Hi all,
I need to drive a small vibration motor. The datasheet is in Chinese but i have translated the specification:
1. Voltage: DC1.5V 3.0V
2. Current: 75mA max
3. RPM: 10000 +/- 2000 rpm
4. Start Voltage: DC0.5V 1.5V Max
I don't quite understand what the start voltage means. In any case, I like to drive this motor with a transistor circuit. I read this design note on using discrete components to drive a vibration motor:
https://www.precisionmicrodrives.co...discrete-driver-circuits-for-vibration-motors
Where they recommended using a MOSFET with the following setup:
**broken link removed**
I am using VDD directly from 3 x AAA batteries (4.5V) and the PWM signal is coming from a microcontroller at 3.3V. A few questions here.
1. n-Channel MOSFET is active high, so when PWM signal is at logic low, motor does not move. For p-Channel MOSFET, it is active LOW, so my PWM signal needs to be at logic HIGH to turn off the motor. Assuming I am using the p-Channel design, then my MCU PWM pin will need to be constantly high when the motor is to be turn off. Will this increase consumption on the MCU since I am setting the PWM pin constantly high? So it is better to use a n-Channel MOSFET instead?
2. Can I used a BJT NPN instead of a MOSFET? To save cost in the design.
3. Do I need a current limiting resistor between VDD and the motor? Since the motor is rated at 3V max and my supply is 4.5V. How do I calculate the value of this current limiting resistor?
Thanks in advance.
I need to drive a small vibration motor. The datasheet is in Chinese but i have translated the specification:
1. Voltage: DC1.5V 3.0V
2. Current: 75mA max
3. RPM: 10000 +/- 2000 rpm
4. Start Voltage: DC0.5V 1.5V Max
I don't quite understand what the start voltage means. In any case, I like to drive this motor with a transistor circuit. I read this design note on using discrete components to drive a vibration motor:
https://www.precisionmicrodrives.co...discrete-driver-circuits-for-vibration-motors
Where they recommended using a MOSFET with the following setup:
**broken link removed**
I am using VDD directly from 3 x AAA batteries (4.5V) and the PWM signal is coming from a microcontroller at 3.3V. A few questions here.
1. n-Channel MOSFET is active high, so when PWM signal is at logic low, motor does not move. For p-Channel MOSFET, it is active LOW, so my PWM signal needs to be at logic HIGH to turn off the motor. Assuming I am using the p-Channel design, then my MCU PWM pin will need to be constantly high when the motor is to be turn off. Will this increase consumption on the MCU since I am setting the PWM pin constantly high? So it is better to use a n-Channel MOSFET instead?
2. Can I used a BJT NPN instead of a MOSFET? To save cost in the design.
3. Do I need a current limiting resistor between VDD and the motor? Since the motor is rated at 3V max and my supply is 4.5V. How do I calculate the value of this current limiting resistor?
Thanks in advance.