About PWM signal specification

What is PWM?

Click here to learn What is PWM

How to Turn ON Laser Module at Full Power?

Connect 12V and GND of your laser module, then connect TTL/PWM higher then 2.5V (should lower then 15V), the laser will on at full power.

How to Turn ON Laser Module at 50% Power?

By input pwm signal at 50% duty cycle

What is PWM Signal Specifications?

  1. PWM frequency: 0 ~ 20KHz
  2. PWM Vpp: 2.5V ~12V (0~2V turn off, 2.5V~12V turn on, 2~2.5V unknow)
  3. Drive current capability should > 1mA

For conditions 1 and conditions 2, in most cases, there is no problem.

But how do I know is the current drive capability OK?

  1. Test your laser module and mske sure your laser module is working properly.
  2. Turn on PWM output at 100% at your control software.
  3. Without laser module connect, measure the voltage of your control board PWM output voltage by multimeter(DC gear), record as V1.
  4. Connect laser module to your control board, measure the voltage of your control board PWM output by multimeter(DC gear), record as V2.

If V1 is higher then 3.3V and V2 is lower 2.5V, that means your control board drive current capability is too low, you may need change another control board and try again.

How to measure PWM signal voltage?

Set your multimeter to the DC voltage gear. Connected the black probe to GND and the connect red probe to TTL / PWM. The display of the multimeter is your TTL / PWM voltage.

Does PWM frequency affect power output?

No, Only the PWM duty cycle determines the output power(make sure frequency is < 20KHz).