Patent Publication Number: US-10323961-B2

Title: Motor-driven integrated circuit, motor device, and application apparatus

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This non-provisional patent application claims priority under 35 U.S.C. § 119(a) from Patent Application No. 201610978253.5 filed in the People&#39;s Republic of China on Nov. 4, 2016. 
     FIELD OF THE INVENTION 
     This disclosure relates to a field of circuit technology. In particular, the present disclosure relates to a motor driver integrated circuit for driving a motor, a motor device and an application apparatus using same. 
     BACKGROUND OF THE INVENTION 
     In motor control field, a microcontroller can perform different functions. A nonvolatile memory, such as, a Flash memory, can be used to store data in the microcontroller. However, the Flash memory needs a special process manufacturing, a high cost and a long research and development cycle. 
     SUMMARY OF THE INVENTION 
     A motor driver integrated circuit comprises a multiple-time programmable memory to store a motor driver program, a memory having a capacity larger than or equal to a capacity of the multiple-time programmable memory, and a central processing unit. When the motor driver integrated circuit is powered or reset, the central processing unit copies the driven program from the multiple-time programmable memory to the memory. 
     Preferably, the motor driver integrated circuit further comprises a PWM output unit; an overcurrent comparator receiving a detection signal and comparing the detection signal with a reference value; wherein when the detection signal is larger than the reference value, the PWM output unit is entered to an overcurrent protection mode under control an overcurrent protection signal output by the overcurrent comparator. 
     Preferably, the motor driver integrated circuit further comprises a first filter coupled between the PWM output unit and the overcurrent comparator. 
     Preferably, the overcurrent comparator directly outputs the overcurrent protection signal to the PWM output unit and controls the PWM output unit to enter the overcurrent protection mode. 
     Preferably, the overcurrent comparator outputs the overcurrent protection signal to the central processing unit and the central processing unit controls the PWM output unit to enter the overcurrent protection mode. 
     Preferably, the motor driver integrated circuit further comprises an interrupt controller, and the overcurrent comparator outputs the overcurrent protection signal to the interrupt controller, the interrupt controller outputs an interrupt signal to the central processing unit, and the central processing unit controls the PWM output unit enter the overcurrent protection mode. 
     Preferably, when the PWM output unit is entered into the overcurrent protection mode, the PWM output unit performs one of following operations: stopping outputting drive signal; reducing a duty of the drive signal; and stopping outputting the drive signal and resetting to output the drive signal after a preset time delay. 
     Preferably, the motor driver integrated circuit further comprises a plurality of position comparators, each position comparator receives a pole detection signal and outputs a comparison signal to the central processing unit; the central processing unit controls the PWM output unit to output the drive signal. 
     Preferably, the motor driver integrated circuit further comprises a plurality of operation amplifiers, each operation amplifier receives a current flowing through a winding, the central processing unit obtains a rotation speed according to the current. 
     Preferably, the motor driver integrated circuit further comprises a timer, wherein when a jumping edge of a pole detection signal is detected, the position comparator outputs a timing interrupt signal to the timer, a time is recorded by, and a rotation speed is obtained according to a time difference between two adjacent edges. 
     Preferably, the motor driver integrated circuit further comprises a shifter connected to the central processing unit via a bus. 
     A motor device comprises a motor and the motor driver integrated circuit as described-above. 
     An application apparatus comprises a motor device as described-above. 
     Preferably, the application apparatus is one of a pump, a fan, a household appliance, and a vehicle. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       A preferred embodiment of the invention will now be described, by way of example only, with reference to figures of the accompanying drawings. In the figures, identical structures, elements or parts that appear in more than one figure are generally labeled with a same reference numeral in all the figures in which they appear. Dimensions of components and features shown in the figures are generally chosen for convenience and clarity of presentation and are not necessarily shown to scale. The figures are listed below. 
         FIG. 1  shows a block diagram of a motor device according to one embodiment of the present disclosure. 
         FIG. 2  shows a circuit diagram of an inverter and a motor winding of  FIG. 1 . 
