MC33035
PIN FUNCTION DESCRIPTION
Pin
1, 2, 24
3
4, 5, 6
7
8
9
B
T
, A
T
, C
T
Fwd/Rev
S
A
, S
B
, S
C
Output Enable
Reference Output
Current Sense Noninverting Input
Symbol
Description
These three open collector Top Drive outputs are designed to drive the external
upper power switch transistors.
The Forward/Reverse Input is used to change the direction of motor rotation.
These three Sensor Inputs control the commutation sequence.
A logic high at this input causes the motor to run, while a low causes it to coast.
This output provides charging current for the oscillator timing capacitor C
T
and a
reference for the error amplifier. It may also serve to furnish sensor power.
A 100 mV signal, with respect to Pin 15, at this input terminates output switch
conduction during a given oscillator cycle. This pin normally connects to the top
side of the current sense resistor.
The Oscillator frequency is programmed by the values selected for the timing
components, R
T
and C
T
.
This input is normally connected to the speed set potentiometer.
This input is normally connected to the Error Amp Output in open loop applications.
This pin is available for compensation in closed loop applications.
This open collector output is active low during one or more of the following
conditions: Invalid Sensor Input code, Enable Input at logic 0, Current Sense Input
greater than 100 mV (Pin 9 with respect to Pin 15), Undervoltage Lockout
activation, and Thermal Shutdown.
Reference pin for internal 100 mV threshold. This pin is normally connected to the
bottom side of the current sense resistor.
This pin supplies a ground for the control circuit and should be referenced back to
the power source ground.
This pin is the positive supply of the control IC. The controller is functional over a
minimum V
CC
range of 10 to 30 V.
The high state (V
OH
) of the Bottom Drive Outputs is set by the voltage applied to
this pin. The controller is operational over a minimum V
C
range of 10 to 30 V.
These three totem pole Bottom Drive Outputs are designed for direct drive of the
external bottom power switch transistors.
The electrical state of this pin configures the control circuit operation for either 60°
(high state) or 120° (low state) sensor electrical phasing inputs.
A logic low state at this input allows the motor to run, while a high state does not
allow motor operation and if operating causes rapid deceleration.
10
11
12
13
14
Oscillator
Error Amp Noninverting Input
Error Amp Inverting Input
Error Amp Out/PWM Input
Fault Output
15
16
17
18
19, 20, 21
22
23
Current Sense Inverting Input
Gnd
V
CC
V
C
C
B
, B
B
, A
B
60°/120° Select
Brake
INTRODUCTION
The MC33035 is one of a series of high performance
monolithic DC brushless motor controllers produced by
Motorola. It contains all of the functions required to
implement a full–featured, open loop, three or four phase
motor control system. In addition, the controller can be made
to operate DC brush motors. Constructed with Bipolar Analog
technology, it offers a high degree of performance and
ruggedness in hostile industrial environments. The MC33035
contains a rotor position decoder for proper commutation
sequencing, a temperature compensated reference capable
of supplying a sensor power, a frequency programmable
sawtooth oscillator, a fully accessible error amplifier, a pulse
width modulator comparator, three open collector top drive
outputs, and three high current totem pole bottom driver
outputs ideally suited for driving power MOSFETs.
Included in the MC33035 are protective features
consisting of undervoltage lockout, cycle–by–cycle current
limiting with a selectable time delayed latched shutdown
mode, internal thermal shutdown, and a unique fault output
that can easily be interfaced to a microprocessor controller.
Typical motor control functions include open loop speed
control, forward or reverse rotation, run enable, and dynamic
braking. In addition, the MC33035 has a 60°/120° select pin
which configures the rotor position decoder for either 60° or
120° sensor electrical phasing inputs.
FUNCTIONAL DESCRIPTION
A representative internal block diagram is shown in
Figure 19 with various applications shown in Figures 36, 38,
39, 43, 45, and 46. A discussion of the features and function
of each of the internal blocks given below is referenced to
Figures 19 and 36.
Rotor Position Decoder
An internal rotor position decoder monitors the three
sensor inputs (Pins 4, 5, 6) to provide the proper sequencing
of the top and bottom drive outputs. The sensor inputs are
designed to interface directly with open collector type Hall
Effect switches or opto slotted couplers. Internal pull–up
resistors are included to minimize the required number of
external components. The inputs are TTL compatible, with
their thresholds typically at 2.2 V. The MC33035 series is
designed to control three phase motors and operate with four
of the most common conventions of sensor phasing. A
60°/120° Select (Pin 22) is conveniently provided and affords
the MC33035 to configure itself to control motors having
either 60°, 120°, 240° or 300° electrical sensor phasing. With
three sensor inputs there are eight possible input code
combinations, six of which are valid rotor positions. The
remaining two codes are invalid and are usually caused by an
open or shorted sensor line. With six valid input codes, the
8
MOTOROLA ANALOG IC DEVICE DATA
MOTOROLA [ MOTOROLA, INC ]
