Speed regulation driving and anomaly detection circuit of cooling fan

Abstract

The invention belongs to the technical field of integrated circuits, and particularly relates to a speed regulation driving and anomaly detection circuit of a cooling fan. Comprising a current expansion driving module for providing a voltage FCC stabilized by an LDO for a fan and performing current expansion on an output current of the LDO to drive the fan; the logic control module is connected with the current expansion driving module and is used for adjusting a control signal ADJlt; n: 0gt; the value of the voltage FCC output by the LDO is changed, so that the speed of the fan is regulated; and the sampling detection module is connected with the logic control module and the VIN port of the LDO, samples the current of the fan through a sampling resistor, converts the current into a voltage V0, compares the voltage V0 with a reference voltage Vref, and outputs a voltage signal to the level shift circuit. The speed-adjustable fan driving circuit is integrated, detection of various abnormal states of the fan is achieved, and the speed-adjustable fan driving circuit has the outstanding advantages of being simple in PCB layout and low in cost.

Description

Technical Field

[0001] The present invention belongs to the technical field of integrated circuits, and in particular relates to a speed regulation drive and abnormality detection circuit for a heat dissipation fan. Background Art

[0002] With the increasing integration of electronic circuits, heat dissipation has become a critical issue for power electronics. This is especially true when circuits operate at high power and voltage, generating significant heat over extended periods. Without timely heat dissipation, prolonged operation can lead to elevated device temperatures, potentially shortening device lifespan and even damaging them. Consequently, device heat dissipation issues are becoming increasingly prominent.

[0003] To effectively overcome the heat dissipation challenges of device circuits, fans are widely used in the integrated circuit field as an efficient heat dissipation method. Currently, there are various fan operating status detection technologies on the market, a typical approach being to monitor the fan motor status. For example, patent publication number CN101113992A describes a fan detection circuit that includes an overcurrent protection device, a clamping circuit, a voltage divider circuit, and an electronic switch. The overcurrent protection device's terminals are connected to the fan power supply and the first terminal of the fan interface, respectively. The clamping circuit comprises D1 and D2, and the voltage divider circuit comprises R2 and R3. The clamping circuit and voltage divider circuit are connected between the second terminal of the fan interface and ground. The control terminal of the electronic switch device, T1, is connected to the central junction of the voltage divider circuit. The circuit detects fan status by measuring the fan power supply current. The clamping voltage of the diode during forward conduction is used to determine whether the fan is in place and whether there is a short circuit or short-circuit fault. The turn-on characteristic of a bipolar transistor is utilized to convert the fan operating status into a digital value for use by the monitoring system.

[0004] However, existing fan detection is mostly implemented through discrete device designs, which occupy a large PCB board area and have high discrete device costs. At the same time, using a single fan detection method, the fan speed cannot be adjusted and multiple abnormal conditions cannot be detected. Summary of the Invention

[0005] The purpose of the present invention is to provide a speed regulation drive and abnormality detection circuit for a cooling fan. Compared with a single fan detection or direct drive fan solution, the present invention integrates an adjustable speed fan drive circuit and realizes detection of multiple fan abnormal conditions, with the outstanding advantages of simple PCB board layout and low cost.

[0006] To solve the above technical problems, the present invention provides a speed regulation drive and abnormality detection circuit for a cooling fan, comprising:

[0007] The current expansion drive module provides the fan with a voltage FCC stabilized by an LDO and expands the output current of the LDO to drive the fan;

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

[0009] a sampling detection module connected to the logic control module and the VIN port of the LDO, sampling the fan current through a sampling resistor and converting it into a voltage V0, comparing the voltage V0 with a reference voltage Vref, and outputting a voltage signal to a level shift circuit, which performs level shifting on the voltage signal and outputs a status flag FTO, and determines the abnormal state of the fan according to the waveform and level of the status flag FTO;

[0010] The step of determining the abnormal state of the fan according to the waveform and level of the status flag FTO includes:

[0011] In the initial state, the SEN port is configured to a high level through the 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 a normal working state;

[0012] If the status flag FTO is continuously at a low level, it is determined that the fan is in an open circuit state;

[0013] If the status flag FTO is continuously high, it is preliminarily judged to be a stalled or short-circuit state. At this time, the MCU will immediately pull down the SEN port level. If the status flag FTO is still high, it is judged that the fan is in a short-circuit state, otherwise the fan is in a stalled state.

[0014] Preferably, the current expansion 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 working 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 end of the LDO and the fan.

[0015] Preferably, a resistor R1 is further included, and the resistor R1 is connected between the base of the transistor Q1 and the other end of the resistor R0.

[0016] Preferably, it further comprises an EN port and an ADJ port, and the LDO is connected to the logic control module via the EN port and the ADJ port respectively.

