DB62

DB62 Datasheet

DB62

Part	Datasheet
DB62	DB62 (pdf)

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MICROTECHNOLOGY DB62 INTRODUCTION The DB62 is designed to demonstrate the capabilities of the SA305 as a 3 phase brushless DC motor driver IC. The PWM inputs to the SA305 are controlled by an on-board microcontroller. The EVAL49 board is pre-wired for all required and recommended external components. Please refer to applications note 32 in the Apex catalog for guidance in filter component selection. The 1µF ceramic capacitors supplied with the kit are for high frequency bypassing of the VS and VDD supplies C1, C11, C4 and C7 on the EVAL49 schematic . Two additional 100uF bypass capacitors are provided with the kit for the VS supplies C2 and C12 on the EVAL49 schematic . Please refer to applications note 30 for help with power supply bypassing and other useful information. PWM CONTROL IN DB62 BLDC motors are electronically commutated based on the rotor position. The stator windings are energized in a sequence based upon the combination of three Hall sensor signals which provide the rotor position. In the DB62 the SA305 input PWM control is achieved by means of by an on-board PIC 18F2331 microcontroller. The sequence table for commutation obtained from the motor data sheet is entered in the program memory of the microcontroller. Hall sensors A, B and C are connected to the IC pins of the Input Capture IC module in the PIC18F2331. This module interrupts on every transition on any of the IC pins. Upon interrupt, the interrupt service routine reads all the three inputs and loads the correct sequence for commutation. The following PWM control features are programmed in the MCU provided with the DB62 User Controlled PWM frequency using external potentiom- eter VFREQ in EVAL 49 board . The PWM frequency can be varied from 4 KHz to 118 KHz. User Controlled PWM duty cycle using external potentiometer VDUC in EVAL49 board . The voltage set by the potentiometer will act as a ‘Speed Reference’. The duty cycle can be varied from 0 % to 98 The Forward/Reverse button is provided to control the direction of the motor. Depending upon the direction, the corresponding hall sensor commutation sequence is used and the PWM signals are generated accordingly. The START/STOP button can be used to run or stop the motor. As mentioned earlier, the MCU provided with the kit is preprogrammed for all of the features described above. The hall sensor commutation table that has been used in programming the MCU is shown in table HALLA Sensor Output Driver Output HALLB HALLC ØC OUTC ØB OUTB CCW Rotation Facing Lead End CW Rotation Lead End ØA OUTA LO X HI X X HI X LO Table Commutation Table. The algorithm for the microcontroller is shown in figure The program for PIC 18F2331 is available for download on APEX MICROTECHNOLOGY CORPORATION • TELEPHONE 520 690-8600 • FAX 520 888-3329 • ORDERS 520 690-8601 • EMAIL DB62 EVALUATION KIT FOR SA305EX OJUJBMJ[BUJPO %JTBCMF /P 4UBSU :FT OQVUT 3FWFSTF %JSFDUJPO 'PSXBSE PGGTFU 4QFFE 3FGFSFODF 3FDBMDVMBUF 'SFRVFODZ 3FGFSFODF 3FDBMDVMBUF /P 'BVMU :FT Figure 1 Algorithm for PIC 18F2331 MCU as implemented for DB62. APEX MICROTECHNOLOGY CORPORATION • 5980 NORTH SHANNON ROAD • TUCSON, ARIZONA 85741 • USA • APPLICATIONS HOTLINE 1 800 546-2739 EVALUATION KIT FOR SA305EX DB62 SPECIAL CONSIDERATIONS b External RC snubber circuits R13 and C5, R16 and C8, R19 and C10 in EVAL49 schematic can provide noise immunity especially in high load current scenarios. A 100 V 4.7nF capacitor in series with a 50 ohm 5W resistor provided with kit is recommended for the snubber to be connected between each output and PGND. The power dissipated in the snubber components can be estimated by P = V2 • C • FSW Where P is the power dissipated V is the VS supply voltage C is the snubber capacitor value 15nF FSW is the switching frequency.

