High-side short-circuit protection circuit based on discrete component

Abstract

The utility model provides a discrete component-based high-side short-circuit protection circuit, which comprises a high-side conduction module connected with an enable signal and a short-circuit protection module connected to the output end of the high-side conduction module, and the output end of the short-circuit protection module is connected with electric equipment. A short circuit detection module is connected between the output end and the feedback input end of the short circuit protection module. According to the high-side short-circuit protection circuit based on the discrete component, the short-circuit detection module detects the output short-circuit condition and feeds back the detection condition to the short-circuit protection module, and when short circuit occurs, the short-circuit protection module disconnects the connection between the high side and the electric equipment, so that the circuit is automatically closed when the output short circuit occurs, and the safety of the circuit is improved. The defect that the circuit cannot automatically close the output after the traditional circuit is short-circuited to the ground is overcome.

Description

Technical Field

[0001] The utility model relates to the field of circuits, and particularly to a high-side short-circuit protection circuit based on discrete components. Background Art

[0002] Currently, the protection principle of the high-side short-circuit protection circuit composed of discrete components is mostly realized by the current-limiting resistor on the output path, as shown in Figure 1 . However, after the ground short circuit occurs, the circuit cannot turn off the output by itself and still maintains the state of the ground short circuit. The circuit continuously outputs a large short-circuit current, and the continuous heating of the circuit easily leads to a sharp increase in power consumption and even damage to the device; moreover, although the current-limiting resistor on the output path can limit the output current in the short-circuit state, it will also reduce the output current during the normal operation of the circuit, thereby reducing the output power. Therefore, it is not suitable for high-power scenarios. Summary of the Utility Model

[0003] In order to overcome the defects existing in the above-mentioned prior art, the purpose of the utility model is to provide a high-side short-circuit protection circuit based on discrete components.

[0004] In order to achieve the above object of the utility model, the utility model provides a high-side short-circuit protection circuit based on discrete components, which includes a high-side conduction module connected to an enable signal and a short-circuit protection module connected to the voltage output end of the high-side conduction module. The output end of the short-circuit protection module is connected to an electrical device, and a short-circuit detection module is connected between the output end and the feedback input end of the short-circuit protection module.

[0005] The high-side short-circuit protection circuit based on discrete components detects the output short-circuit situation through the short-circuit detection module and feeds the detection situation back to the short-circuit protection module. When a short circuit occurs, the short-circuit protection module disconnects the connection between the high side and the electrical device.

[0006] In an optional scheme of the high-side short-circuit protection circuit based on discrete components, the short-circuit protection module includes a PMOS transistor and an NMOS transistor;

[0007] The source electrode of the PMOS transistor is connected to the voltage output end of the high-side conduction module, the drain electrode of the PMOS transistor is connected to the electrical device, and its gate electrode is grounded after being connected in series with a capacitor; the gate electrode of the PMOS transistor is also connected to the voltage output end of the high-side conduction module together with the drain electrode of the NMOS transistor; the source electrode of the NMOS transistor is grounded, and the short-circuit detection module is connected between its gate electrode and the drain electrode of the PMOS transistor.

[0008] In an optional scheme of the high-side short-circuit protection circuit based on discrete components, the short-circuit detection module includes a detection resistor connected in series between the drain electrode of the PMOS transistor and the gate electrode of the NMOS transistor.

[0009] In an alternative solution of the high-side short-circuit protection circuit based on discrete components, the high-side conduction module includes an NPN transistor with its base connected to the control enable terminal. The emitter of the NPN transistor is grounded, and its collector is connected to the base of a PNP transistor. The emitter of the PNP transistor is connected to VCC, and its collector is connected to the short-circuit protection module.

[0010] In an alternative solution of the high-side short-circuit protection circuit based on discrete components, the detection resistor is further connected to a voltage-dividing resistor, and the voltage-dividing resistor is grounded.

[0011] In an alternative solution of the high-side short-circuit protection circuit based on discrete components, the model of the PMOS transistor is YJD18GP10A, and the model of the NMOS transistor is NCE6005AR.

[0012] In an alternative solution of the high-side short-circuit protection circuit based on discrete components, the model of the NPN transistor is LMBT5551 LT1 G, and the model of the PNP transistor is the Darlington transistor MJD127.

