TY - JOUR AU1 - Kim, Hyung-won AU2 - Jeong, Hyeim AU3 - Yu, Junho AU4 - Lee, Chan-Soo AU5 - Kim, Nam-Soo AB - PurposeThis paper aims to propose a low-power complementary MOS (CMOS) current sensor for control circuit in an integrated DC-DC buck converter.Design/methodology/approachThe integrated DC-DC converter, which is composed of feedback control circuit and power block, is designed with 0.35-µm CMOS process. Current sensor in the control circuit is integrated with sense-FET and voltage-follower circuits to reduce power consumption and improve its sensing accuracy. In the current-sensing circuit, the size ratio of the power metal oxide semiconductor field effect transistor (MOSFET) to the sensing transistor (K) is 1,000, and a current-mirror is used for a voltage follower. N-channel MOS acts as a switching device in the current-sensing circuit, where the sensing FET is in parallel with the power MOSFET. The amplifier and comparator are designed to obtain a high gain and a fast transient time.FindingsExperiment shows that the current sensor is operated with accuracy of more than 85 per cent, and the transient time of the error amplifier is controlled within 100 µs. The sensing current is in the range of a few hundred µA at a frequency of 0.6-2 MHz and an input voltage of 3-5 V. The output voltage is obtained as expected with the ripple ratio within 5 per cent.Originality/valueThe proposed current sensor in DC-DC converter provides an accurately sensed inductor current with a significant reduction in power consumption in the range of 0.2 mW. High-accuracy regulation is obtained using the proposed current sensor. As the sensor utilizes simple switch-type voltage follower and sense-FET, it can be widely applied to other low-power applications such as high-frequency oscillator and over-current protection circuit. TI - Low-power CMOS integrated current sensor for current-mode DC-DC buck converter JF - Microelectronics International DO - 10.1108/MI-07-2017-0035 DA - 2018-04-03 UR - https://www.deepdyve.com/lp/emerald-publishing/low-power-cmos-integrated-current-sensor-for-current-mode-dc-dc-buck-aWVE0bzSLX SP - 115 EP - 123 VL - 35 IS - 2 DP - DeepDyve ER -