Abstract: A design of an adaptive pseudo-fixed-frequency PWM modulator tailored for constant dead-time synchronous buck power management ICs is presentd. Operating in CCM mode, the modulator generates control signals through an SR flip-flop, demonstrating excellent transient response and steady-state performance. It provides a stable switching frequency that remains unaffected by input voltage, output voltage, or load current variations. The circuit design and layout were implemented using 0.18 µm BCD process, The results show that, under input conditions of 2.7 - 5.5 V, the pseudo-fixed-frequency PWM modulator reliably outputs a 1 MHz switching frequency.