A circuit for integrated speed regulation fan and abnormal state detection

Abstract

The present application belongs to the technical field of integrated circuits, and particularly relates to a circuit for integrated speed-regulating fan and abnormal state detection. The application relates to a circuit for integrated speed-regulating fan and abnormal state detection, which comprises: a current-expanding driving module, which provides a voltage FCC for the fan after LDO voltage stabilization, and expands the output current of the LDO to drive the fan; a logic control module connected with the current-expanding driving module, which adjusts a control signal ADJ <n:0>The value of the voltage FCC output by the LDO is changed to regulate the fan; the sampling detection module is connected with the logic control module and the fan, samples the current of the fan through a sampling resistor and converts the current into a voltage V0, compares the voltage V0 with a reference voltage Vref and outputs a voltage signal to a level shift circuit. The application integrates the fan driving circuit with adjustable speed and realizes the detection of various abnormal states of the fan, has the outstanding advantages of simple PCB layout and low cost.< / n:0>

Description

Technical Field

[0001] This invention belongs to the field of integrated circuit technology, and specifically relates to a circuit that integrates a speed-regulating fan and abnormal state detection. Background Technology

[0002] With the increasing integration of electronic circuits, heat dissipation has become a crucial issue for power electronic products. Especially when circuits operate at high power and high voltage, the heat generated during prolonged operation is significant. If heat dissipation is not timely, prolonged operation will lead to increased device temperature, potentially affecting device lifespan or even damaging the device. Therefore, the problem of device heat dissipation is becoming increasingly prominent.

[0003] To effectively overcome the heat dissipation challenges of equipment circuits, fans, as an efficient heat dissipation method, are widely used in the integrated circuit field. Currently, there are various fan operation status detection technologies on the market, a typical method being through monitoring the fan motor status. For example, a fan detection circuit with patent publication number CN101113992A includes an overcurrent protection device, a clamping circuit, a voltage divider circuit, and an electronic switch. The overcurrent protection device is connected to the fan power supply and the first terminal of the fan interface, respectively; the clamping circuit consists of diodes D1 and D2, and the voltage divider circuit consists of resistors R2 and R3. The clamping circuit and the voltage divider circuit are connected between the second terminal of the fan interface and ground; the control terminal of the electronic switch T1 is connected to the middle terminal of the voltage divider circuit. The circuit detects the fan status by detecting the fan power supply current; it uses the clamping voltage of the diode during forward conduction to determine whether the fan is in position and whether there is a short circuit or short circuit fault; and it uses the turn-on characteristics of a bipolar transistor to convert the fan operating status into a digital quantity for use by the monitoring system.

[0004] However, existing fan detection methods are mostly implemented through discrete component designs, which occupy a large area of ​​PCB board and have high costs. In addition, using a single fan detection method, the fan speed cannot be adjusted and multiple abnormal states cannot be detected. Summary of the Invention

[0005] The purpose of this invention is to provide a circuit that integrates speed-adjustable fan and abnormal state detection. Compared with single fan detection or direct-drive fan solutions, this invention integrates an adjustable fan drive circuit and realizes the detection of various fan abnormal states, and has the outstanding advantages of simple PCB layout and low cost.

[0006] To solve the above-mentioned technical problems, the present invention provides a circuit integrating a speed-regulating fan and abnormal state detection, comprising:

[0007] The current amplification drive module provides the fan with a voltage FCC regulated by the LDO, and amplifies the output current of the LDO to drive the fan;

[0008] The logic control module is connected to the current amplification drive module and adjusts the control signal ADJ. <n:0>The fan speed is adjusted by changing the value of the LDO output voltage FCC.

[0009] The sampling and detection module is connected to the fan and to the logic control module via the SEN port. It samples the current of the fan through a sampling resistor and converts it into a voltage V0. After comparing the voltage V0 with the reference voltage Vref, it outputs a voltage signal to the level shifting circuit. The level shifting circuit shifts the voltage signal and outputs a status flag FTO to the logic control module. Based on the waveform and level of the status flag FTO, the abnormal state of the fan is determined.

[0010] Preferably, the current amplification drive module includes: a transistor Q1, a resistor R0, and an LDO; the emitter of the transistor Q1 and one end of the resistor R0 are connected to the operating power supply VCC, the base of the transistor Q1 is connected to the other end of the resistor R0 and the VIN port of the LDO, and the collector of the transistor Q1 is connected to the output terminal of the LDO and the fan.

[0011] Preferably, it also includes a resistor R1, which is connected between the base of the transistor Q1 and the other end of the resistor R0.

[0012] Preferably, it also includes an EN port and an ADJ port, and the LDO is connected to the logic control module through the EN port and the ADJ port respectively.

