A linear voltage regulator circuit capable of detecting a load state

Abstract

The present application relates to the technical field of voltage stabilizing circuit, more particularly to a linear voltage stabilizing circuit capable of detecting load state. It comprises a DC power supply, a short-circuit protection module, an over-current protection module, a reverse voltage protection module, a wide voltage input linear voltage stabilizing module and a light load detection module for detecting load state; the wide voltage input linear voltage stabilizing module comprises a first MOS tube, a first triode, a voltage stabilizing source, a first resistor and a second resistor; the light load detection module comprises a second triode and a Schottky diode. The present application adopts the light load detection module to support the ability of detecting no-load and micro-ampere (uA) small current load; the short-circuit protection module, the over-current protection module, the reverse voltage protection module and the wide voltage input linear voltage stabilizing module are adopted to realize multiple protection functions.

Description

Technical Field

[0001] This invention relates to the technical field of voltage regulator circuits, and more specifically, to a linear voltage regulator circuit capable of detecting load conditions. Background Technology

[0002] Existing automotive linear voltage regulator chips generally support output voltage short-circuit and overcurrent protection, but do not support no-load detection or the ability to detect microampere (µA) low-current loads. During vehicle assembly, or when the current of a component is very low in a static state, employee errors could lead to the omission of a component without corresponding testing methods. This could result in a malfunctioning component, requiring rework and potentially causing a vehicle recall – a serious incident. Summary of the Invention

[0003] To overcome the problem described in the background art that the lack of corresponding detection methods when automotive parts are missing may lead to serious accidents such as vehicle recalls, this invention provides a linear voltage regulator circuit that can detect load status.

[0004] To solve the above-mentioned technical problems, the technical solution of the present invention is as follows:

[0005] This invention provides a linear voltage regulator circuit capable of detecting load conditions. The circuit includes a DC power supply, a short-circuit protection module, an overcurrent protection module, a reverse voltage protection module, a wide-input voltage linear regulator module, and a light-load detection module for detecting load conditions. The wide-input voltage linear regulator module includes a first MOSFET, a first transistor, a voltage regulator, a first resistor, and a second resistor. The light-load detection module includes a second transistor and a Schottky diode.

[0006] The positive terminal of the DC power supply is connected to the input terminals of the short-circuit protection module and the overcurrent protection module, respectively, and the negative terminal is grounded; the output terminal of the overcurrent protection module is connected to the source of the first MOSFET, and the control terminal is connected to the gate of the first MOSFET; the drain of the first MOSFET is connected to the emitter of the second transistor; the gate of the first MOSFET is also connected to the collector of the first transistor; the base of the first transistor is connected to the control terminal of the short-circuit protection module and the cathode of the voltage regulator, respectively, and the emitter is grounded; the reference terminal of the voltage regulator is provided with a voltage output terminal, and the anode is grounded; The first resistor is connected in series between the reference terminal and the voltage output terminal of the voltage regulator; the second resistor is connected in parallel between the reference terminal and the anode of the voltage regulator; the base of the second transistor is connected to the voltage output terminal, and the collector is provided with a level output detection terminal; the anode of the Schottky diode is connected to the collector of the second transistor, and the cathode is connected to the base of the second transistor; the output terminal of the short-circuit protection module is connected to the input terminal of the reverse voltage protection module, and the output terminal of the reverse voltage protection module is connected to the voltage output terminal; the input terminal of the load is connected to the base of the second transistor, and the output terminal is grounded.

[0007] Preferably, the first MOSFET is a P-channel MOSFET; the first transistor is an NPN transistor; and the second transistor is a PNP transistor.

[0008] Preferably, the overcurrent protection module includes a third transistor and a third resistor, wherein the third resistor is connected in series between the positive terminal of the DC power supply and the source terminal of the first MOSFET; the emitter of the third transistor is connected to the input terminal of the third resistor, the base is connected to the output terminal of the third resistor, and the collector is connected to the gate of the first MOSFET.

[0009] Preferably, the third transistor is a PNP transistor.

