Motor current control circuit with voltage detection mechanism

Abstract

The present invention discloses a motor current control circuit with a voltage detection mechanism. The first end of a first lower-bridge transistor is connected to the second end of a first upper-bridge transistor. A node between the first end of the first lower-bridge transistor and the second end of the first upper-bridge transistor is connected to the first end of the motor. The first end of the second lower-bridge transistor is connected to the second end of the second upper-bridge transistor. A zero-current detection circuit detects the voltage at the node to determine whether the current flowing through the motor is zero, thereby outputting a current detection signal. Based on the current detection signal, a control circuit controls a drive circuit to turn on or off each of the first upper-bridge transistor, the first lower-bridge transistor, the second upper-bridge transistor, and the second lower-bridge transistor.

Description

Technical Field

[0001] The present invention relates to a motor, and more particularly to a motor current control circuit with a voltage detection mechanism. Background Art

[0002] Many electronic products generate heat during operation, especially within the enclosed enclosure of a server. Heat generated by each circuit component circulates within the enclosure, heating other circuit components and potentially causing them to overheat and burn. Therefore, fans are essential for cooling these components.

[0003] However, within a fan, the driver circuit switches the multiple transistors in the bridge circuit on and off to drive the motor. During this process, the hot air circulating within the sealed casing can overheat. This overheated air heats the transistors in the bridge circuit, causing them to burn out. Therefore, it is necessary to accurately measure the current flowing through the motor in order to appropriately switch the transistors in the bridge circuit and prevent excessive current from flowing through the transistors, which could damage them. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to address the shortcomings of the prior art and provide a motor current control circuit with a voltage detection mechanism. The circuit is suitable for use in motors and includes a bridge circuit, a drive circuit, a control circuit, and a zero current detection circuit. The bridge circuit includes multiple transistors. The multiple transistors include a first upper bridge transistor, a first lower bridge transistor, a second upper bridge transistor, and a second lower bridge transistor. The first end of the first upper bridge transistor is coupled to a common voltage. The first end of the first lower bridge transistor is connected to the second end of the first upper bridge transistor. A first node between the first end of the first lower bridge transistor and the second end of the first upper bridge transistor is connected to the first end of the motor. The second end of the first lower bridge transistor is grounded. The first end of the second upper bridge transistor is coupled to a common voltage. The first end of the second lower bridge transistor is connected to the second end of the second upper bridge transistor. A second node between the first end of the second lower bridge transistor and the second end of the second upper bridge transistor is connected to the second end of the motor. The second end of the second lower bridge transistor is grounded. The drive circuit is connected to the control ends of each transistor. The zero current detection circuit is connected to the control circuit and the motor. The zero current detection circuit is configured to detect a first voltage at the first node, a voltage at the second node as a second voltage, or both, and to determine whether the current flowing through the motor is zero based on the first voltage, the second voltage, or both, thereby outputting a current detection signal. A drive circuit is connected to the control terminals of each transistor. The drive circuit is configured to drive each transistor on or off. The control circuit is connected to the drive circuit. The control circuit is configured to control the drive circuit based on the current detection signal.

[0005] In one embodiment, the motor current control circuit with a voltage detection mechanism further includes a Hall sensor connected to the control circuit. The Hall sensor is configured to sense changes in magnetic strength of the motor rotor as it rotates, generating positive and negative voltages to output a Hall signal. The control circuit then controls the drive circuit based on the Hall signal.

[0006] In one embodiment, the motor current control circuit with a voltage detection mechanism further includes a Hall signal unit. The Hall signal unit is connected between the Hall sensor and the control circuit. The Hall signal unit is configured to generate a Hall level signal based on the level of the Hall signal received from the Hall sensor. The control circuit controls the driver circuit to turn on or off each transistor based on the Hall level signal.

[0007] In one embodiment, when the control circuit determines, based on the Hall level signal and the current detection signal, that the motor current is not equal to zero in a period near a transition time point of the Hall level signal, the control drive circuit switches the bridge circuit and adjusts the timing of motor commutation so that the motor current is zero in a period near a transition time point of the Hall level signal.

[0008] In one embodiment, the control circuit determines the value of the motor current based on the current detection signal, and when it is determined that the motor current is not equal to zero in the interval near the transition time point of the first voltage signal or the interval near the transition time point of the second voltage signal, the control circuit controls the drive circuit to switch the bridge circuit to extend or shorten the length of time during which the first voltage of the first node is equal to the second voltage of the second node.

