MLX90401
Brushless DC Motor Controller
3 Glossary of terms
FET
Field Effect Transistor
Pulse Width Modulation
PWM
Undervoltage
Overcurrent
State in which the power supply voltage is lower than the operation range of the
device.
State in which the current flowing in a certain device (e.g. output driver, motor, etc.)
exceeds a maximum defined level. This includes both overload and short-circuit
currents.
4 Pin definitions and description
Pin
Symbol
Description
1
Supply voltage
VREF Out
External power supply voltage.
2
Regulated reference voltage (12V) derived from V+.
Used to power external components and Hall-effect
sensors, and for boost voltage.
3-5
6
Hall "A", "B" and "C" Inputs
Fwd/Rev Input
Hall IC open collect inputs.
Pull-up resistance of 3.3k to 5V.
The Forward/Reverse Input is used to change the
direction of motor rotation. A logic high state selects
forward direction; a logic low state selects reverse
direction.
Pull-up resistance of 3.3k to 5V.
7
Speed Adjust Input/Disable
Potentiometer input - adjusts the PWM duty cycle setting
current, allowing a manual speed adjustment.
Disable input can be used in combination with any type
of switch (thermal, Hall, etc.). A logic low on this pin
selects the disable function.
8
9
Oscillator R/C
/Brake Input
The Oscillator frequency is set with the values selected
for the timing components RRC and CRC.
A logic high state at this input allows the motor to run,
while a low state causes rapid deceleration.
Pull-up resistance of 3.3k to 5V.
10
11
Analog ground
Ground pin for analog blocks.
60°/120° Select Input
A logic high state on this pin selects 60° sensor electrical
phasing, a logic low state selects 120°.
Pull-up resistance of 3.3k to 5V.
12
Power Ground
Ground pin for digital and output drivers.
Three push-pull drivers for direct drive of bottom power
switch transistors.
13-15
Gate Bottom "A", "B" and
"C"
16, 19, 22
Feedback "A", "B" and "C"
Negative supply of the top drive circuitry. It is the
connection for the negative side of the bootstrap
capacitor, the top power FET Source, the bottom power
FET Drain, and the Phase C output.
17, 20, 23
18, 22, 24
Gate Top "A", "B" and "C"
Cap Boost "A", "B" and "C"
Three push-pull drivers for direct drive of top power
switch transistors.
Positive supply of the top drive circuitry. The boost
capacitor is connected between this pin and Feedback.
Table 1: Pin definitions and description
3901090401
Rev 005
Page 3 of 13
Data sheet
Oct/05
MELEXIS [ Melexis Microelectronic Systems ]