[0010] Preferably, the short-circuit module includes a second MOSFET, a fourth transistor, a fifth transistor, and a Zener diode. The base of the fourth transistor is connected to the DC power supply via a voltage divider resistor, the collector is connected to the gate of the second MOSFET, and the emitter is grounded. The positive terminal of the DC power supply is connected to the gate of the second MOSFET via a voltage divider resistor and also to the source of the second MOSFET. The drain of the second MOSFET is connected to the cathode of the Zener diode and the base of the fifth transistor. The anode of the Zener diode is grounded. The collector of the fifth transistor is connected to the base of the first transistor, and the emitter is connected to the input terminal of the reverse voltage protection module.

[0011] Preferably, the second MOSFET is a P-channel MOSFET; the fourth and fifth transistors are both NPN transistors.

[0012] Preferably, the reverse voltage protection module includes a conducting diode, the anode of which is connected to the emitter of the fifth transistor, and the cathode of which is connected to the voltage output terminal.

[0013] Preferably, the voltage regulator is a TL431 type controllable precision voltage regulator.

[0014] Preferably, the circuit further includes a first switch and a second switch, wherein the first switch is connected in parallel across the load and the second switch is connected in series with the load.

[0015] Preferably, a voltage divider resistor is connected in parallel between the emitter and base of the second diode.

[0016] Its beneficial effects are as follows:

[0017] 1. This invention employs a light-load detection module to support no-load detection and the ability to detect microampere (µA) low-current loads. By using a light-load detection module with no-load and microampere (µA) low-current load detection capabilities, the problem of missing vehicle parts is addressed, improving the accuracy and stability of vehicle part installation monitoring and reducing product defect rates during mass production.

[0018] 2. This invention employs a short-circuit protection module, an overcurrent protection module, a reverse voltage protection module, and a wide-input linear regulator module to achieve multiple protection functions. This invention implements wide-input voltage protection, output short-circuit protection, overcurrent protection, and protection against contact between the external power supply and the output voltage. Furthermore, the output voltage and current can be set by changing circuit parameters. The circuit function is optimized, and the proprietary IP is designed as an integrated circuit for wide application. Attached Figure Description

[0019] Figure 1 This is a structural block diagram of the present invention.

[0020] Figure 2 This is a circuit diagram of the present invention.

[0021] Figure 3 This is a partial circuit structure diagram of the present invention.

[0022] Figure 4 This is a circuit diagram of the light load detection module of the present invention.

[0023] Among them: DC power supply 10, overcurrent protection module 20, wide voltage input linear regulator module 30, light load detection module 40, short circuit protection module 50, and reverse voltage protection module 60.

[0024] Voltage output terminal 31, level output detection terminal 41. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. The described embodiments are some, but not all, of the embodiments of the present invention.

[0026] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0027] Example 1:

[0028] like Figure 1 As shown, the present invention provides a linear voltage regulator circuit capable of detecting load conditions. The circuit includes a DC power supply 10, a short-circuit protection module 50, an overcurrent protection module 20, a reverse voltage protection module 60, a wide voltage input linear voltage regulator module 30, and a light load detection module 40.

[0029] For details, please refer to Figure 2 The positive terminal of DC power supply 10 is connected to the input terminals of short-circuit protection module 50 and overcurrent protection module 20, respectively, while the negative terminal is grounded. DC power supply 10 is mainly used to provide voltage to the circuit.

[0030] The wide-voltage input linear regulator module 30 includes a first MOSFET Q1, a first transistor T1, a voltage regulator U1, a first resistor R1, and a second resistor R2. The light-load detection module 40 includes a second transistor T2 and a Schottky diode SD1.

[0031] The output terminal of the overcurrent protection module 20 is connected to the source of the first MOSFET Q1, and the control terminal is connected to the gate of the first MOSFET Q1. The overcurrent protection module 20 is mainly used to limit excessive current in the circuit.

