TY - GEN
T1 - Capacitor-current-sensor calibration technique and application in a 4-phase buck converter with load-transient optimization
AU - Huang, Szu Yu
AU - Fang, Kuan Yu
AU - Huang, Yi Wei
AU - Chien, Shih Hsiung
AU - Kuo, Tai Haur
PY - 2016/2/23
Y1 - 2016/2/23
N2 - For switching DC-DC converters, a large and rapid load-current transient ΔIload causes a large output voltage undershoot ΔVUS and long settling time ts if the transient responses are slow [1]. Since the output capacitor current ICo instantly reflects ΔIload, transient response optimization for minimizing ΔVUS and ts with given charging and discharging slopes of inductor current ILo can be achieved by obtaining an accurate ICo and well-controlling the ILo charging time tch and discharging time tdch [1]. However, ICo sensing accuracy is degraded if the output capacitor's impedance ZCo, comprising the capacitance CO, equivalent series resistance RESR and inductance LESL, varies with different output voltage VO, process variation, and/or PCB parasitics, leading to non-minimized ΔVUS and ts. An off-chip capacitor-current-sensor (CCS) calibration technique is reported in [2]; however, LESL is not considered, so the high-frequency information of ΔIload is inaccurately sensed when large and rapid ΔIload occurs. On the other hand, to well-control the tch and tdch of ILo, the transient-optimized feedback circuit reported in [1] minimizes ΔVUS and ts. However, optimization can be achieved only under fixed CO, output inductor LO, input voltage VIN, and VO.
AB - For switching DC-DC converters, a large and rapid load-current transient ΔIload causes a large output voltage undershoot ΔVUS and long settling time ts if the transient responses are slow [1]. Since the output capacitor current ICo instantly reflects ΔIload, transient response optimization for minimizing ΔVUS and ts with given charging and discharging slopes of inductor current ILo can be achieved by obtaining an accurate ICo and well-controlling the ILo charging time tch and discharging time tdch [1]. However, ICo sensing accuracy is degraded if the output capacitor's impedance ZCo, comprising the capacitance CO, equivalent series resistance RESR and inductance LESL, varies with different output voltage VO, process variation, and/or PCB parasitics, leading to non-minimized ΔVUS and ts. An off-chip capacitor-current-sensor (CCS) calibration technique is reported in [2]; however, LESL is not considered, so the high-frequency information of ΔIload is inaccurately sensed when large and rapid ΔIload occurs. On the other hand, to well-control the tch and tdch of ILo, the transient-optimized feedback circuit reported in [1] minimizes ΔVUS and ts. However, optimization can be achieved only under fixed CO, output inductor LO, input voltage VIN, and VO.
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U2 - 10.1109/ISSCC.2016.7417990
DO - 10.1109/ISSCC.2016.7417990
M3 - Conference contribution
AN - SCOPUS:84962826211
T3 - Digest of Technical Papers - IEEE International Solid-State Circuits Conference
SP - 228
EP - 229
BT - 2016 IEEE International Solid-State Circuits Conference, ISSCC 2016
PB - Institute of Electrical and Electronics Engineers Inc.
T2 - 63rd IEEE International Solid-State Circuits Conference, ISSCC 2016
Y2 - 31 January 2016 through 4 February 2016
ER -