SI9979_04 Datasheet, PDF (6/9 Pages) Vishay Siliconix – 3-Phase Brushless DC Motor Controller

Si9979
Vishay Siliconix
PIN DESCRIPTION (CONT’D)
Pin 34: GT_A
This is the gate drive output for the top MOSFET in Phase A.
Pin 35: S_A
This pin is negative supply of the high-side drive circuitry. As
such, it is the connection for the negative side of the bootstrap
capacitor, the top MOSFET Source, the bottom MOSFET
Drain, and the Phase A output.
Pin 36: CAP_A
This pin is the positive supply of the high-side circuitry. The
bootstrap capacitor for Phase A is connected between this pin
and SA.
Pin 42: V+
The supply voltage for the Si9979 is connected between this
pin and ground. The internal logic and high-side supply
voltages are derived from V+.
Pin 43: V_DD
V_DD is the internal logic and gate drive voltage. It is necessary
to connect a capacitor between this pin and ground to insure
that the current surges seen at the turn on of the bottom
MOSFETs does not trip the undervoltage lockout circuitry.
APPLICATION CIRCUITS
V+
1 mF
To
Commutation
Sensors
TACH
PWM IN
FAULT
GND
R_T
C_T
Si9979
42 _V+
43 _VDD
1 _INA
2 _INB
3 _INC
5 _EN
6 _F/R
9 _BRK
4 _60/120
10 _TACH
7 _QS
8
11
PWM
18 ^FAULT
17
R_T
R_T/C_T
GND
GT_A ³⁴
S_A ³⁵
CAP_A ³⁶
GT_B ³⁰
S_B ³¹
CAP_B ³²
GT_C ²⁶
S_C ²⁷
CAP_C ²⁸
GB_A ³⁵
GB_B ²⁹
GB_C ²⁵
I_S+ ¹⁹
I_S− ²⁰
GND
12−16, 21−24
37−41, 44−48
CB_A
CB_B
CB_C
R
C
R_S
LITTLE FOOT
Q1
Q2
Q4
Q5
Q3
A
B To
Motor
C _Windings
Q6
www.vishay.com
6
FIGURE 1. Three-Phase Brushless DC Motor Controller
Document Number: 70012
S-41209—Rev. E, 21-Jun-04