[0017] Preferably, the sampling detection module includes: resistors R2 to R3, resistors R11 to R14, transistor Q2, comparator CMP, transistor N1 and level shift circuit; one end of the resistor R2 is connected to the VIN port of the LDO, and the other end is connected to the base of the transistor Q2; the emitter of the transistor Q2 is connected to the working power supply VCC, the collector of the transistor Q2 is connected to one end of the resistor R3 and the non-inverting input end of the comparator CMP, and the other end of the resistor R3 is grounded; the inverting input end of the comparator CMP is connected to one end of the resistor R11 and the resistor R14 with a voltage divider function, and the voltage divider function One end of the resistor R14 is connected to the working power supply VDD, and the other end is grounded; the other end of the resistor R11 is connected to the collector of the transistor N1, the emitter of the transistor N1 is grounded, and the base of the transistor N1 is connected to one end of the resistor R12, the other end of the resistor R12 is connected to one end of the resistor R13 and is connected to the logic control module as a SEN port, and the other end of the resistor R13 is connected to the working power supply VDD; the output end of the comparator CMP is connected to the input end of the level shift circuit, and the output end of the level shift circuit outputs the status flag FTO to the logic control module.

[0018] Preferably, the resistor R14 with the voltage dividing function is a resistor string structure.

[0019] Preferably, the logic control module is an MCU, and the power supply terminal of the MCU is connected to the working power supply VDD.

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

[0021] The present invention integrates an adjustable speed fan drive circuit and multiple abnormality detection circuits on-chip, replacing the existing discrete device design that wastes PCB board area, thereby achieving the detection function of multiple fan states at low cost. Moreover, the present invention realizes the function of expanding the fan's current with higher power by using a combination of resistors R0, R1 and a flow expansion tube Q1. The resistor R0 can also be used as a sampling resistor, and cooperates with the transistor Q2 and resistor R3 designed in the sampling detection module to make sampling simpler and flexibly realize the detection of multiple working states of the fan. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 The present invention provides a circuit diagram of a speed regulating drive and abnormality detection circuit for a heat dissipation fan. DETAILED DESCRIPTION

[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 more apparent from the following description. It should be noted that the drawings are greatly simplified and not to exact scale, and are only used to facilitate and clearly illustrate the embodiments of the present invention.

[0024] like Figure 1 As shown, a' is a circuit design integrated in the chip, b' is a current expansion drive module; c' is a sampling detection module. The embodiment of the present invention specifically provides a speed regulation drive and abnormality detection circuit for a cooling fan, including:

[0025] The current expansion drive module provides the fan with a voltage FCC stabilized by an LDO and expands the output current of the LDO to drive the fan;

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

[0027] a sampling detection module connected to the logic control module and the VIN port of the LDO, sampling the fan current through a sampling resistor and converting it into a voltage V0, comparing the voltage V0 with a reference voltage Vref, and outputting a voltage signal to a level shift circuit, which performs level shifting on the voltage signal and outputs a status flag FTO, and determines the abnormal state of the fan according to the waveform and level of the status flag FTO;

[0028] The current expansion 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 working 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 end of the LDO and the fan. The above-mentioned resistor R0 can not only be used in combination with the current expansion transistor Q1 to achieve a higher power current expansion function, but can also be used as a sampling resistor for fan status detection. When the short-circuit detection function is used, the resistor R0 needs to be a resistor with high power handling and high precision. When the short-circuit detection function is not used, it is not necessary to use a resistor with high precision and high power handling.

[0029] The system further includes a resistor R1 , which is connected between the base of the transistor Q1 and the other end of the resistor R0 .

[0030] 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.

[0031] The sampling detection module includes: resistors R2 to R3, resistors R11 to R14, transistor Q2, comparator CMP, transistor N1 and level shift circuit; one end of the resistor R2 is connected to the VIN port of the LDO, and the other end is connected to the base of the transistor Q2; the emitter of the transistor Q2 is connected to the working power supply VCC, the collector of the transistor Q2 is connected to one end of the resistor R3 and the non-inverting input end of the comparator CMP, and the other end of the resistor R3 is grounded; the inverting input end of the comparator CMP is connected to one end of the resistor R11 and the resistor R14 with a voltage divider function, and the voltage divider function One end of the resistor R14 is connected to the working power supply VDD, and the other end is grounded; the other end of the resistor R11 is connected to the collector of the transistor N1, the emitter of the transistor N1 is grounded, and the base of the transistor N1 is connected to one end of the resistor R12. The other end of the resistor R12 is connected to one end of the resistor R13 and is connected to the logic control module as a SEN port. The other end of the resistor R13 is connected to the working power supply VDD; the output end of the comparator CMP is connected to the input end of the level shift circuit, and the output end of the level shift circuit outputs the status flag FTO to the logic control module.

[0032] The resistor R14 for the voltage dividing function is a resistor string structure.

[0033] The logic control module is an MCU, and the power supply terminal of the MCU is connected to the working power supply VDD.