[0013] Preferably, the sampling and detection module includes: resistor R0', resistors R12~R13, resistors R15~R16, comparator CMP, transistor N1, and level shifting circuit; one end of resistor R0' is connected to the fan and the non-inverting input of comparator CMP, and the other end is grounded; the inverting input of comparator CMP is connected to one end of resistor R15 and resistor R16 (which functions as a voltage divider), one end of resistor R16 is connected to the operating power supply VDD, and the other end is grounded; the other end of resistor R15 is connected to the collector of transistor N1, the emitter of transistor N1 is grounded, the base of transistor N1 is connected to one end of resistor R12, the other end of resistor R12 is connected to one end of resistor R13 and serves as the SEN port connected to the logic control module, and the other end of resistor R13 is connected to the operating power supply VDD; the output of comparator CMP is connected to the input of the level shifting circuit, and the output of the level shifting circuit outputs a status flag bit FTO to the logic control module.

[0014] Preferably, the resistor R16 for the voltage divider function is a resistor string structure.

[0015] Preferably, the logic control module is an MCU, and the power supply terminal of the MCU is connected to the operating power supply VDD.

[0016] Preferably, determining the abnormal state of the fan based on the waveform and level of the status flag FTO includes:

[0017] In the initial state, the SEN port is configured to a high level through internal pull-up mode. If the status flag FTO is a square wave with a fixed period, it is determined that the fan is in normal working state.

[0018] If the status flag FTO is continuously low, the fan is determined to be in an open circuit state.

[0019] If the status flag FTO is continuously high, it is initially determined that the fan is in a stalled or short-circuited state. At this time, the logic control module will immediately pull the SEN port level low. If the status flag FTO goes low, it is determined that the fan is in a stalled state; otherwise, the fan is in a short-circuited state.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] This invention integrates an adjustable-speed fan drive circuit and multiple anomaly detection circuits on-chip, replacing the existing discrete component design that wastes PCB board space, and achieves the detection function of multiple fan states at low cost. Furthermore, this invention achieves a higher power current amplification function for the fan by using a combination of resistors R0 and R1 and a current amplification tube Q1, and makes sampling simpler by designing a sampling resistor R0' in the sampling detection module. Attached Figure Description

[0022] Figure 1 This is a circuit diagram of an integrated speed-regulating fan and abnormal state detection circuit provided by the present invention. Detailed Implementation

[0023] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. The advantages and features of the present invention will become clearer from the following description. It should be noted that the drawings are all in a very simplified form and use non-precise proportions, and are only used to facilitate and clarify the illustration of the embodiments of the present invention.

[0024] like Figure 1 As shown, where a' is the circuit design integrated into the chip, b' is the current amplification drive module, and c' is the sampling and detection module, this embodiment of the invention specifically provides a circuit integrating a speed-regulating fan and abnormal state detection, including:

[0025] The current amplification drive module provides the fan with a voltage FCC regulated by the LDO, and amplifies the output current of the LDO to drive the fan;

[0026] The logic control module is connected to the current amplification drive module and adjusts the control signal ADJ. <n:0>The fan speed is adjusted by changing the value of the LDO output voltage FCC.

[0027] The sampling and detection module is connected to the fan and to the logic control module via the SEN port. It samples the current of the fan through a sampling resistor and converts it into a voltage V0. After comparing the voltage V0 with the reference voltage Vref, it outputs a voltage signal to the level shifting circuit. The level shifting circuit shifts the voltage signal and outputs a status flag FTO to the logic control module. Based on the waveform and level of the status flag FTO, the abnormal state of the fan is determined.

[0028] The current-boosting drive module includes: a transistor Q1, a resistor R0, and an LDO; the emitter of transistor Q1 and one end of resistor R0 are connected to the operating power supply VCC, the base of transistor Q1 is connected to the other end of resistor R0 and the VIN port of the LDO, and the collector of transistor Q1 is connected to the output terminal of the LDO and the fan. It also includes resistor R1, which is connected between the base of transistor Q1 and the other end of resistor R0. This current-boosting drive module is mainly used by users to enhance the driving capability of the LDO when using high-power fans. In this case, the LDO acts as a voltage clamp, and simultaneously, to divert the power consumption of the LDO to the current-boosting transistor Q1, it reduces the on-chip LDO power, lowers the chip temperature, and protects the chip.

[0029] It also includes an EN port and an ADJ port, through which the LDO is connected to the logic control module.

[0030] The sampling and detection module includes: resistor R0', resistors R12~R13, resistors R15~R16, comparator CMP, transistor N1, and a level shifting circuit. One end of resistor R0' is connected to the fan and the non-inverting input of comparator CMP, and the other end is grounded. The inverting input of comparator CMP is connected to one end of resistor R15 and resistor R16 (which functions as a voltage divider). One end of resistor R16 is connected to the operating power supply VDD, and the other end is grounded. The other end of resistor R15 is connected to the collector of transistor N1, the emitter of transistor N1 is grounded, the base of transistor N1 is connected to one end of resistor R12, and the other end of resistor R12 is connected to one end of resistor R13 and serves as the SEN port connected to the logic control module. The other end of resistor R13 is connected to the operating power supply VDD. The output of comparator CMP is connected to the input of the level shifting circuit, and the output of the level shifting circuit outputs a status flag bit FTO to the logic control module. The aforementioned resistor R0' is used as a sampling resistor with a resistance of approximately 10Ω. At the same time, a resistor with a relatively high power handling capacity is selected.

[0031] The resistor R16 for the voltage divider function is a resistor string structure.

