MA120 – ANGULAR SENSOR FOR BRUSHLESS MOTOR COMMUTATION

PRELIMINARY SPECIFICATIONS SUBJECT TO CHANGE

MA120 Rev. 1.2

www.MonolithicPower.com

13

7/25/2016

MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited.

Preliminary Specifications Subject to Change

© 2016 MPS. All Rights Reserved.

Figure 7: Timing Diagram for Simple SPI Readout

A full reading requires 8 clock pulses. The

MA120 delivers:

MSB

LSB

A(7:0)

If the master triggers the reading faster than the

refresh rate, the MagAlpha may send the same

sample several times.

Block Commutation - UVW

The UVW output emulates the three Hall

switches

usually

used

for

the

block

commutation of the 3-phase electric motor. The

three logic signals have a duty cycle of ½ and

are shifted by 60 deg relative to each other (see

Figure 8).

Figure 8: UVW Output during Rotation

One-Time

Programmable

(OTP)

Programming

The one-time programmable (OTP) memory

can permanently store the content of the

programmable registers. The OTP memory is

made of poly-silicon fuses. By activating the

flash command, the content of an entire register

can be stored in the OTP memory. The flash

command consists of setting some bits (Fn,

where n is the register number) in register 9.

For flashing the register, when the bit Fn is set,

the register n is stored permanently. It is

important to note that only one register can be

flashed at a time. It is possible to operate the

MagAlpha without flashing the registers (see

Figure 9).

Figure 9: Circuit for Flashing

Burning the fuses during the flash process is

irreversible. Once a register is flashed, the

default values at power-up are always the

same. After flashing, the content of the registers

can no longer be modified.