[0034] It also includes the following working principles:

[0035] MCU receives the need for heat dissipation when the device is at different temperatures, and can adjust ADJ <n:0>The FCC voltage is changed to adjust the fan speed. In view of the different load conditions of fans, such as high-power fans or large losses in the chip, which lead to chip overheating, the flow expansion tube Q1 is designed to improve the driving capability and reduce the heat loss in the chip.

[0036] The fan current is sampled and converted into a voltage V0 through the sampling resistor R0, transistor Q2, and resistor R3. The voltage V0 is compared with the reference voltage Vref divided by the resistor R14, and the abnormal state corresponding to the fan is determined based on the waveform and level of the status flag FTO. That is, in the initial state, the SEN port is configured to a high level through the internal pull-up mode. If the status flag FTO is a square wave with a fixed period, the fan is determined to be in a 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 (when the sampled converted voltage V0>Vref), it is preliminarily determined to be a stalled or short-circuited state. At this time, the MCU will immediately pull down the SEN port level. If the status flag FTO is still high (when the sampled converted voltage V0>Vref', where Vref' is the reference voltage after the level is pulled high), the fan is determined to be in a short circuit state; otherwise, the fan is in a stalled state.

[0037] The above description is only a description of the preferred embodiments of the present invention and does not limit the scope of the present invention. Any changes and modifications made by ordinary technicians in the field of the present invention based on the above disclosure shall fall within the scope of protection of the claims.

Claims

1. A speed regulation drive and abnormality detection circuit for a cooling fan, characterized in that: include: The current expansion drive module provides the fan with a voltage FCC stabilized by an LDO and expands the output current of the LDO to drive the fan; The logic control module is connected to the current expansion drive module and adjusts the control signal ADJ <n:0> By changing the value of the voltage FCC output by the LDO, the speed of the fan is adjusted; a sampling detection module connected to the logic control module and the VIN port of the LDO, sampling the fan current through a sampling resistor and converting it into a voltage V0, comparing the voltage V0 with a reference voltage Vref, and outputting a voltage signal to a level shift circuit, which performs level shifting on the voltage signal and outputs a status flag FTO, and determines the abnormal state of the fan according to the waveform and level of the status flag FTO; The step of determining the abnormal state of the fan according to the waveform and level of the status flag FTO includes: In the initial state, the SEN port is configured to a high level through the 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 a normal working state; If the status flag FTO is continuously at a low level, it is determined that the fan is in an open circuit state; If the status flag FTO is continuously high, it is preliminarily judged to be a stalled or short-circuit state. At this time, the MCU will immediately pull down the SEN port level. If the status flag FTO is still high, it is judged that the fan is in a short-circuit state, otherwise the fan is in a stalled state.

2. A speed regulating drive and abnormality detection circuit for a cooling fan according to claim 1, characterized in that: The current expansion 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 working 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 end of the LDO and the fan.

3. A speed regulating drive and abnormality detection circuit for a cooling fan as claimed in claim 2, characterized in that: The system further includes a resistor R1 , which is connected between the base of the transistor Q1 and the other end of the resistor R0 .

4. A speed regulating drive and abnormality detection circuit for a heat dissipation fan as claimed in claim 2, characterized in that: 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.

5. The speed regulation drive and abnormality detection circuit of a cooling fan according to claim 1, characterized in that: The sampling detection module includes: resistors R2 to R3, resistors R11 to R14, transistor Q2, comparator CMP, transistor N1 and level shift circuit; one end of the resistor R2 is connected to the VIN port of the LDO, and the other end is connected to the base of the transistor Q2; the emitter of the transistor Q2 is connected to the working power supply VCC, the collector of the transistor Q2 is connected to one end of the resistor R3 and the non-inverting input end of the comparator CMP, and the other end of the resistor R3 is grounded; the inverting input end of the comparator CMP is connected to one end of the resistor R11 and the resistor R14 with a voltage divider function, and the voltage divider function One end of the resistor R14 is connected to the working power supply VDD, and the other end is grounded; the other end of the resistor R11 is connected to the collector of the transistor N1, the emitter of the transistor N1 is grounded, and the base of the transistor N1 is connected to one end of the resistor R12. The other end of the resistor R12 is connected to one end of the resistor R13 and is connected to the logic control module as a SEN port. The other end of the resistor R13 is connected to the working power supply VDD; the output end of the comparator CMP is connected to the input end of the level shift circuit, and the output end of the level shift circuit outputs the status flag FTO to the logic control module.

6. A speed regulating drive and abnormality detection circuit for a heat dissipation fan as claimed in claim 5, characterized in that: The resistor R14 for the voltage dividing function is a resistor string structure.

7. A speed regulating drive and abnormality detection circuit for a heat dissipation fan according to claim 1, characterized in that: The logic control module is an MCU, and the power supply terminal of the MCU is connected to a working power supply VDD.

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