AN1625 Datasheet, PDF (1/39 Pages) STMicroelectronics – L6235 THREE PHASE BRUSHLESS DC MOTOR DRIVER

AN1625
APPLICATION NOTE
L6235 THREE PHASE BRUSHLESS DC MOTOR DRIVER
by Vincenzo Marano
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.
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,
a centralized logic circuit to decode hall effect sensors and a constant t_OFF PWM current control technique (Syn-
chronous mode) plus other added features for safe operation and flexibility.
Figure 1. L6235 Block Diagram.
VBOOT
VCP
DIAG
EN
BRAKE
FWD/REV
H₃
H₂
H₁
V_BOOT
CHARGE
PUMP
THERMAL
PROTECTION
OCD
OCD1
OCD2
OCD3
OCD
HALL-EFFECT
SENSORS
DECODING
LOGIC
GATE
LOGIC
V_BOOT
OCD1
10V
V_BOOT
OCD2
10V
V_BOOT
VS_A
OUT1
OUT2
SENSE_A
VS_B
RCPULSE
TACHO
TACHO
MONOSTABLE
10V 5V
VOLTAGE
REGULATOR
OCD3
10V
OUT3
ONE SHOT
MONOSTABLE
PWM
MASKING
TIME
+
SENSE
-
COMPARATOR
SENSE_B
VREF
RCOFF
D99IN1095B
October 2003
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