[0009] In one embodiment, the motor current control circuit with a voltage detection mechanism further includes a resistor and a current limiting circuit. A first end of the resistor is connected to the second end of the first low-bridge transistor and the second end of the second low-bridge transistor. A second end of the resistor is grounded. The current limiting circuit is connected to the first end of the resistor and the control circuit. The current limiting circuit is configured to detect a voltage across the resistor and, based on the voltage across the resistor, determine whether the current flowing through the resistor is greater than a threshold or within a threshold range, thereby outputting a current limiting signal. The control circuit controls the drive circuit based on the current limiting signal.

[0010] In one embodiment, a zero current detection circuit includes a comparator and a logic circuit. A first input of the comparator is coupled to a reference voltage. A second input of the comparator is connected to a first node. The comparator compares the first voltage with the reference voltage to output a comparison signal. The logic circuit is connected to an output of the comparator and a control circuit. The logic circuit is configured to determine whether the current flowing through the motor is zero based on the comparison signal and output a current detection signal.

[0011] In one embodiment, the zero current detection circuit is connected to the second node and configured to detect a second voltage at the second node, and determine whether the current flowing through the motor is zero according to the second voltage to output a current detection signal.

[0012] In one embodiment, a zero current detection circuit includes a comparator and a logic circuit. A first input of the comparator is connected to a second node. A second input of the comparator is coupled to a reference voltage. The comparator compares a second voltage at the second node with the reference voltage to output a comparison signal. The logic circuit is connected to an output of the comparator and a control circuit. The logic circuit is configured to determine whether the current flowing through the motor is zero based on the comparison signal and output a current detection signal.

[0013] In one embodiment, the zero current detection circuit includes a first comparator, a second comparator, and a logic circuit. The first input terminal of the first comparator is coupled to a first reference voltage. The second input terminal of the first comparator is connected to a first node. The first comparator compares the first voltage with the first reference voltage to output a first comparison signal. The first input terminal of the second comparator is connected to a second node. The second input terminal of the second comparator is coupled to a second reference voltage. The second comparator compares the second voltage of the second node with the second reference voltage to output a second comparison signal. The logic circuit is connected to the output terminal of the first comparator, the output terminal of the second comparator, and the control circuit. The logic circuit is configured to determine whether the current flowing through the motor is zero based on the first comparison signal and the second comparison signal to output a current detection signal.

[0014] As described above, the present invention provides a motor current control circuit with a voltage detection mechanism, which can achieve the following features:

[0015] 1. Detecting a voltage at a first node between a first terminal of the first lower bridge transistor and a second terminal of the first upper bridge transistor to determine whether the current flowing through the motor is zero;

[0016] 2. detecting a voltage at a second node between the first terminal of the second lower bridge transistor and the second terminal of the second upper bridge transistor to determine whether the current flowing through the motor is zero;

[0017] 3. detecting a voltage across a resistor connected to the second end of the first low-bridge transistor and the second end of the second low-bridge transistor to determine whether the current flowing through the motor exceeds a threshold;

[0018] 4. Automatically adjust the motor drive commutation angle based on the detected motor current value;

[0019] 5. The duration of the shutdown interval (a shutdown interval is defined as the voltage at both ends of the driving motor is close, but in reality it will not be completely equal) can be automatically adjusted according to the detected motor current value.

[0020] To further understand the features and technical contents of the present invention, please refer to the following detailed description and drawings of the present invention. However, the drawings provided are only for reference and illustration and are not intended to limit the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 FIG. 1 is a block diagram of a motor current control circuit with a voltage detection mechanism according to a first embodiment of the present invention.

[0022] Figure 2 FIG. 4 is a block diagram of a motor current control circuit with a voltage detection mechanism according to a second embodiment of the present invention.

[0023] Figure 3 FIG. 4 is a block diagram of a motor current control circuit with a voltage detection mechanism according to a third embodiment of the present invention.

[0024] Figure 4 FIG. 4 is a block diagram of a motor current control circuit with a voltage detection mechanism according to a fourth embodiment of the present invention.

[0025] Figure 5 FIG. 5 is a circuit layout diagram of circuit components within a zero current detection circuit of a motor current control circuit with a voltage detection mechanism according to a fifth embodiment of the present invention.

[0026] Figure 6 1 is a signal waveform diagram of a motor current control circuit with a voltage detection mechanism according to a fifth embodiment of the present invention.