[0032] In the wide-voltage input linear regulator module 30, the drain of the first MOSFET Q1 is connected to the emitter of the second transistor T2; the gate of the first MOSFET Q1 is also connected to the collector of the first transistor T1. The base of the first transistor T1 is connected to the control terminal of the short-circuit protection module 50 and the cathode of the voltage regulator U1, and the emitter is grounded; the reference terminal of the voltage regulator U1 is provided with a voltage output terminal 31, and the anode is grounded; a first resistor R1 is connected in series between the reference terminal and the voltage output terminal 31 of the voltage regulator U1; a second resistor R2 is connected in parallel between the reference terminal and the anode of the voltage regulator U1. The base of the second transistor T2 is connected to the voltage output terminal 31, and the collector is provided with a level output detection terminal 41; the anode of the Schottky diode SD1 is connected to the collector of the second transistor T2, and the cathode is connected to the base of the second transistor T2. The input terminal of the load Rb1 is connected to the base of the second transistor T2, and the output terminal is grounded. The wide-voltage input linear regulator module 30 is mainly used to stabilize the power supply voltage before outputting it. The light-load detection module 40 is mainly used to detect the state of the load Rb1.

[0033] In this embodiment, the voltage output terminal 31 is the output voltage of the external circuit. The level output detection terminal 41 is connected to the detection pin of the detection chip, and the detection chip detects the level output by the level output detection terminal 41 through the detection pin.

[0034] The output terminal of the short-circuit protection module 50 is connected to the input terminal of the reverse voltage protection module 60, and the output terminal of the reverse voltage protection module 60 is connected to the voltage output terminal 31. The short-circuit protection module 50 is mainly used to protect the circuit when it is short-circuited, preventing damage to components due to the short circuit. The reverse voltage protection module 60 is mainly used to prevent damage to the entire circuit from external power sources.

[0035] In this embodiment, the first MOSFET Q1 is a P-channel MOSFET, the first transistor T1 is an NPN transistor, and the second transistor T2 is a PNP transistor. The voltage regulator U1 is a TL431 type controllable precision voltage regulator. A voltage divider resistor is also connected in parallel between the emitter and base of the second transistor T2.

[0036] In this embodiment, the circuit further includes a first switch SW1 and a second switch SW2. The first switch SW1 is connected in parallel across the load Rb1, and the second switch SW2 is connected in series with the load Rb1. When the first switch SW1 is open and the second switch SW2 is closed, the circuit is connected to the load Rb1; when both the first switch SW1 and the second switch SW2 are open, the circuit is open-circuit; and when both the first switch SW1 and the second switch SW2 are closed, the circuit is short-circuit.

[0037] In this embodiment, the Schottky diode SD1 can carry a large current, so that as long as a small current passes through the base of the second transistor T2, the second transistor T2 will enter the conducting state, and the collector of the second transistor T2 will have current output.

[0038] With the above-described structural connections, the working principle of this embodiment is as follows: when connected to the DC power supply 10, the short-circuit protection module 50, overcurrent protection module 20, reverse voltage protection module 60, wide voltage input linear regulator module 30, and light load detection module 40 operate normally. The voltage is output as a stable voltage through the first MOSFET Q1, the first transistor T1, the voltage regulator U1, the first resistor R1, and the second resistor R2. The current flows through the first MOSFET Q1 into the light load detection module 40. The light load detection module 40, in conjunction with the detection chip, detects the state of the load Rb1. When the first switch SW1 is open and the second switch SW2 is closed, the circuit is connected to the load Rb1. The base of the second transistor T2 is pulled low, thus conducting. The detection chip outputs a voltage greater than 1V at the detection terminal 41. When both the first switch SW1 and the second switch SW2 are open, the circuit is open-circuit. The voltage between the base and emitter of the second transistor T2 is equal, so the second transistor T2 is cut off, and no current flows. The detection chip outputs a low level at the detection terminal 41. When both the first switch SW1 and the second switch SW2 are closed, the circuit is short-circuit. That is, when the load Rb1 is in a microamp (µA) low current state, a small current is introduced into the base of the second transistor T2, thus turning the second transistor T2 on. There is current output at the collector, and the detection chip outputs a voltage greater than 1V, which can be detected as a high level indicating that the load Rb1 is connected.

[0039] Example 2:

[0040] The difference between this embodiment and the first embodiment is that:

[0041] like Figure 3 As shown, the wide voltage input linear regulator module 30 in this embodiment consists of Q1, a first transistor T1, a fourth resistor R4, a fifth resistor R5, a fifteenth resistor R15, a voltage regulator U1, a first capacitor C1, a second capacitor C2, a first resistor R1, and a second resistor R2. The voltage value output by the voltage output terminal 31 can be adjusted by adjusting the resistance values ​​of the first resistor R1 and the second resistor R2.

