Publications

[60] J.Kim, T.Guo, Q.Duan, J.Moon, Y.Kim, and J.Roh, "Ultralow-Power ECG Monitoring Sensor Based on a Continuous-Time Delta-Sigma Modulator With an On-Chip PMIC", IEEE Transactions on Instrumentation and Measurement, vol. 74, pp. 1-6, Mar. 2025.

[59] J. Choi et al., "High-Precision Built-In Phase Noise Measurement Circuit With a Hybrid ΔΣ Time-to-Digital Converter for SoC Clocking Applications," IEEE Transactions on Circuits and Systems II: Express Briefs, vol. 71, no. 11, pp. 4613-4617, Nov. 2024

[58] J. S. Kim, S. Ha, H. Jeong and J. Roh, "A High-PSRR NMOS LDO Regulator With Intrinsic Gain-Tracking Ripple Cancellation Technique," IEEE Transactions on Circuits and Systems I: Regular Papers, vol. 71, no. 11, pp. 4951-4960, Nov. 2024

[57] H. Shin, S. Song, H. Jeong, Q. Duan, and J. Roh, "Automatic Tuning of Negative-R Circuit for High-Performance 95-dB DR 5-kHz Bandwidth Continuous-Time Delta-Sigma Modulator", IEEE Transactions on Circuits and Systems I, Regular Papers, vol. 71, no. 6, pp. 2473-2482, June 2024

[56] T. Kim, B. Kim and J. Roh, "A 54-nA Quiescent Current Capless LDO With −39-dB PSRR at 1 MHz Using a Load-Tracking Bandwidth Extension Technique," IEEE Transactions on Circuits and Systems II, vol. 71, no. 3, pp. 1556-1560, March 2024.

[55] J. Kim, K. Javed, and J. Roh, "Design of a Low-Power and Area-Efficient LDO Regulator Using a Negative-R Assisted Technique", IEEE Trans. Circuits and Systems ll, vol. 70, no. 10, pp. 3892-3896, Oct. 2023.

[54] H. Shin, Q. Duan, J. Kim, S. Na, and J. Roh, "103.1-dB DR Switched-Resistor Delta-Sigma Modulator With Chopped Negative-R for Suppressing Low-Bandwidth Noise", IEEE Access, vol. 11, pp. 104244-104252, Sep. 2023.

[53] J. Kim, K. Javed, K. Min, and J. Roh, "A 13.5-nA Quiescent Current LDO with Adaptive Ultra-Low-Power Mode for Low-Power IoT Applications", IEEE Trans. Circuits and Systems ll, vol. 70, no. 9, pp. 3278-3282, Sep. 2023.

[52] T. Guo, Q. Duan, M. Lee, and J. Roh, "A 464-nA Quiescent Current Buck Converter with 93.7% Peak Efficiency for IoT Devices", IEEE Trans. Industrial Electronics, Aug. 2023.

[51] J. Moon, J. Lee, K. Javed, J. Hong, and J. Roh, "Concurrent Current and Voltage Regulated Buck–Boost Converter for Automotive LED Matrix Headlights", IEEE Trans. Power Electronics, vol. 38, no. 5, pp. 6015-6023, May. 2023.

[50] J. Kim, Q, Duan, J. Choi, C, Song, and J. Roh, "A 2.16 µW Low-Power Continuous-Time Delta-Sigma Modulator with Improved-Linearity Gm for Wearable ECG Application", IEEE Trans. Circuits and Systems ll, vol. 69, no. 11, pp. 4223-4227, Nov. 2022.

[49] T. Guo, W. B. Kang, and J. Roh, "A 0.9 µA Quiescent Current High PSRR Low Drop Out Regulator With Capacitive Feed Forward Ripple Cancellation Technique", IEEE Journal of Solid-State Circuits, vol. 57, no. 10, pp. 3139-3149, Oct. 2022.

[48] J. Tang, T. Guo, J. Kim, and J. Roh, "A Current-Mode Four-Phase Synchronous Buck Converter with Dynamic Dead-Time Control", IEEE Access, vol. 9, pp. 81078-81088, Jun. 2021.

[47] I. Jeon, T. Guo, and J. Roh, "300 mA LDO Using 0.94 μA IQ With an Additional Feedback Path for Buffer Turn-off Under Light-Load Conditions", IEEE Access, vol. 9, pp. 51784-51792, Mar. 2021.