[0027] Figure 7 FIG. 1 is a circuit layout diagram of circuit components within a zero current detection circuit of a motor current control circuit with a voltage detection mechanism according to a sixth embodiment of the present invention.

[0028] Figure 8 1 is a signal waveform diagram of a motor current control circuit with a voltage detection mechanism according to a sixth embodiment of the present invention.

[0029] Figure 9 1 is a signal waveform diagram of a motor current control circuit with a voltage detection mechanism according to the seventh embodiment of the present invention.

[0030] Figure 10 1 is a signal waveform diagram of a motor current control circuit with a voltage detection mechanism according to an eighth embodiment of the present invention.

[0031] Figure 11 1 is a signal waveform diagram of a motor current control circuit with a voltage detection mechanism according to a ninth embodiment of the present invention.

[0032] Figure 12 1 is a signal waveform diagram of a motor current control circuit with a voltage detection mechanism according to the tenth embodiment of the present invention. DETAILED DESCRIPTION

[0033] The following is an explanation of the embodiments of the present invention through specific embodiments. Those skilled in the art can understand the advantages and effects of the present invention from the contents disclosed in this specification. The present invention can be implemented or applied through other different specific embodiments, and the details in this specification can also be modified and changed based on different viewpoints and applications without departing from the concept of the present invention. In addition, the drawings of the present invention are only simple schematic illustrations and are not depicted according to actual dimensions. It is stated in advance. The following embodiments will further explain the relevant technical content of the present invention in detail, but the disclosed contents are not intended to limit the scope of protection of the present invention. In addition, the term "or" used herein may include any one or more combinations of the associated listed items depending on the actual situation.

[0034] [First embodiment]

[0035] See also Figure 1 , which is a block diagram of a motor current control circuit with a voltage detection mechanism according to a first embodiment of the present invention.

[0036] The motor current control circuit with voltage detection mechanism of this embodiment may include a bridge circuit HB, a driving circuit 10, a control circuit 20, a zero current detection circuit 30, a Hall sensor 40 and a Hall signal unit 50, but the present invention is not limited thereto. The bridge circuit HB may include multiple transistors, such as Figure 1 Shown are a first upper bridge transistor H1 , a first lower bridge transistor L1 , a second upper bridge transistor H2 , and a second lower bridge transistor L2 .

[0037] A first terminal of the first upper transistor H1 can be coupled to a common voltage VM. A second terminal of the first upper transistor H1 can be connected to a first terminal of the first lower transistor L1. A first node OUT1 between the second terminal of the first upper transistor H1 and the first terminal of the first lower transistor L1 can be connected to a first terminal of the motor MT. A second terminal of the first lower transistor L1 can be grounded. A control terminal of the first upper transistor H1 and a control terminal of the first lower transistor L1 can be connected to the drive circuit 10.

[0038] The first terminal of the second upper transistor H2 can be coupled to the common voltage VM. The second terminal of the second upper transistor H2 can be connected to the first terminal of the second lower transistor L2. A second node OUT2 between the second terminal of the second upper transistor H2 and the first terminal of the second lower transistor L2 can be connected to the second terminal of the motor MT. The second terminal of the second lower transistor L2 can be grounded. The control terminal of the second upper transistor H2 and the control terminal of the second lower transistor L2 can be connected to the drive circuit 10.

[0039] The Hall sensor 40 can be connected to the control circuit 20 and installed in the motor MT. The Hall sensor 40 senses the changes in magnetic strength during the rotation of the motor MT's rotor, generating positive and negative voltages to output Hall signals. The control circuit 20 can be connected to the drive circuit 10. Based on the Hall signals, the control circuit 20 controls the drive circuit 10 to turn on or off the transistors in the bridge circuit HB.

[0040] If necessary, a Hall signal unit 50 can be provided, connected between the Hall sensor 40 and the control circuit 20. The Hall signal unit 50 receives the Hall signal from the Hall sensor 40 and generates a Hall level signal based on the Hall signal level. The control circuit 20 controls the driver circuit 10 to switch each transistor of the bridge circuit HB on or off based on the Hall level signal.

[0041] It is worth noting that the zero-current detection circuit 30 can be connected to a first node OUT1 between the first terminal of the first low-bridge transistor L1 and the second terminal of the first high-bridge transistor H1. The zero-current detection circuit 30 can detect the voltage at the first node OUT1 as a first voltage. Based on the first voltage, the zero-current detection circuit 30 can determine whether the current flowing through the motor MT is zero and output a current detection signal.