         FIG. 3  shows a waveform of a Hall sensor of  FIG. 1 . 
         FIG. 4  shows a block diagram of a CPU of a motor driver integrated circuit is coupled to a timer via a logic selection circuit according to one embodiment. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Hereinafter, particular embodiments of the present disclosure are described in detail in conjunction with the drawings, so that technical solutions and other beneficial effects of the present disclosure are apparent. It can be understood that the drawings are provided only for reference and explanation, and are not used to limit the present disclosure. Dimensions shown in the drawings are only for ease of clear description, but are not limited to a proportional relationship. 
       FIG. 1  shows a motor device  100  according to one embodiment. The motor device  100  can include a motor  30 , a motor driver integrated circuit  10 , and an inverter  20 . In the embodiment, the motor  30  can be a brushless direct current motor (BLDC), or a permanent magnet synchronous motor (PMSM). The motor  30  can include a stator and a rotor rotatably received in the stator. The stator can comprise a stator core and a stator winding wound around on the stator core. The stator core can be made of soft magnetic materials such as pure iron, cast iron, cast steel, electrical steel, silicon steel. The rotor can include a plurality of permanent magnet. 
     In the embodiment, the motor  30  can be a three phase BLDC. The stator core can include three phases labeled as, U, V, and W. One end of the three phases U, V, and W is electrically coupled to the inverter  20 , and the other end of the three phases U, V, and W is electrically coupled to a neutral point. In the embodiment, the stator winding is connected in Y-shaped. In another embodiment, the stator winding can be connected in triangular shaped. 
     In the embodiment, the inverter  20  can be a three-phase bridge inverter. The inverter  20  can include six semiconductor switches. The U phase winding is electrically coupled with a node between an upper side switch UH and a lower side switch UL. The V phase winding is electrically coupled with a node between an upper side switch VH and a lower side switch VL. The W phase winding is electrically coupled with a node between an upper side switch WH and a lower side switch WL. The motor driver integrated circuit  10  outputs a drive signal, such as, a PWM signal, to the inverter  20 . Each switch is controlled by the control signal to switch on and switch off. The two switches in each bridge are interlocked, that is only one switch can be turned on in each bridge. In the embodiment, each switch can be a MOSFET. In another embodiment, each switch can be selected from insulated gatebipolar transistor (IGBT), or BJT. 
     In another embodiment, the motor  30  can be a single phase, two phase or multiple phase BLDC. 
     The motor  30  can further include a position sensor to sense a position of the rotor. In the embodiment, the motor  30  can include three Hall sensors, which are labeled as H 1 , H 2 , and H 3 , respectively. The three Hall sensors H 1 , H 2  and H 3  are arranged at an electrical angle of 120 degrees in the circumferential direction of the rotor. In another embodiment, the three Hall sensors H 1 , H 2 , H 3  may be arranged in turn along the circumferential direction of the rotor at other electrical angles, such as 60 degrees. The Hall sensors H 1 , H 2  and H 3  output logic high or low level pole detection signals according to a direction of magnetic fluxes through the Hall sensors H 1 , H 2  and H 3 , and each edge of the pole detection signal indicates a change of a polarity of the rotor. 
     The motor driver integrated circuit  20  can include a housing, a semiconductor substrate arranged in the housing, a plurality of input and output (I/O) interfaces extending from the housing. The motor driver integrated circuit  20  can include a central processing unit (CPU)  115 , a memory  130 , a Multiple-Time Programmable (MTP) memory  120 , a timer  150 , a shifter  160 , a PWM output unit  125 , an overcurrent comparator  180 , a plurality of position comparators  190 , a plurality of operation amplifiers  195 , a first filter  182 , a second filter  192 , and an Analog-to-Digital Converter (ADC)  170 . The PWM output unit  125 , the overcurrent comparator  180 , the plurality of position comparators  190 , the plurality of amplifiers  195  and the ADC  170  are electrically coupled to the I/O interfaces. In the embodiment, the CPU  115  can be a 8-bit Single Chip Micyoco (SCM), an operating frequency of the SCM can be 80 MHz. 
