1. Skip to navigation
  2. Skip to content
  3. Skip to sidebar

LT1715 Rail-to-Rail 1MHz Pulse Width Modulator

Rail-to-Rail 1MHz Pulse Width Modulator

In applications where a high frequency variable PWM generator is needed, the LT1715 provides a small and simple solution, as shown in the circuit of Figure 10. The top comparator, U1A, acts as a ramp generator. Biasing resistors R1 and R2 and a 7:1 positive feedback ratio through R3 set the positive input to approximately 2.5V±250mV. The inverting RC feedback creates a relaxation oscillator by tripping the comparator into the opposing output state each time it passes through the ±250mV positive input voltage. The 880kHz triangle wave created on C1 is then passed to the inverting input of the second comparator, U1B. The input signal to be modulated, referenced from 0V to 5V,is first divided to match the 2.5V ±250mV ramp input, and then the duty cycle is set with the second comparator acting as a threshold detector.

 


Software

LTspice

LTspice® software is a powerful, fast and free simulation tool, schematic capture and waveform viewer with enhancements and models for improving the simulation of switching regulators. Click here to download LTspice

To launch a ready to run LTspice demonstration circuit for this part:

  • Step 1: If you have not installed LTspice on this computer, download and install LTspice
  • Step 2: Once LTspice is installed, click on the link(s) below to launch the simulation
  • Step 3: If LTspice does not automatically open after clicking the link above, you can instead run the simulation by right clicking on the link and selecting "Save Target As." After saving the file to your computer, start LTspice and open the demonstration circuit by selecting 'Open' from the 'File' menu

To explore other ready to run LTspice demonstration circuits, please visit our Demo Circuits Collection.

View More Pulse Width Modulators Solutions

View All - List View