[0042] The control circuit 20 can be connected to the zero-current detection circuit 30. The control circuit 20 can receive a current detection signal from the zero-current detection circuit 30 and, based on the current detection signal, control the drive circuit 10 to output a plurality of drive signals GP1, GP2, GN1, and GN2, respectively, to respectively turn on or off the first upper transistor H1, the first lower transistor L1, the second upper transistor H2, and the second lower transistor L2 of the bridge circuit HB. In particular, when the current of the motor MT is zero, the control circuit 20 can control the drive circuit 10 to appropriately switch the bridge circuit HB.

[0043] [Second embodiment]

[0044] See also Figure 2 , which is a block diagram of a motor current control circuit with a voltage detection mechanism according to a second embodiment of the present invention. The same contents as above are not repeated here.

[0045] Unlike the first embodiment in which the zero current detection circuit 30 detects the first voltage of the first node OUT1 between the first end of the first lower bridge transistor L1 and the second end of the first upper bridge transistor H1, the second embodiment in which the zero current detection circuit 30 detects the voltage of the second node OUT2 between the first end of the second lower bridge transistor L2 and the second end of the second upper bridge transistor H2.

[0046] In this embodiment, the zero current detection circuit 30 can determine whether the current flowing through the motor MT is zero based on the second voltage of the second node OUT2 and output a current detection signal. The control circuit 20 can control the driving circuit 10 to appropriately switch the bridge circuit HB based on the current detection signal.

[0047] [Third embodiment]

[0048] See also Figure 3 , which is a block diagram of a motor current control circuit with a voltage detection mechanism according to a third embodiment of the present invention. The same contents as above are not repeated here.

[0049] In this embodiment, the zero-current detection circuit 30 is connected to a first node OUT1 and a second node OUT2. Based on (the difference between) a first voltage at the first node OUT1 and a second voltage at the second node OUT2, it determines whether the current flowing through the motor MT is zero, thereby outputting a current detection signal. The control circuit 20 controls the drive circuit 10 to appropriately switch the bridge circuit HB based on the current detection signal.

[0050] [Fourth embodiment]

[0051] See also Figure 4 , which is a block diagram of a motor current control circuit with a voltage detection mechanism according to a fourth embodiment of the present invention. The same contents as above are not repeated here.

[0052] In this embodiment, the motor current control circuit may include a resistor R and a current limiting circuit 60. A first end of the resistor R may be connected to the second end of the first low-bridge transistor L1 and the second end of the second low-bridge transistor L2. A second end of the resistor R may be grounded.

[0053] The current limiting circuit 60 can be connected to the first end of the resistor R and the control circuit 20. The current limiting circuit 60 can detect the voltage of the resistor R and determine whether the current flowing through the resistor R is greater than a threshold or falls within a threshold range based on the detected voltage of the resistor R, thereby outputting a current limiting signal.

[0054] The control circuit 20 may be connected to the current limiting circuit 60. The control circuit 20 may control the driving circuit 10 to appropriately switch the bridge circuit HB according to the current limiting signal received from the current limiting circuit 60 to limit the current flowing through the bridge circuit HB and the motor MT.

[0055] [Fifth embodiment]

[0056] See also Figure 5 and Figure 6 ,in Figure 5 FIG4 is a circuit layout diagram of circuit components within a zero current detection circuit of a motor current control circuit with a voltage detection mechanism according to a fifth embodiment of the present invention; Figure 6 1 is a signal waveform diagram of a motor current control circuit with a voltage detection mechanism according to a fifth embodiment of the present invention. The same contents as above are not repeated here.

[0057] The zero current detection circuit of the motor current control circuit of this embodiment (for example Figure 1 、 Figure 3 and Figure 4 The zero current detection circuit 30 shown may include the following Figure 5 The comparator 311 and the logic circuit 312 are shown.

[0058] A first input terminal, such as a non-inverting input terminal, of the comparator 311 may be coupled to a reference voltage Vref1. A second input terminal, such as an inverting input terminal, of the comparator 311 may be connected to a first node OUT1. The comparator 311 may compare a first voltage Vout1 at the first node OUT1 with the reference voltage Vref1 to output a first comparison signal.

