cathode of one zener diode is connected to the gate of the P-channel depletion MOSFET, and the cathode of the other zener diode is connected to the source of the P-channel depletion MOSFET.

[0013] Preferably, the breakdown voltage of the zener diode in the first voltage stabilizing branch is greater than the threshold voltage of the N-channel depletion MOSFET or the N-channel JFET, and the breakdown voltage of the zener diode in the second voltage stabilizing branch is greater than the threshold voltage of the P-channel depletion MOSFET.

[0014] Preferably, the breakdown voltage of the zener diode is 10V.

[0015] Preferably, the current-limiting element is a current-limiting resistor, and the current-limiting resistor is a polysilicon resistor or a well resistor.

[0016] Preferably, the breakdown voltage of the P-channel depletion MOSFET is greater than the breakdown voltage of the N-channel depletion MOSFET or the N-channel JFET.

[0017] Further preferably, the breakdown voltage of the P-channel depletion MOSFET is not less than 400V.

[0018] Preferably, when in use, the TBU circuit is connected in series in the circuit to be protected through the drain of the N-channel depletion MOSFET or N-channel JFET and the drain of the P-channel depletion MOSFET. The drain of the N-channel depletion MOSFET or N-channel JFET is the current inflow end; the drain of the P-channel depletion MOSFET is the current outflow end.

[0019] Furthermore, the TBU circuit is integrally packaged into a two-terminal device. The drain of the N-channel depletion MOSFET or N-channel JFET is one end of the two-terminal device, and the drain of the P-channel depletion MOSFET is the other end of the two-terminal device.

[0020] Compared with the patent application with the application number 202321364732.X, on the basis of being able to suppress high-voltage pulse interference and having the dual protection functions of overcurrent and overvoltage, the present utility model has the following technical effects:

[0021] 1. Between the drain of the N-channel depletion MOSFET or N-channel JFET and the gate of the P-channel depletion MOSFET of the present utility model, a voltage-dividing resistor is added. By changing the resistance value of the voltage-dividing resistor, the voltage division of the current-limiting element, the first voltage-stabilizing branch, the second voltage-stabilizing branch, and the voltage-dividing resistor can be adjusted, so as to realize the adjustment of the voltage ratio between the drain-source ends of the N-channel depletion MOSFET or N-channel JFET and the drain-source ends of the P-channel depletion MOSFET. In this way, in the design of component parameters, the breakdown voltage values of the N-channel depletion MOSFET or N-channel JFET and the P-channel depletion MOSFET can be designed more flexibly. For example, either the N-channel depletion MOSFET or N-channel JFET can bear high voltage, or the P-channel depletion MOSFET can bear high voltage, making the module design easier.

[0022] 2. The present utility model can adjust the trigger voltage magnitude for the module (i.e., the TBU circuit) to switch from the low-resistance conduction state to the off state by changing the resistance value of the voltage-dividing resistor. For example, increasing the resistance value of the voltage-dividing resistor can increase the trigger voltage of the module, thereby reducing the misoperation of the module caused by slight fluctuations in external signals. And it is beneficial for the module to quickly switch from the off state to the conduction state.

[0023] 3. The present utility model can effectively adjust the power distribution relationship between the internal components of the module, which is beneficial to balancing the voltage distribution of the N-channel depletion MOSFET or N-channel JFET and the P-channel depletion MOSFET, optimizing the design scheme, so as to reduce the on-resistance of the circuit module, reduce power loss, and increase the stability and reliability of the module.

[0024] 4. The two back-to-back connected zener diodes added in the present utility model can ensure that when an overvoltage signal is input from the input end of the module, the P-channel depletion MOSFET can respond quickly, and the whole module switches from the low-resistance conduction state to the off state. Description of the Drawings

[0025] Figure 1 It is the circuit schematic diagram of Embodiment 1.

[0026] Figure 2 It is the circuit schematic diagram of Embodiment 2. Detailed Implementation Manner

[0027] In order to make the purpose, technical solutions and advantages of the present utility model clearer, the present utility model will be further described in detail below with reference to the drawings.