[46] S. Song, J. Kim, and J. Roh, "100.5 dB SNDR Analog Front-End With a Resistor-Based Discrete-Time Delta-Sigma Modulator for Eliminating Switching Noise and Harmonics", IEEE Access, vol. 9, pp. 39852-39863, Mar. 2021.

[45] J. Kim, S. Song, and J. Roh, "A High Slew-Rate Enhancement Class-AB Operational Transconductance Amplifier (OTA) for Switched-Capacitor (SC) Applications", IEEE Access, vol. 8, pp. 226167-226175, Dec. 2020.

[44] J. Moon, J. Lee, S. Kim, G. Ryu, J. Hong, J. Lee, H. Jin, and J. Roh, "60-V Non-Inverting Four-Mode Buck-Boost Converter With Bootstrap Sharing for Non-Switching Power Transistors", IEEE Access, vol. 8, pp. 208221-208231, Nov. 2020.

[43] J. Lee, S. Song, and J. Roh, "A 5-MHz Bandwidth 78.1-dB SNDR 2-2 MASH Delta-Sigma Modulator", International Journal of Electronics, vol. 107, no. 4, pp. 613-629, Oct. 2019.

[42] J. Lee, S. Song, and J. Roh, "A 103-dB DR Fourth-Order Delta-Sigma Modulator for Sensor Applications", Electronics, 2019, 8, 1093, Sep. 2019.

[41] S. Song, J. Lee, and J. Roh, "A 20-MHz Bandwidth, 75-dB Dynamic Range, Continuous-Time Delta-Sigma Modulator with Reduced Nonidealities", International Journal of Circuit Theory and Applications, Jun. 2019.

[40] J. Tang, J. Lee, and J. Roh, "Low-Power Fast-Transient Capacitor-less LDO Regulator with High Slew-Rate Class-AB Amplifier", IEEE Trans. Circuits and Systems II, vol. 66, no. 3, pp. 462-466, Mar. 2019 .

[39] K. Javed, J. Yeo, J. Lee, and J. Roh, "Fast-transient DC-DC converter using a high-performance error amplifier with a rapid output-voltage control technique", International Journal of Circuit Theory and Applications, vol. 45, no. 10, pp. 1431-1438, Oct. 2017.

[38] Y. Jung, Q. Duan, and J. Roh, "A 17.4-bit Delta-Sigma Capacitance-to-Digital Converter for One-Terminal Capacitive Sensors", IEEE Trans. Circuits and Systems II, vol. 64, no. 10, Oct. 2017.

[37] J. Yeo, K. Javed, J. Lee, J. Roh, and J. Park, "A capacitorless low-dropout regulator with enhanced slew rate and 4.5-uA quiescent current", Analog Integrated Circuits and Signal Processing, vol. 90, no. 1, pp. 227-235, Jan. 2017.

[36]  Q. Duan, Y. Jung, D. Choi, J. Roh, and J. Kim, "A 1.2 V 83 dB DR single-ended input SC ΔΣ modulator including a large-swing analog buffer for portable ECG applications", International Journal of Circuit Theory and Applications, vol. 44, no. 12, pp. 2164-2173, Dec. 2016.

[35]  Y. Yoon, Q. Duan, J. Yeo, J. Roh, J. Kim, and D. Kim, "A Delta-Sigma Modulator for Low-Power Analog Front Ends in Biomedical Instrumentation", IEEE Trans. Instrumentation and Measurement, vol. 65, no. 7, pp. 1530-1539, Jul. 2016.

[34]  Q. Duan, Z. Wang, and J. Roh, "A 7.5-µW 0.08-mm^2 Single-Ended SC Delta-Sigma ADC for Acoustic Sensor Applications", International Journal of Circuit Theory and Applications, vol. 44, no. 5, pp. 1173-1185, May 2016.

[33] Y. Yoon, D. Choi, and J. Roh, "A 0.4 V 63 µW 76.1 dB SNDR 20 kHz Bandwidth Delta-Sigma Modulator Using a Hybrid Switching Integrator", IEEE Journal of Solid-State Circuits, vol. 50, no. 10, pp. 2342-2352, Oct. 2015.

