Abstract
This paper presents a voltage mode pulse width modulator (PWM) using single operational transresistance amplifier (OTRA). The proposed PWM consists of a relaxation oscillator output which is modulated using modulating signal. PSPICE simulation results and experimental results have been included to verify the theoretical analysis.
Highlights
Pulse width modulation (PWM) scheme is widely used in communication systems, DC motor speed controller, power conversion control circuits [1,2,3], and instrumentation
In PWM, the width of pulses of a pulse train is changed in accordance to voltage level of modulating signal. e PWM generators are available in Integrated Circuits (ICs) form; the internal circuitry is somewhat complex and typically consists of current sources, ip- op, comparators, and analog switches [4]
Extensive literature review reveals that PWMs based on this concept are available using different active analog building blocks such as op-amps [6], current conveyor II (CCII) [4], and operational transconductance ampli er (OTA) [7, 8]
Summary
Pulse width modulation (PWM) scheme is widely used in communication systems, DC motor speed controller, power conversion control circuits [1,2,3], and instrumentation. E open literature suggests that a PWM pulse train can be produced with the use of voltage-controlled delay lines [9], current-controlled delay cells [10], and voltage-controlled phase shi er [11] wherein the underlying concept is not the same as used in [4,5,6,7,8]; that is, the comparison of modulating signal with reference triangular/sawtooth waveform [9] uses two voltage-controlled delay lines, a xed delay element, two rising edge detectors, along with an RS latch to generate a 0%–50% duty cycle at the output of the latch.
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