Browsing by Author "Huang, Hong-Wei"

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A 1-V, 16.9 ppm/degrees C, 250 nA Switched-Capacitor CMOS Voltage Reference
(2011-04-01)
Hsieh, Chun-Yu
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Huang, Hong-Wei
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Chen, Ke-Horng
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電控工程研究所
;
Institute of Electrical and Control Engineering
An ultra low-power, precise voltage reference using a switched-capacitor technique in 0.35-mu m CMOS is presented in this paper. The temperature dependence of the carrier mobility and channel length modulation effect can be effectively minimized by using 3.3 and 5V N-type transistors to operate in the saturation and subthreshold regions, respectively. In place of resistors, a precise reference voltage with flexible trimming capability is achieved by using capacitors. When the supply voltage is 1 V and the temperature is 80 degrees C, the supply current is 250 nA. The line sensitivity is 0.76%/V; the PSRR is -41 dB at 100 Hz and -17 dB at 10 MHz. Moreover, the occupied die area is 0.049 mm(2).
A programmable dual hysteretic window comparator
(2008)
Huang, Hong-Wei
;
Lin, Chia-Hsiang
;
Chen, Ke-Horng
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電控工程研究所
;
Institute of Electrical and Control Engineering
A programmable dual hysteretic window comparator is presented in this paper. The comparator uses a cascoded flipped voltage follower (CASFVF), a high speed V-I converter, and a current comparator to enhance the response time and accuracy. Moreover, the positive and negative hysteretic thresholds can be programmable, respectively. Simulation results in 0.25-mu m CMOS technology demonstrate the validity of the designed approach.
Adaptive frequency control technique for enhancing transient performance of DC-DC converters
(2007)
Huang, Hong-Wei
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Hsieh, Chun-Yu
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Chen, Ke-Horng
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Kuo, Sy-Yen
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電控工程研究所
An adaptive frequency control (AFC) technique is proposed for minimizing transient dropout voltage and response time of switching DC-DC converters. As we know, nonlinear fast-transient techniques with fixed switching frequency can effectively regulate the unstable output voltage back to steady-state within a short time. However, they suffer from oscillation problem because of large sourcing or sinking recovery current at output of error amplifier by fast transient circuit. Therefore, linear operation provided by AFC technique can dynamically and smoothly adjust the switching frequency, which is proportional to the output voltage variation, to regulate output voltage back to its steady-state value. In other words, AFC technique eliminates system and sub-harmonic oscillation scenarios. Experimental results demonstrate the transient dropout voltage is improved 37.8% when load current changes from 100 mA to 500 mA.
Built-in Resistance Compensation (BRC) Technique for Fast Charging Li-Ion Battery Charger
(2008)
Lin, Chia-Hsiang
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Huang, Hong-Wei
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Chen, Ke-Horng
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電控工程研究所
;
Institute of Electrical and Control Engineering
This paper presents a BRC technique to speed up the charging time of the Li-Ion battery. Based on the physical properties of the battery cell, the charger circuit charges the cell with three stages, which are trickle current (TC), constant current (CC), and constant voltage (CV) stages. Due to the internal parasitic resistance of the Li-Ion battery pack system, the charger circuit switches from the CC stage to the CV stage without fully charging the cell to the rated voltage value. At the CV stage, the cell is needed to be charged by a degrading current. The longer the cell stays at the CV stage, the longer the charging time is due to the degrading current. The BRC technique can dynamically estimate the internal resistance of the battery pack system to extend the period of the CC stage. The test chip was fabricated in TSMC 0.35-mu m process. Experimental results show the period of the CC stage can extended to about 40% that of the original design. The charging time can be effectively reduced.
Dithering skip modulation, width and dead time controllers in highly efficient DC-DC converters for system-on-chip applications
(2007-11-01)
Huang, Hong-Wei
;
Chen, Ke-Horng
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Kuo, Sy-Yen
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電控工程研究所
;
Institute of Electrical and Control Engineering
This paper proposes temperature-independent load sensor (LS), optimum width controller (OWC), optimum dead-time controller (ODC), and tri-mode operation to achieve high efficiency over an ultra-wide-load range. Higher power efficiency and wider loading current range require rethinking the control method for DC-DC converters.. Therefore, a highly efficient tri-mode DC-DC converter is invented in this paper for system-on-chip (SoC) applications, which is switched to sleeping mode at very light load condition or to high-speed mode at heavy load condition. The efficiency improvement is upgraded by inserting new proposed dithering skip modulation (DSM) between conventional pulse-width modulation (PWM) and pulse-frequency modulation (PFM). In other words, an efficiency-improving DSM operation raises the efficiency drop because of transition from PWM to PFM. Importantly, DSM mode can dynamically skip the number of gate driving pulses, which is inverse proportional to load current. Simplistically and qualitatively stated, the novel load sensor automatically selects optimum modulation method and power MOSFET width to achieve high efficiency over a wide load range. Moreover, optimum power MOSFET turn-on and turn-off delays in synchronous rectifiers and reduced ground bounce can save much switching loss by current-mode dead-time controller. Experimental results show the tri-mode operation can have high efficiency about 90% over a wide load current range from 3 to 500 mA. Owing to the effective mitigation of the switching loss contributed by optimum power MOSFET width and reduction of conduction loss contributed by optimum dead-times, the novel width and dead-time controllers achieve high efficiency about 95% at heavy load condition and maintain the highly efficient performance to very light load current about 0.1 mA.
