ML4435 Motor Controller Datasheet

ML4435 Datasheet, PDF, Equivalent


Part Number

ML4435

Description

Sensorless BLDC Motor Controller

Manufacture

Micro Linear

Total Page 14 Pages
Datasheet
Download ML4435 Datasheet


ML4435
PRELIMINARY
ML4435 Sensorless BLDC Motor Controller
GENERAL DESCRIPTION
The ML4435 provides all the circuitry for sensorless
speed control of 3 phase Brushless DC Motors. Controller
functions include start-up circuitry, Back EMF commuta-
tion control, Pulse Width Modulation (PWM) speed con-
trol, pulse-by-pulse current limiting, motor coasting, and
under-voltage protection.
Motor starting is accomplished by commutating the motor
at a low frequency to produce low speed motion. The
low speed motion is used to generate a Back EMF signal.
A back EMF sampling circuit locks on to the motors posi-
tion and controls commutation timing by forming a phase
locked loop (PLL). The commutation control circuitry also
outputs a speed feedback signal used in the speed control
loop. The speed control loop consists of an error amplifier
and PWM comparator that produces a PWM duty cycle
for speed regulation. Motor current is limited by a pulse-
by-pulse PWM shutdown comparator that is tripped by
the voltage across an external current sense resistor. Com-
mutation control, PWM speed control, and current limit-
ing are combined to produce the output driver signals.
Six output drivers are used to provide gating signals to an
external 3 phase bridge power stage sized for the Brush-
less DC (BLDC) motor voltage and current requirements.
Additional functions include a motor coast function and
an under voltage lock out circuit to shut down the output
drivers in the event of a low voltage condition on the VCC
to the ML4435.
FEATURES
n Proprietary back-EMF sensing commutation technique
for motor communication without hall effect sensors
n PWM pulse-by-pulse current limiting to protect motor
and FET drivers
n Stand-alone operation; motor starts and stops with
power applied to the IC*
n Soft-start function limits start-up current
n PWM speed control for efficiency and minimum FET
sizing
n Onboard under voltage lock out and power fail detect
n Tach output senses commutation of the motor
PRELIMINARY DATASHEET
* Some External Components Required.
May, 2000

ML4435
PRELIMINARY
ML4435
WARRANTY
Micro Linear makes no representations or warranties with respect to the accuracy, utility, or completeness of the contents of
this publication and reserves the right to make changes to specifications and product descriptions at any time without notice.
No license, express or implied, by estoppel or otherwise, to any patents or other intellectual property rights is granted by this
document. The circuits contained in this document are offered as possible applications only. Particular uses or applications
may invalidate some of the specifications and/or product descriptions contained herein. The customer is urged to perform
its own engineering review before deciding on a particular application. Micro Linear assumes no liability whatsoever,
and disclaims any express or implied warranty, relating to sale and/or use of Micro Linear products including liability
or warranties relating to merchantability, fitness for a particular purpose, or infringement of any intellectual property
right. Micro Linear products are not designed for use in medical, life saving, or life sustaining applications.
© Micro Linear 2000.
is a registered trademark of Micro Linear Corporation. All other trademarks are
the property of their respective owners.
Products described herein may be covered by one or more of the following U.S. patents: 4,897,611; 4,964,026; 5,027,116;
5,281,862; 5,283,483; 5,418,502; 5,508,570; 5,510,727; 5,523,940; 5,546,017; 5,559,470; 5,565,761; 5,592,128; 5,594,376;
5,652,479; 5,661,427; 5,663,874; 5,672,959; 5,689,167; 5,714,897; 5,717,798; 5,742,151; 5,747,977; 5,754,012;
5,757,174; 5,767,653; 5,777,514; 5,793,168; 5,798,635; 5,804,950; 5,808,455; 5,811,999; 5,818,207; 5,818,669; 5,825,165;
5,825,223; 5,838,723; 5.844,378; 5,844,941. Japan: 2,598,946; 2,619,299; 2,704,176; 2,821,714. Other patents are pending.
2 PRELIMINARY DATASHEET May, 2000


Features PRELIMINARY ML4435 Sensorless BLDC Motor Controller GENERAL DESCRIPTION The ML4 435 provides all the circuitry for sens orless speed control of 3 phase Brushle ss DC Motors. Controller functions incl ude start-up circuitry, Back EMF commut ation control, Pulse Width Modulation ( PWM) speed control, pulse-by-pulse curr ent limiting, motor coasting, and under -voltage protection. Motor starting is accomplished by commutating the motor a t a low frequency to produce low speed motion. The low speed motion is used to generate a Back EMF signal. A back EMF sampling circuit locks on to the motor s position and controls commutation tim ing by forming a phase locked loop (PLL ). The commutation control circuitry al so outputs a speed feedback signal used in the speed control loop. The speed c ontrol loop consists of an error ampli er and PWM comparator that produces a PWM duty cycle for speed regulation. M otor current is limited by a pulseby-pu lse PWM shutdown comparator that is tripped by the voltage across.
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