     The CPU  115  is electrically coupled to the memory  130 , the MTP memory  120 , the shifter  160 , the timer  150 , the PWM output unit  125 , the first filter  182 , the second filter  192 , and the ADC  170  via a bus. 
     The CPU  115  is a central control center of the motor device  100 . The memory  130  can temporarily store operation data of the CPU  115 . The MTP memory  120  can store a configuration data of the motor device  100  and a plurality of driven programs of the motor device  100 . 
     The motor driver integrated circuit  20  can include three position comparators  190 . Each position comparator can receives a pole detection signal which denotes a position of the rotor. Each position comparator can compare the pole detection signal with a reference value and output a comparison result signal. Output ends of the three position comparators  190  are electrically coupled to the CPU  115  via the second filter  192 . The rotor pole position is obtained by the CPU  115  according to the pole detection signals output by the three Hall sensors. In the embodiment, the pole detection signals are denoted as  011 ,  001 ,  101 ,  100 ,  110 , and  010  between a 360 degrees electrical cycle. The CPU  115  controls the PWM output unit  125  output the drive signal to drive the motor  30 . When the three pole detection signals are  011 , the CPU  115  controls the PWM output unit  125  output the drive signal to turn on the upper side switch UH and the lower side switch WL. In the embodiment, the pled detection signals are square wave. 
     In another embodiment, the position sensors can be omitted. The CPU can obtain the rotor position via a sensorless method. When the motor  30  rotates, a back electromotive force is generated in the stator winding. The rotor position can be obtained by detecting a zero crossing of the back electromotive force with the position comparators  190 . 
     The plurality of operation amplifiers  195  can be used in Field Oriented Control (FOC) of PMSM. In the embodiment, the plurality of operation amplifiers  195  simultaneously collect currents of the two-phase windings in the three-phase windings and then amplifies them to the analog-to-digital converter  170 , and calculates the other phase according to the result of the conversion. And the central processing unit  115  obtains a rotation speed of the motor by Park positive and negative transformation based on the currents of each phase winding. In the embodiment, the current acquired by the operation amplifier  195  is a sine wave, and it is understood that the current acquired by the operation amplifier  195  may be other waveforms. 
     Output ends of the plurality of operation amplifiers  195  are electrically coupled to the analog-to-digital converter  170 . The analog-to-digital converter  170  can include a sample and hold circuit  172  and an analog-to-digital unit  174 . The analog-to-digital unit  174  can convert an analog signal output by the operation amplifier  195  to a digital signal. The sample and hold  172  is configured to ensure an accuracy of the analog-to-digital unit  174 . 
     The PWM output unit  125  can include a plurality of output ends. In the embodiment the PWM output unit  125  can include six output ends. Each output end is electrically coupled to one semiconductor switch of the inverter  20 . The PWM output unit  125  is controlled by the CPU  115  to output drive signals to turn on and off the semiconductor switch of the inverter  20 . 
     One input end of the overcurrent comparator  180  receives a detection signal which denotes an operation current of the motor  30 , the other input end of the overcurrent comparator  180  receives a reference value VREF. An output end of the overcurrent comparator  180  is electrically coupled to the PWM output unit  125  and the CPU  115  via the first filter  182 . 
     An 8-bit microcontroller is usually operated in a low frequency, such as 20-50 MHz. The 8-bit microcontroller with low frequency cannot meet the real-time requirements for the motor control, and the real-time motor drive chip is usually used at least 16-bit microcontroller with a higher cost. In the embodiment, the motor driver integrated circuit is fabricated using a 0.15 μm semiconductor process with a higher operating frequency (e.g., 80 MHz), which can improve the processing speed and meet the real-time requirements for motor control. On the other hand, the 8-bit microcontroller can significantly reduce cost, and 0.15 μm process can reduce a size of bare die to 8˜9 mm 2 . In contrast, if the 0.25 μm process, the operating frequency is less than 50 MHz, the 0.35 μm process, the clock frequency is 20·30 MHz, and die area will increase proportionally. 