[0042] The overcurrent protection module 20 consists of a first MOSFET Q1, a third transistor T3, a third resistor R3, and a fifth resistor R5. The current limiting point can be adjusted by adjusting the resistance value of the third resistor R3. The third transistor T3 is a PNP transistor. When the base voltage is less than the emitter voltage, the third transistor T3 enters the conducting state, and the gate and source levels of the first MOSFET Q1 are close to equal, so the first MOSFET Q1 is turned off and enters the current limiting state.

[0043] The short-circuit protection module 50 consists of a second MOSFET Q2, a fourth transistor T4, a fifth transistor T5, a ninth resistor R9, a tenth resistor R10, an eleventh resistor R11, a twelfth resistor R12, a fourteenth resistor R14, a third capacitor C3, a Zener diode Z1, and a forward diode D1. The second MOSFET Q2 is a P-channel MOSFET; the fourth transistor T4 and the fifth transistor T5 are both NPN transistors. The emitter pin of the fifth transistor T5 is used for detection. When a short circuit occurs, the cathode level of the forward diode D1 approaches 0V, causing the fifth transistor T5 to saturate and conduct, resulting in a low base level for the first transistor T1. The first transistor T1 enters the cutoff state, and the gate and source levels of the first MOSFET Q1 become equal, resulting in the first MOSFET Q1 being in the cutoff state with no voltage output, thus entering the short-circuit protection state. When the short circuit is removed, the first MOSFET Q1 returns to normal operation, and the circuit operates normally.

[0044] The reverse voltage protection module 60 includes a second transistor T2 and a conducting diode D1. The second transistor T2 and the conducting diode D1 form a reverse external power supply contact protection with the output voltage. The second transistor T2 and the conducting diode D1 are reversed relative to the output voltage of the PN junction, so the external power supply will not damage the entire circuit, thus achieving the protection effect.

[0045] like Figure 4 As shown, the light load detection module 40 consists of a second transistor T2, a sixth resistor R6, a Schottky diode SD1, a seventh resistor R7, and an eighth resistor R8. It supports open-circuit detection of load Rb1 and supports 10µs. A This circuit detects a very small current load Rb1. When the detection level output is greater than 1V, there is a load Rb1; when the detection level output is less than 0.5V, the output is short-circuited or open-circuited. When the load Rb1 is open-circuited, the voltage between the emitter and base of the second transistor T2 is equal, and T2 is in the cutoff state. No current flows through the emitter and collector of T2, and the detection terminal 41 is low. When the load Rb1 is at a microampere (µA) current, the second transistor T2 is in the conducting state, with current flowing through its base. This small current flows through T2, resulting in current output at the collector. The detection terminal 41 outputs a value greater than 1V, which is detected as a high level, indicating that the load Rb1 is connected.

[0046] Example 3:

[0047] The difference between this embodiment and Embodiment 1 or Embodiment 2 is that:

[0048] The first MOSFET Q1 is an NVF2955 MOSFET, the first transistor T1 is a BCP56-16T1 transistor, the second transistor T2 is a BCP53T1 transistor, the Schottky diode SD1 is a 1N5817 diode, and the Zener diode U1 is a TL431 controllable precision Zener diode. The third transistor T3 is a BCP56-16T1 transistor. The second MOSFET Q2 is a 2N6804 MOSFET, the fourth transistor T4 and the fifth transistor T5 are both BCP56-16T1 transistors, the Zener diode Z1 is a BZD23-C4V7 diode, and the forward diode D1 is a 1N1183 diode.

[0049] The transistors, MOSFETs, and diodes mentioned above can be replaced with transistors from different manufacturers and of different models.

[0050] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0051] In this invention, unless otherwise expressly specified and limited, "above or below" a first feature may include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on" the first feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the first feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0052] Although the description of the invention has been given in conjunction with the specific embodiments described above, it will be apparent to those skilled in the art that many substitutions, modifications, and variations can be made based on the foregoing. Therefore, all such substitutions, modifications, and variations are included within the spirit and scope of the appended claims.

