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AN1625

APPLICATION NOTE

October 2003

1

INTRODUCTION

For small-motor applications many appliance designers favor modern three phase brushless DC motors be-

cause of the high efficiency (as great as 95%) and small size for a given delivered power. Designers have to

handle control logic, torque and speed control, power-delivery issues and ensure safe operation in every load

condition. The L6235 is a highly integrated, mixed-signal power IC that allows to easily design a complete motor

control system for BLDC motor. Figure 1 shows the L6235 block diagram. The IC integrates six Power DMOS,

chronous mode) plus other added features for safe operation and flexibility.

Figure 1. L6235 Block Diagram.

CHARGE

PUMP

VOLTAGE

REGULATOR

HALL-EFFECT

SENSORS

DECODING

LOGIC

THERMAL

PROTECTION

TACHO

MONOSTABLE

OCD1

OCD

OCD

OCD2

10V

5V

VCP

GATE

LOGIC

VBOOT

OUT1

OUT2

OUT3

DIAG

EN

FWD/REV

BRAKE

RCPULSE

D99IN1095B

TACHO

RCOFF

OCD3

ONE SHOT

MONOSTABLE

MASKING

TIME

OCD1

10V

OCD2

10V

OCD3

10V

SENSE

COMPARATOR

+

-

PWM

VREF

by Vincenzo Marano

L6235 THREE PHASE BRUSHLESS DC MOTOR DRIVER

Modern motion control applications need more flexibility that can be addressed only with specialized

ICs products. The L6235 is a fully integrated motor driver IC specifically developed to drive a wide range

of BLDC motors with Hall effect sensors. This IC is a one-chip cost effective solution that includes

several unique circuit design features. These features, including a universal decoding logic that allows

the device to be used with most common Hall effect spacing, will be described. The principal aim of this

development project was to produce an easy to use, fully protected power IC. In addition several key

functions as protection circuit and high speed PWM current control allow to drastically reduce the

external components count to meet requirements for many different applications.