[32] Z. Wang, Y. Jung, and J. Roh, "A 10-MHz Multi-bit MASH Delta–Sigma Modulator with Analog Summing Interstage", Analog Integrated Circuits and Signal Processing, vol. 85, no. 1, pp. 201-207, Oct. 2015.

[31] Q. Duan, and J. Roh, "A 1.2-V 4.2-ppm/C High-Order Curvature-Compensated CMOS Bandgap Reference", IEEE Transactions on Circuits and Systems I, vol. 62, no. 3, pp. 662-670, Mar. 2015.

[30] Y. Ahn, I. Jeon, and J. Roh, "A Multiphase Buck Converter With A Rotating Phase-Shedding Scheme For Efficient Light-Load Control", IEEE Journal of Solid-State Circuits, vol. 49, no. 11, pp. 2673-2683, Nov. 2014.

[29] Z. Wang, Q. Duan, and J. Roh, "A 0.03 mm^2 Delta-Sigma Modulator with Cascaded-Inverter Amplifier", Analog Integrated Circuits and Signal Processing, vol. 81, no. 2, pp. 495-501, Nov. 2014.

[28]  Y. Ahn, I. Jeon, and J. Roh, "A Multiple-Output Switched-Capacitor DC-DC Converter for Individual Brightness Control of RGB LEDs with Time-Interleaved Control and Output Current Regulation",  Analog Integrated Circuits and Signal Processing, vol. 79, no. 2, pp. 345-354, May 2014

[27]  Y. Yoon, H. Roh, and J. Roh, "A True 0.4 V Delta-Sigma Modulator Using a Mixed DDA Integrator Without Clock Boosted Switches ",  IEEE Transactions on Circuits and Systems II, vol. 61, no. 4, pp. 229-233, Apr. 2014.

[26] J. Yeo, et. al , "A Current Regulator for Inverter-Based Massively Column-Parallel ΔΣ ADCs ",  IEEE Transactions on Circuits and Systems II, vol. 61, no. 4, pp. 224-228, Apr. 2014. 

[25] Y. Jung, Q. Duan, and J. Roh, "A single-electrode capacitive sensor using incremental delta-sigma architecture", Analog Integrated Circuits and Signal Processing, vol. 76, no. 2, pp. 261-265, Aug. 2013. 

[24] Y. Jung, H. Roh, and J. Roh, "An Input-Feedforward Multibit Adder-Less Δ- Σ  Modulator for Ultrasound Imaging Systems", IEEE Trans. Instrumentation and Measurement, vol. 62, no. 8, pp. 2215-2227, Aug. 2013. 

[23] I. Jeon, H. Nam, H. Lee, Y. Ahn, and J. Roh, "An 80-V integrated boost converter for piezoelectric actuators in smartphones", Analog Integrated Circuits and Signal Processing, vol. 75, no. 3, pp. 531-537, Jun. 2013. 

[22] Y. Yoon, H. Roh, H. Lee, and J. Roh, "A 0.6-V 540-nW Delta-Sigma Modulator for Biomedical Sensors", Analog Integrated Circuits and Signal Processing, vol. 75, pp. 323-327, May 2013.  

[21] Y. Ahn, H. Nam, and J. Roh, "A 50-MHz Fully-Integrated Low-Swing Buck Converter Using Packaging Inductors", IEEE Transactions on Power Electronics, vol. 27, no. 10, pp. 4347-4356, Oct. 2012. 

[20] H. Nam, Y. Ahn, and J. Roh, "A Buck Converter with Adaptive On-Time PFM Control and Adjustable Output Voltage", Analog Integrated Circuits and Signal Processing, vol. 71, pp. 327-332, May 2012.

[19] Y. Choi, W. Tak, Y. Yoon, J. Roh, S. Kwon, and J. Koh, "A 0.018% THD+N, 88dB PSRR PWM Class-D Amplifier for Direct Battery Hookup", IEEE Journal of Solid-State Circuits, vol. 47,  no. 2, pp. 454-463,  Feb. 2012.

[18]  Y. Choi, H. Roh, and J. Roh,  "A Bufferless Interface for Single-ended ECM Sensors",  IEEE Trans. Instrumentation and Measurement, vol. 61, no. 2, pp. 513-520, Feb. 2012.