[0013] The beneficial effects of the present utility model are as follows: The present utility model realizes that the circuit automatically shuts down when the output is short-circuited, overcoming the drawback that the traditional circuit cannot automatically shut down the output after a ground short-circuit occurs. Since the on-resistance of the PMOS transistor on the output path is in the mΩ level, which is much smaller than the resistance value of the current-limiting resistor on the output path of the traditional circuit, this greatly increases the output power of the circuit and overcomes the drawback of the small output power of the traditional circuit.

[0014] The additional aspects and advantages of the present utility model will be partially given in the following description, partially will become obvious from the following description, or will be understood through the practice of the present utility model. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The above and / or additional aspects and advantages of the present utility model will become obvious and easy to understand from the description of the embodiments in conjunction with the following drawings, wherein:

[0016] Figure 1 is a schematic diagram of the circuit principle of the prior art;

[0017] Figure 2 is a block diagram of the principle of the embodiment;

[0018] Figure 3 is a schematic diagram of the circuit principle of the embodiment. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0019] Embodiments of the present utility model will be described in detail below. Examples of the embodiments are shown in the accompanying drawings, where the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by referring to the accompanying drawings are exemplary and are only used to explain the present utility model and should not be construed as a limitation of the present utility model.

[0020] In the description of the present utility model, unless otherwise specified and defined, it should be noted that the terms "installation", "connection", and "connection" should be understood in a broad sense. For example, it can be a mechanical connection or an electrical connection, or it can be the communication inside two elements. It can be directly connected or indirectly connected through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms can be understood according to specific circumstances.

[0021] As Figure 2 and Figure 3 shown, the present application provides an embodiment of a high-side short-circuit protection circuit based on discrete components. The protection circuit in this embodiment includes a high-side conduction module connected to an enable signal and a short-circuit protection module connected to the voltage output terminal of the high-side conduction module. The output terminal of the short-circuit protection module is connected to an electrical device, and a short-circuit detection module is connected between the output terminal and the feedback input terminal of the short-circuit protection module. The short-circuit detection module detects the output short-circuit situation and feeds back the detection situation to the short-circuit protection module. When a short circuit occurs, the short-circuit protection module disconnects the connection between the high side and the electrical device.

[0022] In this embodiment, the high-side conduction module includes an NPN transistor Q31 and a PNP transistor Q36. The control enable terminal EN is connected to the positive electrode of the first diode D42. The negative electrode of the first diode D42 is connected to one end of the first resistor R65. The other end of the first resistor R65 is respectively connected to the base of the NPN transistor Q31 and one end of the second resistor R94. The second resistor R94 is grounded. The emitter of the NPN transistor Q31 is grounded, and its collector is connected to one end of the third resistor R49. The other end of the third resistor R49 is connected to the base of the PNP transistor. The other end of the third resistor R49 is also connected to one end of the fourth resistor R47. The other end of the fourth resistor R47 is connected to VCC. The emitter of the PNP transistor Q36 is connected to VCC, and its collector is connected to the short-circuit protection module. The collector of the PNP transistor Q36 is the voltage output terminal of the high-side conduction module.

[0023] The short - circuit protection module includes PMOS transistor Q8 and NMOS transistor Q39. In the high - side conduction module, the collector of PNP transistor Q36 is connected to the source of PMOS transistor Q8. The drain of this PMOS transistor Q8 is connected to the positive electrode of the second diode D26. The negative electrode of the second diode D26 is connected to the electrical device. The negative electrode of the second diode D26 is also connected to one end of the first capacitor C43, and the other end of the first capacitor C43 is grounded. The gate of PMOS transistor Q8 is connected to one end of the fifth resistor R20. The other end of the fifth resistor R20 is connected to one end of the second capacitor C140, and the other end of the second capacitor C140 is grounded; the other end of the fifth resistor R20 is connected to one end of the sixth resistor R59. The drain of NMOS transistor Q39 is also connected to this end of the sixth resistor R59. The other end of the sixth resistor R59 is connected to the voltage output terminal of the high - side conduction module, that is, the collector of PNP transistor Q36. The source of NMOS transistor Q39 is grounded, and a short - circuit detection module is connected between its gate and the drain of PMOS transistor Q8. In this embodiment, the short - circuit detection module includes a detection resistor R203, and this detection resistor R203 is connected in series between the drain of PMOS transistor Q8 and the gate of NMOS transistor Q39. The detection resistor R203 is also connected to a voltage - dividing resistor R204, and this voltage - dividing resistor R204 is grounded.

