MP6510

—4.5V-TO-16V, 1.2A, SINGLE-PHASE, BRUSHLESS DC MOTOR DRIVER

MP6510 Rev.1.01

www.MonolithicPower.com

8

1/16/2018

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

© 2018 MPS. All Rights Reserved.

FUNCTION DESCRIPTION

Motor Driver

The OUT1 and OUT2 pins drive the motor with a

maximum continuous output current of 1.2A at

room temperature. The peak output current value

is proportional to the Hall sensor output voltage

Frequency Setting

A capacitor at the COSC pin sets the frequency.

For most applications, use a 100pF capacitor for

a typical PWM frequency of 30kHz.

Minimum Speed

The voltage on the RMI pin sets the minimum

PWM duty cycle to set the lowest speed.

Connect to VTH if not used.

Locked-Rotor Detection

The locked-rotor detector (the RD pin) is the

output of an open collector. It goes low when the

motor is rotating and goes into high impendence

if the motor is in a locked-rotor state. Leave it

open if not used.

Speed Detection

The rotational speed detector (the FG pin) is the

output of an open collector. It outputs a high or

low voltage relative to the Hall

comparator’s

output. Higher speeds produce higher-frequency

signals. Leave it open if not used.

Current Limit Proportional to Hall Signal

An internal amplifier with hysteresis amplifies the

differential Hall signal: The output of this amplifier

serves as the current limit value. The differential

Hall voltage drops to 0V every time an opposing

magnet passes the Hall sensor, which limits the

peak current during commutation. The Hall

sensor is directly powered by a 1.2V voltage on

the HB pin. In order to prevent the possible large

current during startup or lock-rotor period, an

internal secondary current limit is employed. It

ensures the current less than 2.5A typically. The

Hall senor input sensitivity accepted by the part is

down to 3mV.

Input OVP

A

reverse

current

generated

with

every

commutation charges the input capacitor and

causes a periodic voltage spike on the input pin.

The internal input over-voltage protection (OVP)

circuit turns off two HS switches when a spike

exceeds 20V, and recovers from OVP when the

spike is less than 18V.

Over Temperature Protection

The MOSFET is shutdown when the temperature

exceeds about 175

the temperature is below about 155

Working Mode

The driver has 4 modes under normal conditions

as shown in Figure 2. The following describes

each mode:

 Minimum Speed Mode

This mode runs the motor at the slowest

motor speed. It uses a thermistor to provide

the VTH signal and compares it with RMI to

determine the slowest motor speed.

At low temperatures, VTH exceeds RMI. The

device

compares

the motor speed. Removing the thermistor

causes VTH and the motor speed to reach

their respective maxima and minima.

 Variable Speed Mode

When the VTH signal falls below RMI, the

the motor speed. In general, VTH controls the

PWM duty cycle, and therefore the motor

speed.

 Full-Speed Mode

the PWM duty is 100% and the motor speed

is at its maximum.

 Locked-Rotor Protection

capacitor at the CT pin; changing the Hall

comparator’s output provides a reset signal to

drive an internal switch to discharge this

If

the

motor

rotor

is

locked,

the

Hall

comparator’s output will not change. Once

driver enters locked-rotor protection mode

the CT capacitor. During this period, the

PWM duty cycle goes to 0% and the RD pin

is in a high impedance state. When the