Patent Publication Number: US-2023155525-A1

Title: Motor unit

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a motor unit, and more particularly, to a motor unit which may be applied to a high-voltage configuration. 
     2. Description of the Prior Art 
     In general, the pin of the traditional integrated circuit may be set to be at the high/low level, such that the user is capable of selecting the needed function. However, by such setting method, the adjustable function and the resolution may be insufficient. In addition, the motor generates switching noise when operating in an operation mode. Such switching noise may affect accuracy of the adjustable function. When the motor controller is applied to a high-voltage configuration, the motor results in more noise. Thus, a new technology is needed to overcome the drawback of the prior art. 
     SUMMARY OF THE INVENTION 
     According to the present invention, a motor unit which may provide a better function and resolution for each parameter is provided. The motor unit comprises a motor controller and a voltage divider, where the voltage divider may be a resistive voltage divider. The motor controller may be implemented in an integrated circuit chip while the voltage divider may be implemented on a printed circuit board. The motor controller comprises a driving circuit, a control unit, an analog-to-digital converter, a switching circuit, a voltage converter, and a counting unit. The motor controller receives a power supply voltage, such that the driving circuit is biased at the power supply voltage. The voltage converter converts the power supply voltage into an input voltage, where the control unit, the analog-to-digital converter, the switching circuit, the counting unit, and the voltage divider are biased at the input voltage. The voltage converter may be a step-down converter, such that the power supply voltage is greater than the input voltage. For example, the power supply voltage may be equal to 12 volts while the input voltage may be equal to 5 volts. Therefore, both the motor unit and the motor controller may be applied to a high-voltage configuration. The driving circuit includes a first transistor, a second transistor, a third transistor, a fourth transistor, a first terminal, and a second terminal for driving a motor. 
     The voltage divider receives the input voltage, so as to generate a first voltage, a second voltage, and a third voltage. The voltage divider may comprise a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, and a sixth resistor. The first resistor is coupled to the second resistor and receives the input voltage for generating the first voltage to the switching circuit. The third resistor is coupled to the fourth resistor and receives the input voltage for generating the second voltage to the switching circuit. The fifth resistor is coupled to the sixth resistor and receives the input voltage for generating the third voltage to the switching circuit. The voltage divider does not limit that three voltage division information can be provided. When the motor controller is implemented in the integrated circuit chip, the designer may provide one voltage division information or a plurality of voltage division information to the user for setting the needed parameter(s) based on the package type and the pin count. If the user just needs one voltage division information, the switching circuit may be ignored. That is to say, the voltage divider may generate the first voltage to the analog-to-digital converter. 
     The control unit may further generate a select signal to the switching circuit. The switching circuit may be configured to generate an output voltage to the analog-to-digital converter based on the first voltage, the second voltage, the third voltage, and the select signal. The select signal may be a 2-bit digital signal. For example, when the select signal is equal to 00, the switching circuit selects the first voltage to be the output voltage. When the select signal is equal to 01, the switching circuit selects the second voltage to be the output voltage. When the select signal is equal to 10, the switching circuit selects the third voltage to be the output voltage. The analog-to-digital converter receives the output voltage, so as to generate a digital signal to the control unit. At last, the control unit may set each parameter based on the digital signal. Therefore, both the motor unit and the motor controller may provide a better function and resolution for each parameter. 