[0024] In this embodiment, VCC is 24V. The NPN transistor Q31 is preferably but not limited to a transistor of model LMBT5551 LT1 G. The PNP transistor Q36 is preferably but not limited to a Darlington transistor of model MJD127. The PMOS transistor Q8 is preferably but not limited to a MOS transistor of model YJD18GP10A. The NMOS transistor Q39 is preferably but not limited to a MOS transistor of model NCE6005AR.

[0025] Working principle: When the control enable terminal EN outputs a high level, the NPN transistor Q31 conducts, and the PNP transistor Q36 conducts. The source of PMOS transistor Q8 is at 24V voltage. At this time, at the collector of PNP transistor Q36, that is, Figure 1 at the network VCC_24V_1 in Figure 3 is also 24V. Due to the existence of the second capacitor C140 Figure 3 the voltage at point A in Figure 3 cannot change suddenly and remains at 0V state at the moment of turn - on. Therefore, the PMOS transistor Q8 conducts, Figure 3 and 24V is output at point B in

[0026] When the output terminal OUT is shorted to GND, Figure 3 the voltages at points B and C in Figure 3 are pulled to the GND voltage, so that the gate of NMOS transistor Q39 becomes a low potential, less than the turn-on voltage of NMOS transistor Q39, and NMOS transistor Q39 is turned off. Figure 3 The voltage at point A in Figure 3 changes from 0V during normal output to the voltage after charging the second capacitor C140 through the sixth resistor R59. After the second capacitor C140 is fully charged, the voltage at point A is the voltage of the network VCC_24V_1, which is 24V. Therefore, PMOS transistor Q8 is turned off, and the output of the output terminal OUT is turned off. Thus, when the output is short-circuited, the circuit shuts down automatically, overcoming the drawback that the traditional circuit cannot shut down the output automatically after a ground short-circuit occurs. Since the on-resistance of PMOS transistor Q8 in the output path is in the mΩ level, which is much smaller than the resistance value of the current-limiting resistor in the output path of the traditional circuit, this will greatly increase the output power of the circuit, overcoming the drawback of the small output power of the traditional circuit. During specific implementation, the short-circuit protection time can be modified by changing the capacitance value of the second capacitor C140.

[0027] In the description of this specification, the descriptions referring to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples", etc. mean that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0028] Although the embodiments of the present invention have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention, and the scope of the present invention is defined by the claims and their equivalents.

Claims

1. A high-side short-circuit protection circuit based on discrete components, characterized in that: It includes a high-side conduction module connected to an enable signal and a short-circuit protection module connected to a voltage output end of the high-side conduction module. The output end of the short-circuit protection module is connected to an electrical device. A short-circuit detection module is connected between the output end and the feedback input end of the short-circuit protection module.

2. The high-side short-circuit protection circuit based on discrete components according to claim 1, characterized in that: The short circuit protection module includes a PMOS tube and an NMOS tube; The source of the PMOS tube is connected to the voltage output end of the high-side conduction module, the drain of the PMOS tube is connected to the electrical equipment, and the gate thereof is connected in series with a capacitor and then grounded; the gate of the PMOS tube is also connected to the voltage output end of the high-side conduction module together with the drain of the NMOS tube; the source of the NMOS tube is grounded, and the short-circuit detection module is connected between the gate thereof and the drain of the PMOS tube.

3. The high-side short-circuit protection circuit based on discrete components according to claim 2, characterized in that: The short circuit detection module includes a detection resistor connected in series between the drain of the PMOS tube and the gate of the NMOS tube.

4. The high-side short-circuit protection circuit based on discrete components according to claim 1, characterized in that: The high-side conduction module includes an NPN transistor whose base is connected to the control enable terminal, whose emitter is grounded, whose collector is connected to the base of the PNP transistor, whose emitter is connected to VCC, and whose collector is connected to the short-circuit protection module.

5. The high-side short-circuit protection circuit based on discrete components according to claim 3, characterized in that: The detection resistor is also connected to a voltage-dividing resistor, and the voltage-dividing resistor is grounded.

6. The high-side short-circuit protection circuit based on discrete components according to claim 2, characterized in that: The PMOS tube model is YJD18GP10A, and the NMOS tube model is NCE6005AR.

7. The high-side short-circuit protection circuit based on discrete components according to claim 4, characterized in that: The NPN transistor model is LMBT5551LT1G, and the PNP transistor model is Darlington transistor MJD127.

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