[0032] The logic control module is an MCU, and the power supply terminal of the MCU is connected to the working power supply VDD.

[0033] It also includes the following working principles:

[0034] If the MCU receives a request for heat dissipation due to varying internal temperatures within the device, it can adjust the ADJ... <n:0>The fan speed can be adjusted by changing the FCC voltage. Considering different load conditions of fans, such as high-power fans or fans with large internal losses in the chip, which may cause the chip to overheat, the driving capability and the internal heat loss of the chip are improved by designing a current-boosting transistor Q1.

[0035] The fan current is sampled and converted into voltage V0 by sampling resistor R0'. This voltage is compared with the reference voltage Vref obtained by voltage division by resistor R16. Based on the waveform and level of the status flag FTO, the abnormal state of the fan is determined. Specifically: In the initial state, the SEN port is configured to a high level through internal pull-up mode. If the status flag FTO is a square wave with a fixed period, the fan is determined to be in normal working state. If the status flag FTO is continuously low, the fan is determined to be in an open circuit state. If the status flag FTO is continuously high, it is initially determined to be a stalled or short-circuited state. At this time, the MCU will immediately pull the SEN port level low. If the status flag FTO becomes low, the fan is determined to be in a stalled state; otherwise, the fan is in a short-circuited state.

[0036] The above description is merely a description of preferred embodiments of the present invention and is not intended to limit the scope of the present invention in any way. Any changes or modifications made by those skilled in the art based on the above disclosure shall fall within the protection scope of the claims.

Claims

1. A circuit integrating a speed-regulating fan and abnormal state detection, characterized in that, include: The current amplification drive module provides the fan with a voltage FCC regulated by the LDO, and amplifies the output current of the LDO to drive the fan; The logic control module, connected to the current amplification drive module, adjusts the control signal ADJ. <n:0> The fan speed is adjusted by changing the value of the LDO output voltage FCC. The sampling and detection module is connected to the fan and to the logic control module via the SEN port. It samples the current of the fan through a sampling resistor and converts it into a voltage V0. After comparing the voltage V0 with the reference voltage Vref, it outputs a voltage signal to the level shifting circuit. The level shifting circuit shifts the voltage signal and outputs a status flag FTO to the logic control module. Based on the waveform and level of the status flag FTO, the abnormal state of the fan is determined. The step of determining the abnormal state of the fan based on the waveform and level of the status flag FTO includes: In the initial state, the SEN port is configured to a high level through internal pull-up mode. If the status flag FTO is a square wave with a fixed period, it is determined that the fan is in normal working state. If the status flag FTO is continuously low, the fan is determined to be in an open circuit state. If the status flag FTO is continuously high, it is initially determined that the fan is in a stalled or short-circuited state. At this time, the logic control module will immediately pull the SEN port level low. If the status flag FTO goes low, it is determined that the fan is in a stalled state; otherwise, the fan is in a short-circuited state.

2. The circuit for integrating a speed-regulating fan and abnormal state detection as described in claim 1, characterized in that, The current amplification drive module includes: a transistor Q1, a resistor R0, and an LDO; the emitter of the transistor Q1 and one end of the resistor R0 are connected to the operating power supply VCC, the base of the transistor Q1 is connected to the other end of the resistor R0 and the VIN port of the LDO, and the collector of the transistor Q1 is connected to the output terminal of the LDO and the fan.

3. The circuit for integrating a speed-regulating fan and abnormal state detection as described in claim 2, characterized in that, It also includes a resistor R1, which is connected between the base of the transistor Q1 and the other end of the resistor R0.

4. The circuit for integrating a speed-regulating fan and abnormal state detection as described in claim 2, characterized in that, It also includes an EN port and an ADJ port, through which the LDO is connected to the logic control module.

5. The integrated speed-regulating fan and abnormal state detection circuit as described in claim 1, characterized in that, The sampling and detection module includes: resistor R0', resistors R12~R13, resistors R15~R16, comparator CMP, transistor N1, and a level shifting circuit. One end of resistor R0' is connected to the fan and the non-inverting input of comparator CMP, and the other end is grounded. The inverting input of comparator CMP is connected to one end of resistor R15 and resistor R16 (which functions as a voltage divider). One end of resistor R16 is connected to the operating power supply VDD, and the other end is grounded. The other end of resistor R15 is connected to the collector of transistor N1, the emitter of transistor N1 is grounded, the base of transistor N1 is connected to one end of resistor R12, and the other end of resistor R12 is connected to one end of resistor R13 and serves as the SEN port connected to the logic control module. The other end of resistor R13 is connected to the operating power supply VDD. The output of comparator CMP is connected to the input of the level shifting circuit, and the output of the level shifting circuit outputs a status flag bit FTO to the logic control module.

6. The circuit for integrating a speed-regulating fan and abnormal state detection as described in claim 5, characterized in that, The resistor R16 for the voltage divider function is a resistor string structure.

7. The integrated speed-regulating fan and abnormal state detection circuit as described in claim 1, characterized in that, The logic control module is an MCU, and the power supply terminal of the MCU is connected to the working power supply VDD.

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