MP6619

– 5.4V TO 28V, 5A, H-BRIDGE MOTOR DRIVER

MP6619 Rev. 1.0

www.MonolithicPower.com

8

1/21/2021

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© 2021 MPS. All Rights Reserved.

OPERATION

The MP6619 is an H-bridge motor driver that

operates from a supply voltage up to 28V and

delivers a motor current up to 5A. Typically, the

MP6619 is used to drive a brushed DC motor.

Input Logic

For the MP6619, control of each half-bridge is

independent, using EN, IN1, and/or IN2 (see

Table 1).

Table 1: Truth Table

EN

INx

OUTx

0

x

Z

1

0

L

1

1

H

Shutdown Mode

If the EN signal is pulled low, the MP6619 shuts

down. In shutdown mode, all circuits and blocks

are disabled, and the MP6619 consumes less

than 1µA of shutdown current. There is about

150ns of deglitch time on EN to avoid a

mistrigger.

Current Limit

The MP6619 has a programmable current limit

function. The output current flowing through

both two low-side MOSFETs is sensed by an

external sense resistor. If the load current

reaches the current trip threshold, a current limit

condition is triggered, the entire

H-bridge

switches to a high-impedance state with all

MOSFETs turned off. After a fixed off time

(tITRIP), the MOSFETs are re-enabled, and the

cycle repeats.

The current limit is triggered when the IFB pin

voltage (VIFB) reaches the current trip voltage

(VITRIP). For example, if a 40mΩ sense resistor

is connected from LSS to ground, and the

current trip voltage (VITRIP) is 200mV, when the

output current reaches 5A, VIFB reaches 200mV

and a current trip occurs.

Current Trip Voltage Setting

The

current

control

trip

value

is

set

by

connecting a resistor between ISET and GND.

When ISET is floating, the current trip voltage is

set to its default (200mV). If a resistor is

connected between ISET and GND, the current

trip voltage can be reduced below 200mV to

reduce power loss on the sense resistor. The IC

needs about 0.3ms to detect whether a resistor

is available on ISET when the IC starts up for

the first time. During this time, the IC is not

switching. The relationship of the current trip

voltage and RISET is calculated with Equation (1):

 

ITRIP

ISET

40

V

0.2

Rk

Ω



(1)

For example, if RISET is 80kΩ, the trip voltage is

100mV. For better accuracy, a

40kΩ to 80kΩ

resistance

is

recommended

to

achieve

a

200mV to 100mV current trip voltage.

Start-Up Sequence

The IC needs about 0.3ms to detect whether a

resistor is available on ISET when the IC starts

up for the first time. During this time, the IC is

not switching.

VCC LDO Regulator

The IC employs a low-dropout (LDO) regulator

to provide a constant voltage (5V) at VCC. The

VCC voltage (VVCC) is used for the internal

power supply of the logic circuit and driver

circuit. When the input voltage drops, VVCC

drops together with VIN. If VVCC drops below

4.8V, the IC triggers a power reset sequence

and shuts down. The IC resumes normal

operation when VVCC exceeds 5.1V.

High-Side MOSFET (HS-FET) Driver

The M1 and M3 high-side MOSFETs (HS-FETs)

are N-channel MOSFETs. When M1 and M3

turn on, a bootstrap supply voltage (VBSTx)

across BST1 and BST2 is required. VBSTx is

generated by a combination of the internal

charge pump and a 5V VCC. This allows the IC

to operate at 100% duty cycle to provide

enough driver voltage for the M1 and M3 HS-

FETs.

Over-Current Protection (OCP)

The over-current protection (OCP) circuit limits

the current through each MOSFET by reducing

the gate driver voltage to the MOSFET. If the

MOSFET current remains in the over-current

(OC) condition (above IOCP) for longer than the

OC deglitch time, all MOSFETs in the H-bridge

are disabled

and nFAULT is driven low.