MP9518

–SINGLE-PHASE, BLDC, MOTOR DRIVER WITH INTEGRATED HALL SENSOR

MP9518 Rev.1.0

www.MonolithicPower.com

10

7/24/2017

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© 2017 MPS. All Rights Reserved.

To spin-up the fan driver softly during start-up,

the current limit increases from 0 to 860mA in

16 steps (see Figure 3). Each step limit value

lasts for 16 internal hall cycles. In rotor lock

fault cases, the current limit increases with 16

steps with 600ms of detection time.

PWM

Current Limit

FG

Figure 3: Start-Up Waveforms

Thermal Shutdown

Thermal monitoring is also integrated into the

MP9518. If the die temperature rises above

150°C, the MOSFETs of the switching half-

bridge turn off. Once the die temperature has

fallen to a safe level, operation resumes

automatically.

Under-Voltage Lockout (UVLO)

If at any time VCC falls below the under-voltage

lockout threshold (UVLO) voltage, all circuitry in

the device is disabled, and the internal logic is

reset. Operation resumes when VCC rises

above the UVLO threshold.

Rotor Deadlock Protection (RD)

The MP9518 detects the internal hall signal and

outputs a deadlock indication signal to FG/RD if

the FGRD bit is set to 11. If the IC cannot see

the hall signal edge change during the 0.6s

detection time, all MOSFETs of the H-bridge

are turned off. FG/RD is an open-drain output.

After 3.6s of recovery time, the IC attempts to

start up again automatically. FG/RD is pulled

low again only after three hall signal edges are

detected after the rotor lock

condition is

released (see Figure 4).

FG

IO

0.6s

3s

0.6s

3s

Rotor Lock

Lock Release

Figure 4: Rotor Deadlock Protection

Rotor Speed Indication (FG)

The MP9518 outputs a hall detection signal to

FG/RD as speed indication. The output signal

frequency can be the same as the internal hall

sensor output frequency. FG/RD is an open-

drain,

so

it

needs

a

pull-up

resistor

in

application.

Over-Voltage Protection (OVP)

If VCC exceeds the over-voltage threshold

(19V), the IC turns off the H-bridge MOSFETs

until VCC drops. Then the IC resumes normal

operation.

Input Reverse Connection Protection

If the input line is reverse-connected to VCC

and GND, the IC detects such fault conditions

automatically and shuts down to avoid damage.