[0059] The logic circuit 312 can be connected to the output terminal of the comparator 311 and the control circuit (eg Figure 1 、 Figure 2 or Figure 3 The control circuit 20 shown in FIG. 20 ). The logic circuit 312 may be configured as follows: Figure 6 The first comparison signal is received from the comparator 311 within a sampling time (for example, the switching time) framed by the dotted box, and the current (Im1) flowing through the motor MT is determined to be zero based on the level of the first comparison signal to output a current detection signal to the control circuit 20.

[0060] For example, when the logic circuit 312 receives the first comparison signal at a low level, the logic circuit 312 determines that the first voltage Vout1 at the first node OUT1 is greater than the reference voltage Vref1. In this case, the current flowing through the motor MT is not zero. Conversely, when the logic circuit 312 receives the first comparison signal at a high level, the logic circuit 312 determines that the first voltage Vout1 at the first node OUT1 is less than the reference voltage Vref1. Therefore, the current flowing through the motor MT is zero.

[0061] [Sixth embodiment]

[0062] See also Figure 7 and Figure 8 ,in Figure 7 FIG1 is a circuit layout diagram of circuit components within a zero current detection circuit of a motor current control circuit with a voltage detection mechanism according to a sixth embodiment of the present invention; Figure 8 1 is a signal waveform diagram of a motor current control circuit with a voltage detection mechanism according to a sixth embodiment of the present invention. The same contents as above are omitted here for brevity.

[0063] The zero current detection circuit of the motor current control circuit of this embodiment (for example Figure 2 、 Figure 3 and Figure 4 The zero current detection circuit 30 shown may include the following Figure 7 The comparator 321 and the logic circuit 322 are shown.

[0064] A first input terminal, such as a non-inverting input terminal, of the comparator 321 can be connected to the second node OUT2. A second input terminal, such as an inverting input terminal, of the comparator 321 can be coupled to a reference voltage Vref2. The comparator 321 can compare the second voltage Vout2 at the second node OUT2 with the reference voltage Vref2 to output a second comparison signal. The reference voltage Vref2 can be equal to or different from the reference voltage Vref1.

[0065] The logic circuit 322 can be connected to the output terminal of the comparator 321 and the control circuit 20. ... Figure 8 The second comparison signal is received from the comparator 321 within a sampling time (eg, the switching time) framed by the dotted box, and the current (Im2) flowing through the motor MT is determined to be zero based on the second comparison signal to output a current detection signal.

[0066] For example, when the logic circuit 322 receives the second comparison signal at a low level, the logic circuit 322 determines that the second voltage Vout2 at the second node OUT2 is less than the reference voltage Vref2. In this case, the current flowing through the motor MT is not zero. Conversely, when the logic circuit 322 receives the second comparison signal at a high level, the logic circuit 322 determines that the second voltage Vout2 at the second node OUT2 is greater than the reference voltage Vref2. In this case, the current flowing through the motor MT is zero.

[0067] like Figure 3 or Figure 4 The zero current detection circuit 30 of the motor current control circuit shown may include the following: Figure 5 The comparator 311 and the logic circuit 312 are used to detect the first voltage Vout1 of the first node OUT1, and include Figure 7 The illustrated comparator 321 and logic circuit 322 are used to detect the second voltage Vout2 at the second node OUT2. In practice, the zero-current detection circuit may include only one logic circuit connected to the output terminals of the comparator 311 (serving as the first comparator) and the comparator 321 (serving as the second comparator), and configured to perform the same operations as the logic circuits 312 and 322.

[0068] [Seventh embodiment]

[0069] See also Figure 9, which is a signal waveform diagram of a motor current control circuit with a voltage detection mechanism according to the seventh embodiment of the present invention. The same contents as above are not repeated here.

[0070] The control circuit 20 can generate a signal of the first voltage Vout1 of the first node OUT1 minus a signal of the second voltage Vout2 of the second node OUT2. Figure 9 The voltage signal VS1 is shown.

[0071] It is worth noting that the control circuit 20 can receive the following signals from the Hall signal unit 50: Figure 9 The Hall level signal HS shown in FIG. 1 can be received from the zero current detection circuit 30 as shown in FIG. Figure 9 Then, the control circuit 20 can determine whether the current of the motor MT in the current detection signal IMS1 is equal to zero at the transition time point of the Hall level signal HS according to the Hall level signal HS and the current detection signal IMS1.

[0072] In this embodiment, the transition time point may be, for example, a time point from a low level to a high level (ie, a rising edge time point), or may actually be a time point from a high level to a low level (ie, a falling edge time point).

