DC Motor 8 click
Weight: 25 g
PID: MIKROE-2893
DC Motor 8 click is a DC motor driver. It can drive simple DC motors with brushes, providing
them with a significant amount of current and voltage up to 40V. The click has one control input,
that uses the PWM signal from the host MCU. It uses the half-bridge topology to regulate the
speed of the motor rotation, employs advanced dead-time circuitry that monitors the output
stage, providing maximum switching efficiency and features an advanced technique to avoid
shoot-through currents.
Features, such as high-efficiency factor, low overall power consumptions and complete isolation
of the output stage, enable this device to be used in various battery operated handheld tools, fans
and in general - whenever a powerful and reliable DC motor driver is required.
How does it work?
DC Motor 8 click relies on the MIC4605, 85V half-bridge MOSFET driver with adaptive dead
time and shoot-through protection, from Microchip. This IC uses the input on its PWM pin to
regulate the switching state of the output MOSFETs. The fact that it is 85V tolerant, allows for a
substantial margin against kickback voltage that appears as the result of the rotation of the motor.
In practice, at least twice the power supply used for the motor should be considered as a safe
margin. This IC has more than enough to accommodate for the maximum voltage allowed on its
input, which is 40V.
DC Motor 8 works in a half-bridge topology, which means that it can run the connected motor in
one direction only. However, the polarity of the connected motor can be flipped, which will
result in a change of the rotational direction of the motor. The connected input voltage must not
be reversed, it has to stay connected as labeled on the PCB. Although the maximum input
voltage rating is 40V, it is a good practice never to supply the motor with the maximum allowed
voltage, as it may result in overheating of the MOSFETs and other components, depending on
the used motor and the mechanical load it is exposed to. The device should never be pushed to
work at maximum allowed ratings.
While the PWM input is at the HIGH logic state, HO output pin that drives the high side power
MOSFET is active and the circuit is closed through the high side power MOSFET, motor coil,
and the ground. When the PWM input signal goes LOW, it forces the HO output to also go low,
within about 35ns. The HS pin monitors the driver state - when the HS voltage drops under 2.2V,
the high side MOSFET is closed and after a short delay (about 35ns of rise time) LO output is
activated. A further drop of the HS voltage causes a latch, which can be only reset by the PWM
signal HIGH logic level. If the HS level fails to drop under 2.2V, the internal 250ns delay is
activated and the HS pin is latched anyway, after that. This prevents the HS ringing to cause an
undetermined state of the LO output. When the PWM signal goes HIGH again, it will force the
LO output to a LOW within another 35ns, after which the HO pin can start going into the HIGH
level again.
This mechanism ensures that no shoot-through ever occurs. Shoot-through happens when both
MOSFETs are active and when the current goes right through them, from the power supply to
the ground, causing dissipation, ringing and even damage in some cases.
Besides the PWM pin routed to the mikroBUS™, the EN pin used to enable the device is also
routed to the mikroBUS™ CS pin. Logic HIGH will set the device to work in normal mode,
while LOW logic level will put the device into the power conservative shutdown mode. This pin
is pulled HIGH with the onboard resistor.
The VIN power terminal used to provide up to 40V of power supply for the DC motor, is
completely isolated from the driver circuitry. However, to operate correctly - the driver has to
provide enough voltage for activating the MOSFETs. For this purpose, DC Motor 8 click
employs a buck converter made of MIC2606, a 2MHz boost regulator from Microchip. The boos
regulator circuitry provides 12V out of 5V from the mikroBUS™, which allows for ideal
MOSFET switching conditions, keeping the resistance through the MOSFET (RDSON) at
optimal levels.
VOUT terminal is used to connect a load. A small to medium powered DC motor with two
connection points and up to 40V can be used with this click board™. The voltage at the VIN
terminal is used to power the motor on, while the click itself is being powered from the
mikroBUS™ voltage rails. For a proper operation, both 3.3V and 5V voltages must be present on
the mikroBUS™.
Specifications
Type
Applications
On-board
modules
DC
It can be used in various battery operated handheld tools, fans and in general -
whenever a powerful and reliable DC motor driver is required.
MIC4605, 85V half-bridge MOSFET driver with adaptive dead time and shoot-through
protection and MIC2606, a 2MHz boost regulator, both from Microchip
DC Motor 8 features a good switching efficiency, low overall power consumptions and
complete isolation of the output stage. It employs advanced adaptive dead-time and
intelligent shoot-through protection mechanisms.
GPIO,PWM
Key Features
Interface
Input Voltage 3.3V or 5V
Click board
size
M (42.9 x 25.4 mm)
Pinout diagram
This table shows how the pinout on DC Motor 8 click corresponds to the pinout on the
mikroBUS™ socket (the latter shown in the two middle columns).
Notes
Pin
NC
NC
EN
NC
NC
NC
Power supply
Ground
1
2
3
4
5
6
AN
RST
CS
SCK
MISO
MOSI
3.3V
GND
PWM
INT
RX
TX
SCL
SDA
5V
GND
16
15
14
13
12
11
10
9
Pin
PWM
NC
NC
NC
NC
NC
+5V
GND
Power supply
Ground
Notes
+3.3V 7
GND
8
DC Motor 8 click electrical specifications
Description
Input voltage
Output Current
Min Typ Max Unit
0
1
40
V
A
Onboard settings and indicators
Label Name Default
PWR PWR
TB1
VIN
-
-
-
Description
Power LED Indicator
VIN Terminal
VOUT Terminal
TB2 VOUT
Software support
We provide a library for DC Motor 8 click on our LibStock page, as well as a demo application
(example), developed using MikroElektronika compilers. The demo application can run on all
the main MikroElektronika development boards.
Library Description
Initializes and defines GPIO driver and constant values wich can be used in example code and
also enables chip.
Key functions
void dcmotor8_setFreq(uint16_t freq, uint8_t step)
- Function sets frequency and
current duty for PWM Timer5.
void dcmotor8_startMotor(uint16_t delayTime, uint8_t stopEnable)
- Function sets
delay time witch decides when PWM Timer5 will be stoped and started again. If stopEnable is 1
the PWM Timer5 will be stoped, and if 0 will be not stoped.
Examples Description
The demo application is composed of three sections:
•
•
•
System Initialization - Initializes peripherals and pins.
Application Initialization - Initializes click driver.
Application Task - Sets frequency and current duty of PWM Timer5 and decides will Timer5 be
stoped and when. Also makes decide when Timer5 will be started again.
void
applicationTask()
{
char
txt[4]
=
{0};
//Sets frequency of 20kHz and current duty of 36000 (Duty range is from 0 to
65535)
dcmotor8_setFreq(_DCMOTOR8_20KHZ, _DCMOTOR8_DUTY_36000);
//Enables motor stop working and sets 20 seconds working time and 4 seconds
disabling time
dcmotor8_startMotor(_DCMOTOR8_DELAY_20SEC, _DCMOTOR8_DELAY_4SEC,
_DCMOTOR8_STOP_ENABLE);
//Writes on USB UART value of current duty for PWM Timer5
IntToStr(pwmPeriod, txt);
mikrobus_logWrite("Value of PWM timer period is: ", _LOG_TEXT);
mikrobus_logWrite(txt, _LOG_LINE);
Delay_ms(100);
}
stm32/stm8
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