[0028] Embodiment 1

[0029] This embodiment discloses a TBU circuit, specifically as Figure 1 shown, including an N-channel depletion MOSFET Q1, a P-channel depletion MOSFET Q2 and a current-limiting element. In this embodiment, the current-limiting element is a current-limiting resistor R1. The source of the N-channel depletion MOSFET Q1 is connected to the source of the P-channel depletion MOSFET Q2. One end of the current-limiting resistor R1 is connected to the gate of the N-channel depletion MOSFET Q1, and the other end of the current-limiting resistor R1 is connected to the drain of the P-channel depletion MOSFET Q2. A first voltage-stabilizing branch is connected in parallel between the gate and the source of the N-channel depletion MOSFET Q1, and a second voltage-stabilizing branch is connected in parallel between the source and the gate of the P-channel depletion MOSFET Q2. In this embodiment, the first voltage-stabilizing branch includes a zener diode D1. The anode of the zener diode D1 is connected to the gate of the N-channel depletion MOSFET Q1, and the cathode of the zener diode D1 is connected to the source of the N-channel depletion MOSFET Q1. The second voltage-stabilizing branch includes a zener diode D3. The anode of the zener diode D3 is connected to the source of the P-channel depletion MOSFET Q2, and the cathode of the zener diode D3 is connected to the gate of the P-channel depletion MOSFET Q2. The drain of the N-channel depletion MOSFET Q1 is connected to the gate of the P-channel depletion MOSFET Q2 through a voltage-dividing resistor R2.

[0030] Among them, the N-channel depletion MOSFET Q1 can be replaced by an N-channel JFET; the current-limiting resistor R1 is a polysilicon resistor or a well resistor; the breakdown voltage of the P-channel depletion MOSFET Q2 is greater than that of the N-channel depletion MOSFET Q1 or the N-channel JFET.

[0031] To meet the high-voltage requirement, the breakdown voltage of the P-channel depletion MOSFET Q2 is not less than 400V.

[0032] When this embodiment is in use, the drain of the N-channel depletion MOSFET Q1 or the N-channel JFET and the drain of the P-channel depletion MOSFET Q2 are connected in series in the protected circuit. The drain of the N-channel depletion MOSFET Q1 or the N-channel JFET is the current input end; the drain of the P-channel depletion MOSFET Q2 is the current output end.

[0033] In this embodiment, this TBU circuit can be integrally packaged into a two-terminal device. The drain of the N-channel depletion MOSFET Q1 or the N-channel JFET is one end of the two-terminal device, that is, the module input end; the drain of the P-channel depletion MOSFET Q2 is the other end of the two-terminal device, that is, the module output end.

[0034] Based on the patent application with the application number 202321364732.X, this embodiment adds a voltage-dividing resistor R2. By changing the resistance value of the voltage-dividing resistor R2, the voltage division of the current-limiting element R1, the voltage-regulating diode D1, the voltage-regulating diode D3, and the voltage-dividing resistor R2 can be adjusted, so as to realize the adjustment of the voltage ratio between the drain of the N-channel depletion MOSFET Q1 or the N-channel JFET and the drain-source ends of the P-channel depletion MOSFET Q2.

[0035] Embodiment 2

[0036] As Figure 2 shown, on the basis of Embodiment 1, this embodiment adds a voltage-regulating diode D2 connected in reverse series with the voltage-regulating diode D1, and a voltage-regulating diode D4 connected in reverse series with the voltage-regulating diode D3.

[0037] The voltage-regulating diode D1, the voltage-regulating diode D2, the voltage-regulating diode D3, and the voltage-regulating diode D4 can be designed using the same parameter process, and the breakdown voltage should exceed the threshold voltage value of Q1 or Q2. It is usually recommended to design the breakdown voltage to be about 10V.

[0038] This embodiment can adjust the voltage division of the current-limiting element R1, the voltage-regulating diode D1, the voltage-regulating diode D2, the voltage-regulating diode D3, the voltage-regulating diode D4, and the voltage-dividing resistor R2 by changing the resistance value of the voltage-dividing resistor R2, so as to realize the adjustment of the voltage ratio between the drain-source ends of the N-channel depletion MOSFET or the N-channel JFET Q1 and the drain-source ends of the P-channel depletion MOSFET Q2.

[0039] This embodiment adds two voltage-regulating diodes connected in reverse series, which can ensure that when an overvoltage signal is input from the module input end, the P-channel depletion MOSFET Q2 can respond quickly, and the whole module switches from the low-resistance conduction state to the off state.

