- The design can help designers in enabling soft-start operations and increasing the accuracy up to 95 per cent in DC motors.
- This low-cost solution has a reduced schematic which helps in easy integration with other circuits.
Designers working on solutions related to Home automation, digital appliances and Motor based Applications often use PWM(Pulse Width Modulation) signals to mimic the features of an analogue signal. As a digital signal work on High and Low characteristics which is a 2 stage output, PWM signal is based on providing an analogue signal through a digital source.
The reference design provides all the details required for the development of a PWM signal generator. The design can be implemented in intensity control or speed control devices for various DC applications.
How the PWM generation occurs?
This circuit utilizes a triangle wave generator and comparator to generate a pulse-width-modulated (PWM) waveform with a duty cycle that is inversely proportional to the input voltage. An op-amp and comparator generate a triangular waveform which is passed to the inverting input of a second comparator.
Bypassing the input voltage to the non-inverting comparator input, a PWM waveform is produced. Negative feedback of the PWM waveform is fed to an error amplifier to utilise and ensure high accuracy and linearity of the output.
The design characteristics of Circuit for an Accuracy of 95 per cent
The circuit requires an input supply voltage of -2 V to +2 V to provide an output PWM signal with a 5 Volt amplitude. The circuit generates a 500 kHz frequency signal which helps in easy interface with different microcontrollers. The design is equipped with ESD and Overvoltage Protection to provide longer durability and isolation from the incoming back currents.
The design has been released and developed by Texas Instruments and the design includes all the necessary documents for open-source prototyping of the circuit. All the technical documents can be downloaded here.