MP6546

– 22V, 3A PEAK, 3-PHASE BLDC DRIVER WITH 1MHZ I2C INTERFACE

MP6546 Rev. 1.0

MonolithicPower.com

11

3/20/2023

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© 2023 MPS. All Rights Reserved.

OPERATION

The MP6546 is a 3-phase brushless DC (BLDC)

motor driver that can support both linear Hall

sensor inputs and a magnetic sensor input. The

device supports multi-slave mode and three-axis

gimbals connected to a single I2C interface bus

to reduce the microcontroller (MCU) load and

system cost. Each slave unit calculates its own

angle and controls the motor based on the

UD[7:0] and UQ[7:0] bits from th

e system’s MCU

via the I2C interface.

External Angle Input Interface

The MP6546 supports both linear Hall inputs and

a magnetic Hall sensor input for the field-

oriented control (FOC) engine and system

control. Use the AMOD bit in register 00h to

select the input interface. The external sensor

angle can be read via the ANGLE[14:0] bits in

register 0Ch.

Magnetic Angle Sensor Input Mode

In magnetic angle sensor input mode, the

MP6546 reads the external angle data input

through the serial peripheral interface (SPI) or

synchronous

serial

communication

(SSC)

interface

(see

Figure

4).

Select

the

communication mode via the SPI_3 bit in register

00h. The baud rate of either interface can be set

via the SPI_BAUD[2:0] bits in register 03h.

Sensor w/ SPI

CS1

SCK1

MISO1

MP6546

CS

SCLK

MISO

MOSI1

MOSI

3.3V

VDD

Sensor w/ SSC

CS1

SCK1

MOSI1

MP6546

CS

CLK

DATA

3.3V

VDD

Figure 4: SPI and SSC Interface

The MP6546 supports the magnetic angle

sensor ICs from MPS

’s MagAlpha family, though

other angle sensors can be applied if the

protocols are compatible. Follow the examples

below to configure the MagAlpha family:

1. Read angle: Set SPI_REG_ADDR[4:0] to 0

and set CMD_CODE[2:0] to 0 by writing to

register 11h. Then the sensor angle

’s value

can be obtained via ANGLE[14:0].

2. Read register: Set SPI_REG_ADDR[4:0] to

the sensor

’s register address, and set

CMD_CODE[2:0] to 1 by writing to register

11h. Then the sensor

’s register value can be

obtained via SPI_DATA[7:0] in register 11h.

3. Write register: Set SPI_REG_ADDR[4:0] to

the

sensor

’s

register

address,

set

SPI_DATA[7:0] to the sensor

’s register

value, and set CMD_CODE[2:0] to 2.

Linear Hall Sensor Input

In linear Hall sensor input mode, the MP6546

reads the external angle data input through the

HA and HB interface. The HA and HB signals go

to the internal analog-to-digital converter (ADC),

and the digital core calculates the angle based

on these two signals (see Figure 5).

Hall Sensor A

HA

MP6546

OUT

Hall Sensor A

HB

OUT

VCC

VCC

VCC

Figure 5: Linear Hall Sensor Interface

To use the linear Hall sensor, set AMOD to 1 to

power up the ADC circuit. Then configure

VA_BIAS[7:0] and VB_BIAS[7:0] (in register

01h) to compensate for the DC offset of the input

SIN/COS signal (VOFFSET). Vx_BIAS[7:0] can be

calculated with Equation (1):

6.445

500

V

0]

:

Vx_BIAS[7

OFFSET −

=

(1)

For example, if VOFFSET is 1650mV, then register

01h should be set to 0xB2B2.