7260-110515-1

BRUSHLESS DC MOTOR COMMUTATOR / CONTROLLER

LS7260

LS7262

FEATURES:

Direct drive of P-Channel and N-Channel FETs (LS7260)

Direct drive of PNP and NPN transistors (LS7262)

Six outputs drive power switching bridge directly

Open or closed loop motor speed control

Externally selectable input to output code for 60°,

120°, 240°, or 300° electrical sensor spacing

Three or four phase operation

Analog speed control

Direction control

Output enable control

Positive static braking

Over-current sensing

LS7260, LS7262 (DIP); LS7260-S, LS7262-S (SOIC);

LS7260-TS, LS7262-TS (TSSOP) – See Connection Diagram.

PIN ASSIGNMENT – TOP VIEW

DESCRIPTION:

The LS7260 / LS7262 are MOS integrated circuits designed to

generate the signals necessary to control a three phase or four

phase brushless DC motor. They are the basic building blocks of a

brushless DC motor controller. The circuits respond to changes at

the SENSE inputs, originating at the motor position sensors, to

provide electronic commutation of the motor windings. Pulse width

modulation of outputs for motor speed control is accomplished

through either the ENABLE input or through the analog input

(VTRIP) in conjunction with the OSCILLATOR input. Over-current

circuitry is provided to protect the windings, associated drivers, and

power supply. The over-current circuitry causes the external output

drivers to switch off immediately upon sensing the over-current

condition and on again only when the over-current condition

disappears and the positive edge of either the ENABLE input or the

saw-tooth OSCILLATOR occurs. This limits the over-current sense

cycling to the chopping rate of the ENABLE input or the saw-tooth

OSCILLATOR.

A positive braking feature is provided to effect rapid deceleration.

While the LS7262 is designed for driving PNP and NPN transistors

(See Fig. 2.), the LS7260 is designed to drive both PMOS and

NMOS Power FETs and develops a full 12V drive for both the N-

Channel and P-Channel devices (See Fig. 1) when using a 12V

power supply.

Nov 2015

INPUT / OUTPUT DESCRIPTION:

COMMUTATION SELECTS (Pins 1, 20)

These inputs are used to select the proper sequence of outputs

based on the electrical separation of the motor position sensors.

See Table 3. Note that in all cases the external output drivers are

disabled for invalid SENSE input codes. Internal pull down resistors

are provided at Pins 1 and 20 causing a logic zero when these pins

are left open.

FORWARD / REVERSE (Pins 19)

These inputs are used to select the proper sequence of outputs for

the desired direction of rotation for the Motor (See Table 3). An

internal pull-up resistor holds the input high when left open.

SENSE INPUTS (Pins 15, 16, 17)

These inputs provide control of the output commutation sequence

as shown in Table 3. S1, S2, S3 originate in the position sensors of

the motor and must sequence in cycle code order. Hall-switch pull-

up resistors are provided at Pins 15, 16 and 17. The positive supply

BRAKE (Pin 9)

For the LS7262 and LS7362, a high level at this input

unconditionally turns off outputs 1, 2 and 3 and turns on outputs 4, 5

and 6 (See Figures 2 and 4.) For the LS7260, a high level at this

input turns on outputs 1, 2 and 3 and outputs 4, 5 and 6 (See Fig.

1). In both cases, transistors Q101, Q102 and Q103 cut off and

transistors Q104, Q105 and Q106 turn on, shorting the windings

together. The BRAKE has priority over all other inputs.