     More specifically, when the motor is in an operation mode, the motor controller generates various noises due to the interference caused by the motor. Consequently, both the motor unit and the motor controller may execute a prevention mechanism to avoid misjudging the digital signal. When the voltage of the first terminal or the voltage of the second terminal changes, the waveform of the power supply voltage generates noises. Such noises will transfer to the voltage divider via the voltage converter, resulting that the analog-to-digital converter decodes erroneously. Thus, the control unit may further generate an enable signal to the analog-to-digital converter. The analog-to-digital converter may determine whether or not to stop decoding based on the high/low level of the enable signal. When the power supply voltage is less than a predetermined value, both the motor unit and the motor controller may enable the analog-to-digital converter to stop decoding. When the enable signal is at a high level, the control unit may enable the analog-to-digital converter to decode normally. When the enable signal is at a low level, the control unit may enable the analog-to-digital converter to stop decoding. Furthermore, both the motor unit and the motor controller may set a time interval, such that the analog-to-digital converter stops decoding within the time interval. The counting unit receives a clock signal for generating a time signal to the control unit. The time signal may be indicative of the time interval. For instance, when the voltage of the first terminal or the voltage of the second terminal changes, the counting unit may generate the time interval, thereby enabling the analog-to-digital converter to stop decoding within the time interval. When the motor generates noise, the counting unit may recount. That is to say, when the voltage of the first terminal or the voltage of the second terminal changes, the counting unit may recount. By means of such prevention mechanism, both the motor unit and the motor controller may prevent the analog-to-digital converter from decoding erroneously and increase decoding accuracy of the analog-to-digital converter. 
     These and other objectives of the present invention will no doubt become obvious to those of ordinary skill in the art after reading the following detailed description of the preferred embodiment that is illustrated in the various figures and drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above-mentioned and other objects, features, and advantages of the present invention will become apparent with reference to the following descriptions and the accompanying drawing, wherein: 
         FIG.  1    is a schematic diagram showing a motor unit according to one embodiment of the present invention; 
         FIG.  2    is a schematic diagram showing a driving circuit according to one embodiment of the present invention; and 
         FIG.  3    is a timing chart according to one embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     Preferred embodiments according to the present invention will be described in detail with reference to the drawing. 
       FIG.  1    is a schematic diagram showing a motor unit  1  according to one embodiment of the present invention. The motor unit  1  comprises a motor controller  10  and a voltage divider  20 , where the voltage divider  20  may be a resistive voltage divider. The motor controller  10  may be implemented in an integrated circuit chip while the voltage divider  20  may be implemented on a printed circuit board. The motor controller  10  comprises a driving circuit  100 , a control unit  110 , an analog-to-digital converter  120 , a switching circuit  130 , a voltage converter  140 , and a counting unit  150 . The motor controller  10  receives a power supply voltage VPS, such that the driving circuit  100  is biased at the power supply voltage VPS. The voltage converter  140  converts the power supply voltage VPS into an input voltage VIN, where the control unit  110 , the analog-to-digital converter  120 , the switching circuit  130 , the counting unit  150 , and the voltage divider  20  are biased at the input voltage VIN. That is to say, the motor controller  10  generated the input voltage VIN to the control unit  110 , the analog-to-digital converter  120 , the switching circuit  130 , the counting unit  150 , and the voltage divider  20 . The voltage converter  140  may be a step-down converter, such that the power supply voltage VPS is greater than the input voltage VIN. For example, the power supply voltage VPS may be equal to 12 volts while the input voltage VIN may be equal to 5 volts. Therefore, both the motor unit  1  and the motor controller  10  may be applied to a high-voltage configuration.  FIG.  2    is a schematic diagram showing the driving circuit  100  according to one embodiment of the present invention. Please refer to  FIG.  1    and  FIG.  2    simultaneously. The driving circuit  100  includes a first transistor  101 , a second transistor  102 , a third transistor  103 , a fourth transistor  104 , a first terminal O 1 , and a second terminal O 2  for driving a motor M. The motor M is coupled to the first terminal O 1  and the second terminal O 2 . The driving circuit  100  is configured to supply a coil current to the motor M. The first transistor  101  is coupled to the first terminal O 1  and receives the power supply voltage VPS. The second transistor  102  is coupled to the first terminal O 1  and a third terminal GND. The third transistor  103  is coupled to the second terminal O 2  and receives the power supply voltage VPS. The fourth transistor  104  is coupled to the second terminal O 2  and the third terminal GND. Each of the first transistor  101 , the second transistor  102 , the third transistor  103 , and the fourth transistor  104  may be respectively a p-type MOSFET or an n-type MOSFET. As shown in  FIG.  2   , each of the first transistor  101  and the third transistor  103  may be a p-type MOSFET, while each of the second transistor  102  and the fourth transistor  104  may be an n-type MOSFET. The control unit  110  generates a first control signal C 1 , a second control signal C 2 , a third control signal C 3 , and a fourth control signal C 4  so as to respectively control the ON/OFF states of the first transistor  101 , the second transistor  102 , the third transistor  103 , and the fourth transistor  104 . 
