Buck converter IC for brushless DC motor drive using voltage‐mode PWM controller

Abstract

This study proposes a buck converter IC with voltage-mode pulse-width modulation (PWM) controller to provide a stable bias voltage for the brushless DC motor drive. The proposed buck converter IC comprises an error amplifier, a hysteresis comparator, a linear ramp generator, a driving circuit, a non-overlapping circuit, a bootstrap circuit and a level shifter. By integrating these proposed circuits into a single chip, the performance of buck converter chip could be improved significantly. The PWM controlled signal was used to generate a suitable output voltage by modifying the duty cycle. The advantage of this method is that the control method of the feedback circuit can be implemented easily, has a short ON time, and has effective noise immunity. After verifying the designed functions, the proposed IC was fabricated using TSMC 0.25 μm 1P3M complementary metal oxide semi-mixed signal process. Measurement results illustrate that the output voltage, output current, line regulation, load regulation, output ripple voltage and peak power efficiency were 5 V, 200 mA, 13.33 mV/V, 18.5 mV/A, 30 mV, and 68%, respectively, at an input voltage of 15 V and a switching frequency of 100 kHz. The chip area was ∼1.480 × 0.999 mm 2 .