     When the motor device  100  is powered or reset, the CPU  115  firstly performs a boot loader program, and copy all program codes from the Multiple-Time Programmable memory  120  memory  120  to the memory  130 . The Multiple-Time Programmable memory  120  stores motor configuration data and motor driver programs. In the embodiment, he configuration data and the motor driver programs can be stored in the Multiple-Time Programmable memory  120 . Compared with Flash memory, in particular to large-scale manufacturing, the Multiple-Time Programmable memory  120  can reduce cost. In the embodiment, a capacity of the Multiple-Time Programmable memory  120  is 32 KB. In another embodiment, the capacity of the Multiple-Time Programmable Memory  120  can be 48 KB, 64 KB. A capacity of the memory  130  is 48 KB, the capacity of the memory  130  is larger than the capacity of the Multiple-Time Programmable memory  120 . In the embodiment, the memory  130  can be a random access memory (RAM). As the memory  130  has a higher operating frequency than the Multiple-Time Programmable memory  120 , all program codes in the MTP  130  are copied to the memory, the motor driver integrated circuit  10  accelerates operating frequency with a low cost. 
     The Hall sensors H 1 , H 2 , and H 3  output three pole detection signals to the three position comparators  190 , respectively. As shown in  FIG. 3 , the three pole detection signals are mutually different with 120 degree electrical angle. When the position comparator  190  obtains a level transition of the pole detection signal, that is a rising edge or a falling edge, the position comparator  190  outputs a timing interrupt signal to the timer  150 . 
     A first position comparator obtains a rising edge H 1   a , and the first position comparator outputs a timing interrupt signal to the timer  150  and the timer  150  records a time t0. When a next edge is generated, such as a falling edge H 3   b , the third position comparator outputs a timing interrupt signal to the timer  150  and the timer  150  records a time t1. The CPU  115  obtains a rotation speed of the motor  30  via a time difference Δt between t0 and t1. 
     After the time t1 is recorded, the timer  150  clears the time t0 and records time t1 as time t0. When a next edge is generated, such a rising edge H 2   a , the second comparator outputs a timing interrupt signal to the timer  150 . The CPU  115  obtains a rotation speed of the motor via a time difference Δt between t0 and t1. And then the rotation speed of the motor is obtained by calculating the time difference between the rising edge H 2   a  and the falling edge H 1   b  as follows. In the motor running stage, the CPU  115  determines the operating condition of the motor by calculating the rotational speed of the motor by the time difference of every two adjacent edges. 
     In the embodiment, it is possible to detect not only the time difference of adjacent edges but also the time difference at which the adjacent edge or adjacent rising and falling edges of the Hall signal can be detected as necessary. In another embodiment, the position comparator  190  are electrically connected to a logic selection circuit  193  which is coupled to the central processing unit  115  and the timer  150 . The logic selection circuit  193  selects two adjacent edge of one Hall signal, the two adjacent rising edges of one Hall signal, the two adjacent falling edges of the one Hall signal, the two adjacent edges of two Hall signals, the two adjacent rising edges of two Hall signals, or the two adjacent falling edge of two Hall signals according to a setting of the central processing unit  115 . The timer  150  is controlled to time according to the two edges selected by the logic selection circuit  193 . 
     Each position comparator is needed to connect an interrupt controller. In the embodiment, the position comparators  190  are directly coupled to the timer  150  or coupled to the timer  150  via the logic selection circuit  193 . The interrupt controller can be omitted. And the timer  150  counts in response to the edge of each Hall signal, a sampling frequency is fast. It is obvious that a faster sampling, a better dynamic response can be obtained. The motor can operate more smoothly and reduce a speed fluctuation. The logic selection circuit is provided in the motor driver integrated circuit  10 , it is possible to select the different edges to calculate the rotation speed of the motor so that the motor driver integrated circuit  10  can be adapted to different motor devices to improve the versatility of the motor. 