     The control unit  110  may operate alternatively in a first driving mode and a second driving mode, so as to supply the electric energy to the motor M. In the first driving mode, the control unit  110  turns on the first transistor  101  and the fourth transistor  104  by controlling the first control signal C 1  and the fourth control signal C 4 . At this moment the current flows sequentially through the first transistor  101 , the motor M, the fourth transistor  104 , and the third terminal GND for supplying the electric energy to the motor M. In the second driving mode, the control unit  110  turns on the second transistor  102  and the third transistor  103  by controlling the second control signal C 2  and the third control signal C 3 . At this moment the current flows sequentially through the third transistor  103 , the motor M, the second transistor  102 , and the third terminal GND for supplying the electric energy to the motor M. By operating alternatively between the first driving mode and the second driving mode, the motor M can be operated normally as a result. 
     By installing the voltage divider  20 , the motor unit  1  may increase the function and the resolution of the pin. The voltage divider  20  receives the input voltage VIN, so as to generate a first voltage V 1 , a second voltage V 2 , and a third voltage V 3 . The voltage divider  20  may comprise a first resistor R 1 , a second resistor R 2 , a third resistor R 3 , a fourth resistor R 4 , a fifth resistor R 5 , and a sixth resistor R 6 . The first resistor R 1  is coupled to the second resistor R 2  and receives the input voltage VIN for generating the first voltage V 1  to the switching circuit  130 . The third resistor R 3  is coupled to the fourth resistor R 4  and receives the input voltage VIN for generating the second voltage V 2  to the switching circuit  130 . The fifth resistor R 5  is coupled to the sixth resistor R 6  and receives the input voltage VIN for generating the third voltage V 3  to the switching circuit  130 . For instance, the first voltage V 1  may be used to set a minimum motor speed, an intermediate value of a motor speed, a minimum input duty cycle, a minimum output duty cycle, a maximum output duty cycle, an intermediate value of an output duty cycle, leading angle information, soft switching information, soft start information, or current limit information. Similarly, the second voltage V 2  may be used to set a minimum motor speed, an intermediate value of a motor speed, a minimum input duty cycle, a minimum output duty cycle, a maximum output duty cycle, an intermediate value of an output duty cycle, leading angle information, soft switching information, soft start information, or current limit information. The third voltage V 3  may be used to set a minimum motor speed, an intermediate value of a motor speed, a minimum input duty cycle, a minimum output duty cycle, a maximum output duty cycle, an intermediate value of an output duty cycle, leading angle information, soft switching information, soft start information, or current limit information. Thus, the voltage divider  20  of the present invention does not limit that three voltage division information can be provided. When the motor controller  10  is implemented in the integrated circuit chip, the designer may provide one voltage division information or a plurality of voltage division information to the user for setting the needed parameter(s) based on the package type and the pin count. If the user just needs one voltage division information, the switching circuit  130  of the present invention may be ignored. That is to say, the voltage divider  20  may generate the first voltage V 1  to the analog-to-digital converter  120 . Moreover, when the motor controller  10  is implemented in the integrated circuit chip, the first voltage V 1  may correspond to a first voltage pin. The second voltage V 2  may correspond to a second voltage pin. The third voltage V 3  may correspond to a third voltage pin. The power supply voltage VPS may correspond to a power supply voltage pin. The input voltage VIN may correspond to an input voltage pin. The first terminal O 1  may correspond to a first terminal pin. The second terminal O 2  may correspond to a second terminal pin. 
