ml4425 Microsemi Corporation, ml4425 Datasheet - Page 3

• Manufacturer Part Number: ml4425
• Description: Sensorless Bldc Motor Controller
• Manufacturer: Microsemi Corporation

PIN DESCRIPTION
PIN
1(30)
2(31)
3(32)
4(1)
5(3)
6(4)
7(5)
8(6)
9(7)
10(8)
11(9)
12(10) I
13(11) VCO/TACH
14(12) V
15(15) C
16(16) R
NAME
I
HA
HB
HC
SPEED COMP Speed control loop compensation is
C
V
SPEED SET
LA
LB
LC
LIMIT
SENSE
VCO
T
REF
VCO
DD
FUNCTION
This TTL level output corresponds
Motor current sense input. When
I
output drivers LA, LB, and LC are
shut off for a fixed time
determined by C
Active low output driver for the
phase A high-side switch
Active low output driver for the
phase B high-side switch
Active low output driver for the
phase C high-side switch
set by a series resistor and capacitor
from SPEED COMP to GND
A capacitor from C
the PWM oscillator frequency
6.9V reference voltage output
Speed loop input which ranges
from 0 (stopped) to V
(maximum speed)
Active high output driver for the
phase A low-side switch
Active high output driver for the
phase B low-side switch
Active high output driver for the
phase C low-side switch
Voltage on this pin sets the I
threshold voltage at 0.2
leaving this pin unconnected
selects an internally set threshold
to the signal used to clock the
commutation state machine. The
output frequency is proportional to
the motor speed when the back-
EMF sensing loop is locked onto
the rotor position
12V power supply input
A capacitor to GND sets the
voltage-to-frequency ratio of the
VCO
An resistor to GND sets up a
current proportional to the input
voltage of the VCO
SENSE
(Pin number in parenthesis is for TQFP package)
exceeds 0.2
IOS
T
to GND sets
REF
I
LIMIT,
I
LIMIT
the
SENSE
,
PIN
17(17) C
18(18) UV FAULT
19(19) C
20(20) SPEED FB
21(21) C
22(22) FB A
23(23) FB B
24(24) FB C
25(25) BRAKE
26(26) C
27(27) R
28(28) GND
NAME
AT
REF
RT
RR
IOS
FUNCTION
A capacitor to GND sets the time
that the controller stays in the
align mode
This output goes low when V
drops below the UVLO threshold,
and indicates that all output
drivers have been disabled
A capacitor to GND sets the time
that the controller stays in the
ramp mode
Output of the back-EMF sampling
circuit and input to the VCO. An
RC network connected to SPEED
FB sets the compensation for the
PLL loop formed by the back-EMF
sampling circuit, the VCO, and
the commutation state machine
A capacitor to between C
SPEED FB sets the ramp rate
(acceleration) of the motor when
the controller is in ramp mode
The motor feedback voltage from
phase A is monitored through a
resistor divider for back-EMF
sensing at this pin
The motor feedback voltage from
phase B is monitored through a
resistor divider for back-EMF
sensing at this pin
The motor feedback voltage from
phase C is monitored through a
resistor divider for back-EMF
sensing at this pin
A logic low input activates motor
braking by shutting off the high-
side output drivers and turning on
the low-side output drivers
A capacitor to GND sets the time
that the low-side output drivers
remain off after I
threshold
An 137k resistor to GND sets a
current proportional to V
used to set all the internal bias
currents except for the VCO
Signal and power ground
SENSE
ML4425
exceeds its
REF
RR
that is
and
DD
3