[0073] When the control circuit 20 determines that the current of the motor MT is not equal to zero at the transition time point of the Hall level signal HS, the control circuit 20 can control the driving circuit 10 to switch the bridge circuit HB to adjust the phase of the Hall level signal HS so that the current of the motor MT is zero at the transition time point of the Hall level signal HS.

[0074] For example, when the control circuit 20 determines that the current of the motor MT is not equal to zero but is less than zero at the time point when the Hall level signal HS changes from a low level to a high level (i.e., the transition time point), the control circuit 20 may shift the phase of the voltage signal VS1 forward by a phase angle PE, so that Figure 9 As shown, the current of the motor MT of the current detection signal IMS1 is zero near the time point of the rising edge of the Hall level signal HS (ie, the transition time point).

[0075] Conversely, when the control circuit 20 determines that the current of the motor MT is not equal to zero but is greater than zero at the time point when the Hall level signal HS changes from a low level to a high level (i.e., the transition time point), the control circuit 20 may shift the phase of the voltage signal VS1 backward by a phase angle PE so that the current of the motor MT indicated by the current detection signal IMS1 is zero near the transition time point interval of the Hall level signal HS.

[0076] As described above, the control circuit 20 can adjust the transition timing interval of the Hall level signal HS to coincide with the time point at which the current flowing through the motor MT reaches zero. In practice, the Hall level signal HS can be replaced with the back-EMF signal of the motor MT. The control circuit 20 can adjust the transition timing interval of the back-EMF signal to coincide with the time point at which the current flowing through the motor MT reaches zero, and can also adjust the phase of the Hall level signal HS to have a predetermined phase difference with the back-EMF signal.

[0077] [Eighth embodiment]

[0078] See also Figure 10 , which is a signal waveform diagram of a motor current control circuit with a voltage detection mechanism according to an eighth embodiment of the present invention. The same contents as above are not repeated here.

[0079] The control circuit 20 may receive the following information from the zero current detection circuit 30: Figure 10 The control circuit 20 can generate a voltage signal having multiple square waves by subtracting the first voltage Vout1 at the first node OUT1 from the second voltage Vout2 at the second node OUT2. The difference between the first voltage Vout1 at the first node OUT1 and the second voltage Vout2 at the second node OUT2 is the phase voltage of the motor.

[0080] The control circuit 20 can determine whether the current of the motor MT of the current detection signal IMS2 is equal to zero at the transition time point of the voltage signal (eg, the time point when the voltage changes from zero to a value greater than zero) based on the voltage signal and the current detection signal IMS2.

[0081] When the control circuit 20 determines that the current detection signal IMS2 is not equal to zero, for example, is less than zero, at the transition time point of the voltage signal VS2, the drive circuit 10 can be controlled to switch the bridge circuit HB to extend the time length during which the first voltage Vou1 of the first node OUT1 is equal to the second voltage Vou2 of the second node OUT2 (controlling the phase voltage of the motor MT to be close to zero). Figure 10 As shown in FIG, the phase angle OFA is delayed, so that the phase voltage of the motor MT becomes as follows Figure 10 The voltage signal VS2 shown causes the current of the motor MT to be zero at the transition time point.

[0082] On the contrary, when the control circuit 20 determines that the current detection signal IMS2 is greater than zero at the transition time point of the voltage signal, it can control the drive circuit 10 to switch the bridge circuit HB to shorten the time length during which the first voltage Vou1 of the first node OUT1 is equal to the second voltage Vou2 of the second node OUT2 (control the phase voltage of the motor MT to be close to zero), and delay the phase angle OFA forward so that the current of the motor MT is zero at the transition time point.

[0083] [Ninth embodiment]

[0084] See also Figure 11 , which is a signal waveform diagram of a motor current control circuit with a voltage detection mechanism according to the ninth embodiment of the present invention.

[0085] The zero current detection circuit 30 can detect a first voltage signal VTS1 at the first node OUT1, a second voltage signal VTS2 at the second node OUT2, or both, and accordingly determine whether the current flowing through the motor MT is zero to output a current detection signal ITS1.

[0086] The control circuit 20 can determine whether the current of the motor MT indicated by the current detection signal ITS1 is equal to zero at the transition time point (nearby interval) of the Hall level signal HLS1 (or actually the commutation signal PHS1 ).

[0087] In this embodiment, the transition time point may be, for example, a time point from a low level to a high level (ie, a rising edge time point), or may actually be a time point from a high level to a low level (ie, a falling edge time point).