[17] H. Nam, Y. Ahn, and J. Roh,  "5-V buck converter using 3.3-V standard CMOS process with adaptive power transistor driver increasing efficiency and maximum load capacity",  IEEE Transactions on Power Electronics., vol. 27, no. 1, pp. 463-471, Jan. 2012.

[16] Y. Ahn, D. Heo, H. Nam, and J. Roh,  "A 400-mA Current-Mode Buck Converter with Self-Trimming Current Sensing Scheme",  Analog Integrated Circuits and Signal Processing, vol. 66, pp. 163-170, Feb. 2011.

[15] H. Roh, Y. Choi, and J. Roh,  "A 89-dB DR 457-uW 20kHz bandwidth delta-sigma modulator with gain-boosting OTAs",  Analog Integrated Circuits and Signal Processing, vol. 64, pp. 173-182, Aug. 2010.

[14] H. Roh, S. Byun, Y. Choi, and J. Roh,  "Fully synthesised decimation filter for delta-sigma A/D converters",  International Journal of Electronics, vol. 97, No. 6, pp. 663-676, Jun. 2010.

[13] H. Roh, H. Lee, Y. Choi, and J. Roh,  "A 0.8-V 816-nW Delta-Sigma Modulator for Low-Power Biomedical Applications",  Analog Integrated Circuits and Signal Processing, vol. 63, pp. 101-106, Apr. 2010.

[12]  H. Nam, I. Kim, Y. Ahn, and J. Roh,  "DC-DC Switching Converter with Positive and Negative Outputs for active-matrix LCD Bias",  IET Circuits Devices Systems., Mar. 2010.

[11]  H. Roh, H. Kim, Y. Choi, J. Roh, Y. Kim, and J. Kwon,  "A 0.6-V Delta-Sigma Modulator with Subthreshold-Leakage Suppression Switches",  IEEE Trans. Circuits and Systems II, Nov. 2009.

[10]  Y. Choi, J. Roh, H. Roh, H. Nam, S. Lee,  "A 99-dB DR Fourth-Order Delta–Sigma Modulator for 20-kHz Bandwidth Sensor Applications",  IEEE Trans. Instrumentation and Measurement., vol. 58, no. 7, pp. 2264-2274, Jul. 2009.

[9]  K. Kang, J. Roh, Y. Choi, H. Roh, H. Nam, and S. Lee,  " Class-D Audio Amplifier Using 1-Bit Fourth-Order Delta-Sigma Modulation",  IEEE Trans. Circuits and Systems-II, vol. 55, no. 8, pp. 728-732, Aug. 2008.

[8] J. Roh, S. Byun, Y. Choi,  H. Roh, Y. Kim and J. Kwon,  " A 0.9-V 60uW 1-bit 4th-order delta-sigma modulator with 83-dB dynamic range",  IEEE J. Solid-State Circuits, vol. 43, no. 2, pp. 361-370,  Feb. 2008.

[7]  J. Roh,  "Digital PWM controller with one-bit noise-shaping interface",  Analog Integrated Circuits and Signal Processing, vol. 49, pp.11-17, Jun. 2006.

[6]  J. Roh,  "High-Gain Class-AB OTA with Low quiescent Current",  Analog Integrated Circuits and Signal Processing, vol.47, No.2, pp.225-228, Mar. 2006.

[5]  J. Roh,  "Analogue-to-digital interface technique for digital controllers in DC-DC converters",  IEE Electronics Letters, vol. 41, no. 18, pp.1034-1036, Sep. 2005.

[4]  J. Roh,  "High-performance error amplifier for fast transient DC-DC converters",  IEEE Trans. on Circuits and Systems-II, vol. 52. no. 9, pp. 591-595, Sep. 2005.

[3]  J. Roh, Jacob A. Abraham,  "Subband filtering for time and frequency analysis of mixed-signal circuit testing",  IEEE Trans. Instrumentation and Measurement, vol. 53, no. 2, pp. 602-611, Apr. 2004.

[2]  J. Roh, Jacob A. Abraham, " A comprehensive signature analysis scheme for oscillation-test", IEEE Trans. Computer-Aided Design, vol. 22, no. 10, pp.1409-1423, Sep. 2003.

