Analog Pulse Width Modulator. Takes analog input signal like audio or ultrasound or DC voltage and modulates into differential output signal PWM1/PWM2 suitable for H-Bridge control.
Applications:
- Class D Audio Power Amplifier
- DC/DC power converter
- LED Driver
- 3.5mm Phono Jack J1. This is suitable for connecting Audio signal source using Stereo Cable and 3.5mm male connector.
- 2.54mm Header J2. Can be used to connect with another board as signal source like I2S DAC or Bluetooth Transceiver Module.
- Potentiometer RV2. In this case variable input is set via resistive potentiometer suitable for DC/DC converter applications.
- No Feedback. R9 resistor should be populated and R15 unpopulated making feedback differential amplifier disconnected. Output pulse width is proportianal to input signal with default full scale input level of 1Vrms.
- With Feedback. Regulation is possible by closing negative Feedback circuit (see Class-D amplifier application) by populating R15 resistor and leaving R9 unpopulated. Feedback input connects to final regulation output (H-Bridge power stage output) through resistor divider network in order to adjust full scale of output (0-VCC) to full scale of input (1Vrms).
All parts listed in LanmiLab_PWM_Modulator_BOM.csv. Or use Application specific BOM from PWM_Modulator/Applications/.
Send LanmiLab_PWM_Modulator_gerbers.zip fabrication files to PCB Manufacturer.
Download and use ibom.html as soldering guide.
Use Trimpot RV1 to set desired PWM frequency. If oscilloscope is available use it to measure CLOCKOUT signal at P2 pin 10, otherwise use multimeter to measure RV1 resistance (between pins 1-2) and calculate frequency according:
F=R7/(R6*(RV1+R5)*C)/4.