     The motor driver integrated circuit  10  can further include a shifter  160 . In the embodiment, the shifter  160  can be a barrel shifter. The shifter  160  can perform a shift operation bits in a plurality of ways such as multiplication and division in a single cycle. For example, if all the operations are performed by the CPU  115 , the operation of the system will be slowed down, and the operation such as multiplication and division is performed by the shifter  160 , and the shift operation becomes faster, And the shift operation is not performed by the CPU  115 , the CPU  115  can be released for performing other operation, and an efficiency of the entire motor driver integrated circuit  10  can be increased. 
     During the operation of the motor, the overcurrent comparator  180  receives a detection signal indicative of the operating current of the motor. In the embodiment, a sampling resistor R is coupled the inverter  20  and a ground. The operating current of the motor is converted into a sampling voltage by the sampling resistor R. The overcurrent comparator  180  receives the sampling voltage and compares the sampling voltage with the reference value VREF. When the sampling voltage is larger than the reference value VREF, the overcurrent is generated in the motor, and the overcurrent comparator  180  outputs an overcurrent protection signal to the PWM output unit  125 . The PWM output unit  125  can enter an overcurrent protection mode according to the overcurrent protection signal. In this way, the overcurrent comparator  180  directly controls the PWM output unit  125  to enter the overcurrent protection mode when the overcurrent is generated in the motor, and the PWM output unit  125  responds quickly to the overcurrent of the motor and can protect the motor quickly and efficiently. In another embodiment, the overcurrent comparator  180  outputs the overcurrent protection signal to the central processing unit  115 , and then the central processing unit  115  controls the PWM output unit  125  to enter the overcurrent protection mode. 
     When the PWM output unit  125  enters the overcurrent protection mode, the PWM output unit  125  may perform one of the following operations, for example, to stop outputting the drive signal to the inverter  20 , to reduce a duty of the drive signal output to the inverter  20 , to stop outputting the drive signal to the inverter  20  and reset to output the drive signal after a preset time delay. The specific operation in the overcurrent protection mode can be performed according to the design requirements or the environment of the motor application. 
     The first filter  182  is coupled between the overcurrent comparator  180 , the PWM output unit  125  and the central processor  115 . The first filter  182  may be configured to sample the overcurrent protection signal in a predetermined manner. The predetermined manner can be that the first filter  182  samples the overcurrent protection signal for a predetermined number of times in a predetermined cycle, the first filter  182  samples the overcurrent protection signal in two cycles. The first filter  182  determines whether the overcurrent is generated according to sample values. The first filter  182  is configured to eliminate a glitch signal. The second filter  192  has a similar function and will not be described again. In the embodiment, the first filter  182  and the second filter  192  are Glitch Filter. 
     In another embodiment, the motor driver integrated circuit  10  can include an interrupt controller  140 . When the overcurrent is generated in the motor, the overcurrent comparator simultaneously outputs the overcurrent protection signal to the interrupt controller  140  and the PWM output unit  125 . The interrupt controller  140  sends an interrupt signal to the CPU  115 , which controls an external device, such as a display, an alarm, etc., to indicate that the motor  30  is in a fault condition based on the interrupt signal. 
     In the embodiment, the overcurrent comparator  180  is integrated in the motor driver integrated circuit  10 , which reduces a number of electronic components used compared to the prior art and reduces an overall size of the motor control circuit. The motor driver integrated circuit can run with a low power consumption and a high reliability. 
     The motor device  100  according to the embodiment can also be applied to an application device, which may be one of a pump, a fan, a household appliance, a vehicle, etc. The household appliance can be a washing machine, a dishwasher, a rangehood, an exhaust fan and so on. 
     In the description and claims of the present application, each of the verbs “comprise”, “include”, “contain” and “have”, and variations thereof, are used in an inclusive sense, to specify the presence of the stated item or feature but do not preclude the presence of additional items or features. 
     It is appreciated that certain features of the invention, which are, for clarity, described in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features of the invention which are, for brevity, described in the context of a single embodiment, may also be provided separately or in any suitable sub-combination. 
     The embodiments described above are provided by way of example only, and various other modifications will be apparent to persons skilled in the field without departing from the scope of the invention as defined by the appended claims.