ls7262 LSI Computer Systems, Inc., ls7262 Datasheet - Page 6

• Manufacturer Part Number: ls7262
• Description: Brushless Dc Motor Commutator/controller
• Manufacturer: LSI Computer Systems, Inc.

For controlled acceleration and deceleration of motors in the forward or reverse directions, a motor control pulse width modulator circuit such
as the SG1731 or UC1637 can be interfaced with the LS7262.
The logical OR gate made up of the resistor-diode network permits the LS7262 to be enabled when either the forward or reverse input is high.
By applying the forward input directly to Pin 19, the motor can only operate in the forward direction when the forward input is high and only in
the reverse direction when the reverse input is high. Motor direction is determined by relative pulse widths of the forward and reverse inputs
while acceleration or deceleration is determined by variations of these widths.
For four phase commutation (See Fig.4), the COMMUTATION SELECT inputs must both be tied low. The S1 input is driven from one motor
position sensor while the S2 and S3 inputs are connected together and driven by the second position sensor. The COMMON input must be
connected to VSS. The sensors have an electrical separation of 90°. Figure 4A indicates the use of Bipolar Transistors. Figure 4B indicates
the use of FETs.
7262-051711-6
FIGURE 3. PRECISION CONTROL BRUSHLESS DC MOTOR DRIVE
OUTPUT COMMUTATION SEQUENCE FOR FOUR PHASE OPERATION
S1 S2,S3 FWD/REV=1 FWD/REV=0
0
1
1
0
CS1=CS2=0 OUTPUTS ENABLED
0
0
1
1
TABLE 4.
O1
O3
O4
O6
O4
O6
O1
O3