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MICROTECHNOLOGY

DB62

INTRODUCTION

The DB62 is designed to demonstrate the capabilities of the SA305 as a 3 phase brushless DC motor driver IC. The PWM inputs to the SA305 are controlled by an on-board microcontroller. The EVAL49 board is pre-wired for all required and recommended external components. Please refer to applications note 32 in the Apex catalog for guidance in filter component selection. The 1µF ceramic capacitors supplied with the kit are for high frequency bypassing of the VS and VDD supplies C1, C11, C4 and C7 on the EVAL49 schematic . Two additional 100uF bypass capacitors are provided with the kit for the VS supplies C2 and C12 on the EVAL49 schematic . Please refer to applications note 30 for help with power supply bypassing and other useful information.

PWM CONTROL IN DB62

BLDC motors are electronically commutated based on the rotor position. The stator windings are energized in a sequence based upon the combination of three Hall sensor signals which provide the rotor position. In the DB62 the SA305 input PWM control is achieved by means of by an on-board PIC 18F2331 microcontroller. The sequence table for commutation obtained from the motor data sheet is entered in
the program memory of the microcontroller. Hall sensors A, B and C are connected to the IC pins of the Input Capture IC module in the PIC18F2331. This module interrupts on every transition on any of the IC pins. Upon interrupt, the interrupt service routine reads all the three inputs and loads the correct sequence for commutation. The following PWM control features are programmed in the MCU provided with the DB62 User Controlled PWM frequency using external potentiom-
eter VFREQ in EVAL 49 board . The PWM frequency can be varied from 4 KHz to 118 KHz. User Controlled PWM duty cycle using external potentiometer VDUC in EVAL49 board . The voltage set by the potentiometer will act as a ‘Speed Reference’. The duty cycle can be varied from 0 % to 98 The Forward/Reverse button is provided to control the direction of the motor. Depending upon the direction, the corresponding hall sensor commutation sequence is used and the PWM signals are generated accordingly. The START/STOP button can be used to run or stop the motor. As mentioned earlier, the MCU provided with the kit is preprogrammed for all of the features described above. The hall sensor commutation table that has been used in programming the MCU is shown in table

HALLA

Sensor Output

Driver Output

HALLB

HALLC ØC OUTC ØB OUTB

CCW Rotation Facing Lead End

CW Rotation Lead End
ØA OUTA

LO X HI X

X HI X LO

Table Commutation Table. The algorithm for the microcontroller is shown in figure The program for PIC 18F2331 is available for download on

APEX MICROTECHNOLOGY CORPORATION
• TELEPHONE 520 690-8600
• FAX 520 888-3329
• ORDERS 520 690-8601
• EMAIL

DB62

EVALUATION KIT FOR SA305EX
*OJUJBMJ[BUJPO %JTBCMF
/P 4UBSU :FT
*OQVUT
3FWFSTF
%JSFDUJPO
'PSXBSE

PGGTFU
4QFFE 3FGFSFODF
3FDBMDVMBUF
'SFRVFODZ 3FGFSFODF
3FDBMDVMBUF
/P 'BVMU
:FT Figure 1 Algorithm for PIC 18F2331 MCU as implemented for DB62.

APEX MICROTECHNOLOGY CORPORATION
• 5980 NORTH SHANNON ROAD
• TUCSON, ARIZONA 85741
• USA
• APPLICATIONS HOTLINE 1 800 546-2739

EVALUATION KIT FOR SA305EX

DB62

SPECIAL CONSIDERATIONS
b External RC snubber circuits R13 and C5, R16 and C8, R19 and C10 in EVAL49 schematic can provide noise immunity especially in high load current scenarios. A 100 V 4.7nF capacitor in series with a 50 ohm 5W resistor provided with kit is recommended for the snubber to be connected between each output and PGND.

The power dissipated in the snubber components can be estimated by P = V2
• C
• FSW Where P is the power dissipated V is the VS supply voltage C is the snubber capacitor value 15nF FSW is the switching frequency.

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DB62

DB62 Datasheet

Datasheet ID: DB62 523216