[0088] When the control circuit 20 determines that the current of the motor MT is not equal to zero at the transition time of the Hall level signal HLS1 (or actually the commutation signal PHS1), the control circuit 20 can control the driving circuit 10 to switch the bridge circuit HB to adjust the phase of the phase voltage (or actually the phase of the commutation signal PHS1), for example, by shifting the phase angle PE2 so that the current of the motor MT is zero at the transition time of the Hall level signal HLS1 (or actually the commutation signal PHS1).

[0089] [Tenth embodiment]

[0090] See also Figure 12 , which is a signal waveform diagram of a motor current control circuit with a voltage detection mechanism according to the tenth embodiment of the present invention.

[0091] The zero current detection circuit 30 can detect a first voltage signal VTS1 at the first node OUT1, a second voltage signal VTS2 at the second node OUT2, or both, and accordingly determine whether the current flowing through the motor MT is zero to output a current detection signal ITS2.

[0092] Based on the current detection signal ITS2, the control circuit 20 determines whether the current of the motor MT indicated by the current detection signal ITS2 is equal to zero at the commutation time point (i.e., the transition time point) of the commutation signal PHS2 (or, in practice, the Hall level signal HLS2) of the motor MT. In this embodiment, the transition time point can be, for example, the time point when the level changes from a low level to a high level (i.e., the time point of the rising edge), or the time point when the level changes from a high level to a low level (i.e., the time point of the falling edge).

[0093] When the control circuit 20 determines that the current detection signal ITS2 is not equal to zero at the commutation time point of the commutation signal PHS2, the control circuit 20 can control the drive circuit 10 to switch the bridge circuit HB to adjust the phase of the commutation signal PHS2 of the motor MT (or actually the phase of the phase voltage), for example, by adjusting the closing interval angle OFA2 so that the current of the motor MT is zero at the commutation time point of the commutation signal PHS2 of the motor MT (i.e., the transition time point).

[0094] In summary, the present invention provides a motor current control circuit with a voltage detection mechanism, which can achieve the following features:

[0095] 1. Detecting a voltage at a first node between a first terminal of the first lower bridge transistor and a second terminal of the first upper bridge transistor to determine whether the current flowing through the motor is zero;

[0096] 2. detecting a voltage at a second node between the first terminal of the second lower bridge transistor and the second terminal of the second upper bridge transistor to determine whether the current flowing through the motor is zero;

[0097] 3. detecting a voltage across a resistor connected to the second end of the first low-bridge transistor and the second end of the second low-bridge transistor to determine whether the current flowing through the motor exceeds a threshold;

[0098] 4. Automatically adjust the motor drive commutation angle based on the detected motor current value;

[0099] 5. The duration of the shutdown interval (a shutdown interval is defined as the voltage at both ends of the driving motor is close, but in reality it will not be completely equal) can be automatically adjusted according to the detected motor current value.

[0100] The contents disclosed above are only preferred feasible embodiments of the present invention and are not intended to limit the claims of the present invention. Therefore, any equivalent technical changes made using the contents of the present invention's description and drawings are included in the claims of the present invention.

Claims

1. A motor current control circuit with a voltage detection mechanism, suitable for a motor, characterized in that: The motor current control circuit with voltage detection mechanism includes: A bridge circuit includes a plurality of transistors, wherein the plurality of transistors include: a first upper bridge transistor, wherein a first terminal of the first upper bridge transistor is coupled to a shared voltage; a first lower bridge transistor, wherein a first end of the first lower bridge transistor is connected to the second end of the first upper bridge transistor, a first node between the first end of the first lower bridge transistor and the second end of the first upper bridge transistor is connected to the first end of the motor, and the second end of the first lower bridge transistor is grounded; a second upper bridge transistor, wherein a first terminal of the second upper bridge transistor is coupled to the shared voltage; as well as a second lower bridge transistor, wherein a first end of the second lower bridge transistor is connected to the second end of the second upper bridge transistor, a second node between the first end of the second lower bridge transistor and the second end of the second upper bridge transistor is connected to the second end of the motor, and the second end of the second lower bridge transistor is grounded; a zero current detection circuit connected to the motor, the zero current detection circuit being configured to detect the voltage of the first node as a first voltage, the voltage of the second node as a second voltage, or both the voltage of the first node as a first voltage and the voltage of the second node as a second voltage, and to determine whether the current flowing through the motor is zero based on the first voltage, the second voltage, or both the first voltage and the second voltage, and to output a current detection signal; a driving circuit connected to the control terminal of each of the transistors, wherein the driving circuit is configured to drive each of the transistors to turn on or off; as well as a control circuit connected to the driving circuit and the zero current detection circuit, wherein the control circuit is configured to control the driving circuit according to the current detection signal; The control circuit determines the value of the current of the motor based on the current detection signal, and when it determines that the current of the motor is not equal to zero in the interval near the transition time point of the signal of the first voltage or the interval near the transition time point of the signal of the second voltage, controls the drive circuit to switch the bridge circuit to extend or shorten the time length that the first voltage of the first node is equal to the second voltage of the second node.

