Pulse-Width Modulation (Pwm) Circuit - Epson L-1000 Technical Manual

REV.-A
PRINCIPLES OF OPERATION

2.2.1.7 Pulse-Width Modulation (PWM) Circuit

Figure 2-19 shows the internal circuit of the NJM2355 IC. The PWM comparator operates as follows:
In circuit 1 the output from AMP 1 flows into the negative terminal of comparator 1, and the outputs from AMP
2 and AMP 3 in circuit 2 flow into the negative terminal of PWM comparator 2 without wired OR. Dead-time
control voltage is also input to additional negative terminals of both PWM comparators 1 and 2.
A sawtooth waveform from the oscillator is input to the positive terminals. The sawtooth waveform from the
oscillator causes the comparators to generate pulses as shown in Figure 2-20.
Figure 2-19. NJM2355 Internal Circuit
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LQ-500/ L-1000