     The control unit  110  may further generate a select signal SEL to the switching circuit  130 . The switching circuit  130  may be configured to generate an output voltage VO to the analog-to-digital converter  120  based on the first voltage V 1 , the second voltage V 2 , the third voltage V 3 , and the select signal SEL. The select signal SEL may be a 2-bit digital signal. For example, when the select signal SEL is equal to 00, the switching circuit  130  selects the first voltage V 1  to be the output voltage VO. When the select signal SEL is equal to 01, the switching circuit  130  selects the second voltage V 2  to be the output voltage VO. When the select signal SEL is equal to 10, the switching circuit  130  selects the third voltage V 3  to be the output voltage VO. The analog-to-digital converter  120  receives the output voltage VO, so as to generate a digital signal VD to the control unit  110 . At last, the control unit  110  may set each parameter based on the digital signal VD. According to one preferred embodiment of the present invention, the analog-to-digital converter  120  may be an 8-bit analog-to-digital converter and the analog-to-digital converter  120  may be a SAR (Successive Approximation Register) analog-to-digital converter. Therefore, both the motor unit  1  and the motor controller  10  may provide a better function and resolution for each parameter. 
     More specifically, when the motor M is in an operation mode, the motor controller  10  generates various noises due to the interference caused by the motor M. Consequently, both the motor unit  1  and the motor controller  10  may execute a prevention mechanism to avoid misjudging the digital signal VD.  FIG.  3    is a timing chart according to one embodiment of the present invention. When the voltage of the first terminal O 1  or the voltage of the second terminal O 2  changes, the waveform of the power supply voltage VPS generates noises. Such noises will transfer to the voltage divider  20  via the voltage converter  140 , resulting that the analog-to-digital converter  120  decodes erroneously. Thus, the control unit  110  may further generate an enable signal EN to the analog-to-digital converter  120 . The analog-to-digital converter  120  may determine whether or not to stop decoding based on the high/low level of the enable signal EN. When the power supply voltage VPS is less than a predetermined value, both the motor unit  1  and the motor controller  10  may enable the analog-to-digital converter  120  to stop decoding. When the enable signal EN is at a high level, the control unit  110  may enable the analog-to-digital converter  120  to decode normally. When the enable signal EN is at a low level, the control unit  110  may enable the analog-to-digital converter  120  to stop decoding. Furthermore, both the motor unit  1  and the motor controller  10  may set a time interval T, such that the analog-to-digital converter  120  stops decoding within the time interval T. The time interval T may be a predetermined value and the time interval T may be obtained by the experiment. According to one preferred embodiment of the present invention, the time interval T may be greater than 1 microsecond. The counting unit  150  receives a clock signal CLK for generating a time signal VT to the control unit  110 . The time signal VT may be indicative of the time interval T. For instance, when the voltage of the first terminal O 1  or the voltage of the second terminal O 2  changes, the counting unit  150  may generate the time interval T, thereby enabling the analog-to-digital converter  120  to stop decoding within the time interval T. When the motor M generates noise, the counting unit  150  may recount. That is to say, when the voltage of the first terminal O 1  or the voltage of the second terminal O 2  changes, the counting unit  150  may recount. By means of such prevention mechanism, both the motor unit  1  and the motor controller  10  may prevent the analog-to-digital converter  120  from decoding erroneously and increase decoding accuracy of the analog-to-digital converter  120 . 
     According to one embodiment of the present invention, both the motor unit  1  and the motor controller  10  may be applied to a single-phase motor system, a polyphase motor system, a sensorless motor system, a DC motor system, and a brushless motor system. Both the motor unit  1  and the motor controller  10  may provide a better function and resolution for each parameter. When the motor controller  10  is applied to a high-voltage configuration, the motor M results in more noise. Therefore, when the motor unit  1  and the motor controller  10  are applied to a high-voltage configuration, the motor unit  1  and the motor controller  10  may prevent the analog-to-digital converter  120  from decoding erroneously and increase decoding accuracy of the analog-to-digital converter  120  based on a prevention mechanism. 
     While the present invention has been described by the preferred embodiment, it is to be understood that the invention is not limited to the disclosed embodiment. On the contrary, it is intended to cover various modifications. Therefore, the scope of the appended claims should be accorded the broadest interpretation so as to encompass all such modifications. 
     Those skilled in the art will readily observe that numerous modifications and alterations of the device and method may be made while retaining the teachings of the invention. Accordingly, the above disclosure should be construed as limited only by the metes and bounds of the appended claims.