Claims

1. A linear voltage regulator circuit capable of detecting load conditions, characterized in that, The circuit includes a DC power supply, a short-circuit protection module, an overcurrent protection module, a reverse voltage protection module, a wide-voltage input linear regulator module, and a light-load detection module for detecting load status; the wide-voltage input linear regulator module includes a first MOSFET, a first transistor, a voltage regulator, a first resistor, and a second resistor; the light-load detection module includes a second transistor and a Schottky diode; The positive terminal of the DC power supply is connected to the input terminals of the short-circuit protection module and the overcurrent protection module, respectively, and the negative terminal is grounded; the output terminal of the overcurrent protection module is connected to the source of the first MOSFET, and the control terminal is connected to the gate of the first MOSFET; the drain of the first MOSFET is connected to the emitter of the second transistor; the gate of the first MOSFET is also connected to the collector of the first transistor; the base of the first transistor is connected to the control terminal of the short-circuit protection module and the cathode of the voltage regulator, respectively, and the emitter is grounded; the reference terminal of the voltage regulator is provided with a voltage output terminal, and the anode is grounded; The first resistor is connected in series between the reference terminal and the voltage output terminal of the voltage regulator; the second resistor is connected in parallel between the reference terminal and the anode of the voltage regulator; the base of the second transistor is connected to the voltage output terminal, and the collector is provided with a level output detection terminal; the anode of the Schottky diode is connected to the collector of the second transistor, and the cathode is connected to the base of the second transistor; the output terminal of the short-circuit protection module is connected to the input terminal of the reverse voltage protection module, and the output terminal of the reverse voltage protection module is connected to the voltage output terminal; the input terminal of the load is connected to the base of the second transistor, and the output terminal is grounded.

2. The linear voltage regulator circuit capable of detecting load state according to claim 1, characterized in that, The first MOSFET is a P-channel MOSFET; the first transistor is an NPN transistor; and the second transistor is a PNP transistor.

3. The linear voltage regulator circuit capable of detecting load state according to claim 1, characterized in that, The overcurrent protection module includes a third transistor and a third resistor. The third resistor is connected in series between the positive terminal of the DC power supply and the source terminal of the first MOSFET. The emitter of the third transistor is connected to the input terminal of the third resistor, the base is connected to the output terminal of the third resistor, and the collector is connected to the gate of the first MOSFET.

4. The linear voltage regulator circuit capable of detecting load state according to claim 3, characterized in that, The third transistor is a PNP transistor.

5. The linear voltage regulator circuit capable of detecting load state according to claim 1, characterized in that, The short-circuit protection module includes a second MOSFET, a fourth transistor, a fifth transistor, and a Zener diode. The base of the fourth transistor is connected to the DC power supply via a voltage divider resistor, the collector is connected to the gate of the second MOSFET, and the emitter is grounded. The positive terminal of the DC power supply is connected to the gate of the second MOSFET via a voltage divider resistor and also to the source of the second MOSFET. The drain of the second MOSFET is connected to the cathode of the Zener diode and the base of the fifth transistor. The anode of the Zener diode is grounded. The collector of the fifth transistor is connected to the base of the first transistor, and the emitter is connected to the input terminal of the reverse voltage protection module.

6. The linear voltage regulator circuit capable of detecting load state according to claim 5, characterized in that, The second MOSFET is a P-channel MOSFET; the fourth and fifth transistors are both NPN transistors.

7. The linear voltage regulator circuit capable of detecting load state according to claim 5, characterized in that, The reverse voltage protection module includes a conducting diode, the anode of which is connected to the emitter of the fifth transistor, and the cathode of which is connected to the voltage output terminal.

8. The linear voltage regulator circuit capable of detecting load state according to claim 1, characterized in that, The voltage regulator is a TL431 model controllable precision voltage regulator.

9. The linear voltage regulator circuit capable of detecting load state according to claim 1, characterized in that, The circuit also includes a first switch and a second switch, the first switch being connected in parallel across the load and the second switch being connected in series with the load.

10. The linear voltage regulator circuit capable of detecting load state according to claim 1, characterized in that, A voltage divider resistor is also connected in parallel between the emitter and base of the second transistor.

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