[0040] Other parts of this embodiment are the same as those of Embodiment 1, so they will not be elaborated here.

[0041] In summary, after adding two voltage stabilizing diodes and a voltage dividing resistor R2 in this embodiment, this embodiment can still achieve the circuit functions of the original circuit of the patent application 202321364732.X. Moreover, in this embodiment, the voltage distribution among the internal components of the module can be balanced by changing the resistance value of R2, so that the withstand voltage design values of the N-channel depletion-type MOSFET Q1 and the P-channel depletion-type MOSFET Q2 can be flexibly matched, and the power distribution relationship among the internal components of the module can be optimized.

[0042] This embodiment can also adjust the trigger voltage of the module, reduce the misoperation of the module, enable the module to recover quickly, and enhance the stability and reliability of the module.

[0043] Certainly, there can be many other embodiments of the present utility model. Without departing from the spirit and essence of the present utility model, those skilled in the art can make various corresponding changes and deformations according to the present utility model, but these corresponding changes and deformations should all fall within the protection scope of the appended claims of the present utility model.

Claims

1. A TBU circuit includes an N-channel depletion MOSFET or an N-channel JFET, a P-channel depletion MOSFET, and a current-limiting element. The source of the N-channel depletion MOSFET or the N-channel JFET is connected to the source of the P-channel depletion MOSFET. One end of the current-limiting element is connected to the gate of the N-channel depletion MOSFET or the N-channel JFET, and the other end of the current-limiting element is connected to the drain of the P-channel depletion MOSFET; A first voltage-stabilizing branch is connected in parallel between the gate and the source of the N-channel depletion MOSFET or the N-channel JFET, and a second voltage-stabilizing branch is connected in parallel between the source and the gate of the P-channel depletion MOSFET; It is characterized in that: The drain of the N-channel depletion MOSFET or the N-channel JFET is connected to the gate of the P-channel depletion MOSFET through a voltage-dividing resistor.

2. The TBU circuit according to claim 1, wherein: Both the first voltage-stabilizing branch and the second voltage-stabilizing branch include two zener diodes connected in reverse series.

3. A TBU circuit according to claim 2, characterized in that: The anodes of the two zener diodes in the first voltage-stabilizing branch are connected to each other. The cathode of one zener diode is connected to the gate of the N-channel depletion MOSFET or the N-channel JFET, and the cathode of the other zener diode is connected to the source of the N-channel depletion MOSFET or the N-channel JFET; The anodes of the two zener diodes in the second voltage-stabilizing branch are connected to each other. The cathode of one zener diode is connected to the gate of the P-channel depletion MOSFET, and the cathode of the other zener diode is connected to the source of the P-channel depletion MOSFET.

4. A TBU circuit according to claim 3, characterized in that: The breakdown voltage of the zener diode in the first voltage-stabilizing branch is greater than the threshold voltage of the N-channel depletion MOSFET or the N-channel JFET, and the breakdown voltage of the zener diode in the second voltage-stabilizing branch is greater than the threshold voltage of the P-channel depletion MOSFET.

5. A TBU circuit according to claim 4, characterized in that: The breakdown voltage of the zener diode is 10V.

6. A TBU circuit according to claim 1, wherein: The current-limiting element is a current-limiting resistor, and the current-limiting resistor is a polysilicon resistor or a well resistor.

7. A TBU circuit according to claim 1, characterized in that: The breakdown voltage of the P-channel depletion MOSFET is greater than that of the N-channel depletion MOSFET or the N-channel JFET.

8. A TBU circuit according to claim 6, characterized in that: The breakdown voltage of the P-channel depletion MOSFET is not less than 400V.

9. A TBU circuit according to any one of claims 1-8, characterized in that: When in use, the TBU circuit is connected in series in the protected circuit through the drain of the N-channel depletion MOSFET or the N-channel JFET and the drain of the P-channel depletion MOSFET. The drain of the N-channel depletion MOSFET or the N-channel JFET is the current input end; the drain of the P-channel depletion MOSFET is the current output end.

10. A TBU circuit according to claim 9, characterized in that: The TBU circuit is integrally packaged into a two-terminal device. The drain of the N-channel depletion MOSFET or the N-channel JFET is one end of the two-terminal device, and the drain of the P-channel depletion MOSFET is the other end of the two-terminal device.

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