[1]  J. Roh, S.Lee, and S. Park, "Digital PWM controller for DC-DC converters with minimum analogue circuits", IEE Electronics Letters, vol. 39, no. 19, pp. 1402-1403, Sep. 2003.

[16] T. Guo, J. Moon, J. Roh, "A Power Supply Rejection Compensated External Capacitor-less Low Drop-out Regualtor", 2019 International SoC Design Conference (ISOCC), pp.54-55, Oct. 2019.

[15] H. Roh, Q. Duan, and J. Roh, "All MOS Transistors Bandgap Reference Using Chopper Stabilization Technique", ISOCC 2010,  pp.353-357, Nov. 2010.

[14] H. Nam, D. Lee, Y. Ahn, and J. Roh, "Adaptive Ramp Generation for Enhanced Stability of a Current-Mode PWM Buck Converter", CEWIT 2010,  Sep. 2010

[13] Y. Ahn, H. Nam, and J. Roh, "A 93.5% efficiency, 400-mA current-mode DC-DC buck converter with watchdog functions", IEEE ISOCC 2009, pp. 428-431, Nov. 2009.

[12] Y. Choi, H. Kim, H. Roh, J. Roh, "A 290-μW 25-kHz Continuous-Time Delta-Sigma Modulator for Acoustic Sensor Networks", IEEE ASICON 2009 , pp. 447-450 , Oct. 2009.

[11] Y. Ahn, K. Kim, H. Nam, Y. Choi, H. Roh, and J. Roh, " Design of buck converter circuits operating in weak-inversion region", IEEE IDT , pp. 104-108, Dec. 2008.

[10] D. Lee, H. NAM, Y. Ahn and J. Roh, "1.5Mhz, 300mA step-down switching regulator", ISOCC 2008, vol. 03, pp. 50-51, Nov. 2008.

[9] H. Nam, I. Kim, Y. Ahn, and J. Roh, "A high efficiency boost converter for TFT-LCD bias supply", ITC-CSCC 2008, pp. 1025-1028, Jul. 2008.

[8] Y. Ahn, D. Heo, H. Nam, and J. Roh, "An inductor-type current-mode buck converter for mobile applications", ITC-CSCC 2008, pp. 985-988, Jul. 2008.

[7] Youngkil Choi, Hyungdong Roh, Hyunseok Nam, and Jeongjin Roh, "99-dB high-performance delta-sigma modulator for 20-kHz bandwidth", in Proc. DELTA 2008,  pp. 75-78, Jan. 2008.

[6] Hyungdong Roh, Sanho Byun, Seongyoung Ryu, Youngkil Choi, Hyunseok Nam, and Jeongjin Roh, "Design of Digital Decimation Filter for Delta-Sigma A/D Converters,” ITC-CSCC 2007, pp.595-596, Jul. 2007.

[5] Youngkil Choi, Hyungdong Roh, Hyunseok Nam, and Jeongjin Roh, “Design of a 99-dB DR Single-bit Fourth-order High-performance Delta-Sigma Modulator,” ITC-CSCC 2007,  pp.29-30, Jul. 2007.

[4] Kyoungsik Kang, Youngkil Choi, Hyungdong Roh, Sanho, Hyuntae Lee, and Jeongjin Roh, “A 80%-Efficiency Digital Audio Amplifier with 4-ohm Speaker Load Using 1-bit 4th-Order Delta-Sigma Modulation,” 2006 IEEK International SoC Design Conference, pp.95-98, Oct. 2006.

[3] Jeongjin Roh, Donghun Heo, Kitae Kim, Hyunseok Nam and Hyungdong Roh, “A 900nA quiescent current Buck converter with on-chip compensator,” ITC-CSCC 2006, pp.413-416, Jul. 2006.

[2] Youngkil Choi, Wanki Hong, Kitae Kim, Insuk Kim, and Jeongjin Roh, “Design of a fast DC-DC Boost converter,” 2005 IEEK International SoC Design Conference, pp.95-98, May 2005.

[1] Wanki Hong, Kitae Kim, Youngkil Choi, Seongyoung Ryu, Insuk Kim, Hyungdong Roh,  Sanho Byun, and Jeongjin Roh, “Delta-Sigma Modulation for Digital DC-DC Controllers,” ITC-CSCC 2005, pp.1047-1048, Jun. 2005.