An integrated current sensing circuit with comparator function for a buck DC-DC converter in HV-CMOS

An integrated current sensing circuit with incorporated comparator function is presented. The current scaling is done in two independent steps, therefore very high current division ratio is obtained, which makes this circuit suitable for converters with large output currents. The additional comparator part eliminates the need for a separate comparator circuit, therefore reduces the design effort and complexity. The current sensing accuracy is in the range from 91.1% up to 99.6% for a wide range of output currents. Also, a high precision of the sensed current and a stable duty ratio of the converter for a wide range of temperatures and in process corner simulations are achieved. The complete buck converter is designed in 0.18 μm 50 V high-voltage (HV) CMOS technology.

[1]  R.C. Chang,et al.  A novel current sensing circuit for a current-mode control CMOS DC-DC buck converter , 2005, 2005 IEEE VLSI-TSA International Symposium on VLSI Design, Automation and Test, 2005. (VLSI-TSA-DAT)..

[2]  Philip K. T. Mok,et al.  On-chip current sensing technique for CMOS monolithic switch-mode power converters , 2002, 2002 IEEE International Symposium on Circuits and Systems. Proceedings (Cat. No.02CH37353).

[3]  S. Deuty.  Optimizing transistor performance in synchronous rectifier buck converters , 2000, APEC 2000. Fifteenth Annual IEEE Applied Power Electronics Conference and Exposition (Cat. No.00CH37058).

[4]  Horst Zimmermann,et al.  Nonlinear Current Control for Power Electronic Converters: IC Design Aspects and Implementation , 2013, IEEE Transactions on Power Electronics.

[5]  C. S. Mitter.  Device considerations for high current, low voltage synchronous buck regulators (SBR) , 1997, WESCON/97 Conference Proceedings.

[6]  Jungeui Park,et al.  Current-sensing technique for current-mode DC-DC buck converter with offset-voltage compensation , 2008, APCCAS 2008 - 2008 IEEE Asia Pacific Conference on Circuits and Systems.

[7]  Horst Zimmermann,et al.  A Bootstrap circuit for DC-DC converters with a wide input voltage range in HV-CMOS , 2016, 2016 39th International Convention on Information and Communication Technology, Electronics and Microelectronics (MIPRO).

[8]  Xi Hu,et al.  A novel on-chip current-sensing structure for current-mode DC-DC converter , 2013, 2013 International Symposium onVLSI Design, Automation, and Test (VLSI-DAT).

[9]  Ka Nang Leung,et al.  An integrated CMOS current-sensing circuit for low-Voltage current-mode buck regulator , 2005, IEEE Transactions on Circuits and Systems II: Express Briefs.

[10]  Horst Zimmermann,et al.  An integrated low power buck converter with a comparator controlled low-side switch , 2010, 13th IEEE Symposium on Design and Diagnostics of Electronic Circuits and Systems.

[11]  Johan Driesen,et al.  Analytical Switching Loss Model for Superjunction MOSFET With Capacitive Nonlinearities and Displacement Currents for DC–DC Power Converters , 2016, IEEE Transactions on Power Electronics.

[12]  Kuo-Hsing Cheng,et al.  A high-accuracy and high-efficiency on-chip current sensing for current-mode control CMOS DC-DC buck converter , 2008, 2008 15th IEEE International Conference on Electronics, Circuits and Systems.