Motivation
This is the LFO module for my Next Generation Formant project. It provides triangle, ramp up, ramp down and square wave output (-5V to +5V). This design follows closely the original from the Elektor Formant. The power consumption is significantly reduced due to using low current LED and TL064.
Most noticeable change is moving to a "flat" design. The depth of the module is significantly reduced and most important no more potentiometer wiring is needed!
Specs and features
- Triangle, ramp up, ramp down and square wave output
- Output -5V to +5V
- Runs on +/-15V and +/-12V
- Power consumption below 10mA each rail
- Schematic NGF LFO
- Pictures
- Download docs
Implementation
Schematic
NGF LFO schematic back PCB
NGF LFO schematic front PCB
Description:
The oscillator consists of an integrator IC1A and an OpAmp Schmitt-Trigger IC1B. The triangle wave of the oscillator arises through the feedback of the trigger output to the input of the integrator. At the integrator output IC1A arises a triangle with the amplitude of the hysteresis of the Schmitt-Trigger. The input voltage of the integrator sets the rise and fall time of the voltage output. The square wave output is buffered with IC1C. The circuitry around IC1D provides the saw output. IC3C inverts the saw.
NGF LFO screenshot waveform
Special parts
None
