Transfer function of current modulator in PWM converters with current-mode control

Several different expressions have been derived in previous publications for the transfer function of the current modulator used in pulsewidth modulated (PWM) dc-dc power converters with current-mode control. These expressions give results higher than the measured ones and exhibit many other problems, e.g., one expression gives an infinite value when no slope compensation is used. This paper presents a derivation for the transfer function of the current modulator used in PWM converters with fixed-frequency, trailing-edge modulation, peak-current-mode control for two cases: without and with slope compensation. In addition, feedforward terms are also derived.