2. The motor current control circuit with a voltage detection mechanism according to claim 1, wherein: The motor current control circuit with voltage detection mechanism further includes: A Hall sensor is connected to the control circuit. The Hall sensor is configured to sense changes in magnetic strength when the motor rotor rotates, and to generate positive and negative voltages to output Hall signals. The control circuit controls the drive circuit based on the Hall signals.

3. The motor current control circuit with a voltage detection mechanism according to claim 2, wherein: The motor current control circuit with voltage detection mechanism further includes: The Hall signal unit is connected between the Hall sensor and the control circuit. The Hall signal unit is configured to generate a Hall level signal according to the level of the Hall signal received from the Hall sensor. The control circuit controls the driving circuit according to the Hall level signal.

4. The motor current control circuit with a voltage detection mechanism according to claim 3, wherein: When the control circuit determines, based on the Hall level signal and the current detection signal, that the current of the motor is not equal to zero in the interval near the transition time point of the Hall level signal, the control circuit controls the drive circuit to switch the bridge circuit to adjust the time point at which the motor commutation occurs so that the current of the motor is zero in the interval near the transition time point of the Hall level signal.

5. The motor current control circuit with voltage detection mechanism according to claim 1, wherein: The motor current control circuit with voltage detection mechanism further includes: a resistor, a first end of the resistor being connected to the second end of the first lower bridge transistor and the second end of the second lower bridge transistor, and a second end of the resistor being grounded; and A current limiting circuit is connected to the first end of the resistor and the control circuit. The current limiting circuit is configured to detect a voltage across the resistor and, based on the voltage across the resistor, determine whether a current flowing through the resistor is greater than a threshold or falls within a threshold range to output a current limiting signal. The control circuit controls the drive circuit based on the current limiting signal.

6. The motor current control circuit with voltage detection mechanism according to claim 1, wherein: The zero current detection circuit comprises: a comparator, wherein a first input terminal of the comparator is coupled to a reference voltage, a second input terminal of the comparator is connected to the first node, and the comparator compares the first voltage with the reference voltage to output a comparison signal; as well as The logic circuit is connected to the output terminal of the comparator and the control circuit, and is configured to determine whether the current flowing through the motor is zero according to the comparison signal to output the current detection signal.

7. The motor current control circuit with a voltage detection mechanism according to claim 1, wherein: The zero current detection circuit is connected to the second node. The zero current detection circuit is configured to detect a second voltage of the second node, and determine whether the current flowing through the motor is zero based on the second voltage to output the current detection signal.

8. The motor current control circuit with a voltage detection mechanism according to claim 1, wherein: The zero current detection circuit comprises: a comparator, wherein a first input terminal of the comparator is connected to the second node, a second input terminal of the comparator is coupled to a reference voltage, and the comparator compares the second voltage of the second node with the reference voltage to output a comparison signal; as well as The logic circuit is connected to the output terminal of the comparator and the control circuit, and is configured to determine whether the current flowing through the motor is zero according to the comparison signal to output the current detection signal.

9. The motor current control circuit with a voltage detection mechanism according to claim 1, wherein: The zero current detection circuit comprises: a first comparator, wherein a first input terminal of the first comparator is coupled to a first reference voltage, a second input terminal of the first comparator is connected to the first node, and the first comparator compares the first voltage with the first reference voltage to output a first comparison signal; a second comparator, wherein a first input terminal of the second comparator is connected to the second node, a second input terminal of the second comparator is coupled to a second reference voltage, and the second comparator compares the second voltage of the second node with the second reference voltage to output a second comparison signal; as well as A logic circuit is connected to the output end of the first comparator, the output end of the second comparator and the control circuit. The logic circuit is configured to determine whether the current flowing through the motor is zero based on the first comparison signal and the second comparison signal to output the current detection signal.

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