Dithering skip modulator with a width controller for ultra-wride-load high-efficiency DC-DC converters
(2006-01-01)
Huang, Hong-Wei
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Ho, Hsin-Hsin
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Chien, Chieh-Ching
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Chen, Ke-Horng
;
Ma, Gin-Kou
This paper proposes a temperature-independent load sensor to decide the optimum power MOSFET width for power saving of DC-DC converters. Besides, it also can decide the optimum modulation technique in tri-mode operation, which is composed of pulse-width modulation (PWM), pulse-frequency modulation (PFM), and a new proposed dithering sldp modulation (DSM). An efficiency-improving DSM operation is introduced to raise the efficiency drop because of transition from PWM to PFM. Importantly, DSM mode can dynamically sldp the number of gate driving pulses, which is inverse proportional to load current. Simplistically and qualitatively stated, the novel load sensor can automatically select the optimum modulation method and optimum power MOSFET width to achieve high efficiency over a wide load range. Experimental results show the tri-mode operation can have high efficiency about 89 % over a wide load current range from 3mA to 500mA. Owing to the effective mitigation of the switching loss contributed by large power MOSFET, the novel width controller not only achieves high efficiency about 95 % but also extends this high efficiency to a lower load current range about 0.1mA.
Fast transient DC-DC converter with on-chip compensated error amplifier
(2006)
Huang, Hong-Wei
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Ho, Hsin-Hsin
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Chien, Chieh-Ching
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Chen, Ke-Horng
;
Ma, Gin-Kou
A novel fast transient DC-DC converter with on-chip compensated error amplifier is presented in this paper. The error amplifier uses on-chip current-mode Miller capacitor to replace a large off-chip capacitor. Only three transistors and one voltage follower are used to implement this novel architecture. Not only on-chip compensated error amplifier is implemented without off-chip components and I/O pins, but also it can have fast transient response. Furthermore, we accurately decrease the transient response time without suffering from the oscillation issue. Experimental results demonstrate the stability and the fast transient response of the DC-DC converters.
Fast Transient Technique (FTT) in Buck Current-Mode DC-DC Converters for Low-Voltage SoC Systems
(2008)
Lin, Chia-Hsiang
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Huang, Hong-Wei
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Chen, Ke-Horng
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電控工程研究所
;
Institute of Electrical and Control Engineering
This paper proposes a fast transient technique (FTT) to achieve excellent transient response of current-mode buck DC-DC converters. The proposed technique combines a non-linear control and a linear control mechanism to achieve fast transient response time, low output ripples, and stable transient operation at the same time. The test chip was fabricated in UMC 0.18-mu m process. Experimental results show that the transient undershoot/overshoot voltage and the recovery time are not exceed 48mV and 10 mu s, respectively.
Fast-transient dc-dc converter with on-chip compensated error amplifier
(2007-12-01)
Chen, Ke-Horng
;
Huang, Hong-Wei
;
Kuo, Sy-Yen
;
電控工程研究所
;
Institute of Electrical and Control Engineering
A fast-transient dc-dc converter with on-chip compensated error amplifier is presented in this paper. The error amplifier uses three transistors and one voltage follower to implement the on-chip current-mode Miller capacitor. Not only on-chip compensated error amplifier is implemented without off-chip components and I/O pins, but also fast-transient response Is achieved. Moreover, we accurately decrease the transient response time without suffering from the oscillation issue. Implemented in a 0.35-mu m CMOS process, experimental results demonstrate the stability of converters with a little area overhead about 5% larger than that of conventional design. In case of load variations, there is about four times reduction on the dropout voltage compared to that of conventional design. Furthermore, transient speed by our proposed technique is about five times faster than that of conventional control, while the total quiescent current is only increased about 3%.
High-Performance Low-Dropout Regulator Achieved by Fast Transient Mechanism
(2008)
Huang, Hong-Wei
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Lin, Chia-Hsiang
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Chen, Ke-Horng
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電控工程研究所
;
Institute of Electrical and Control Engineering
An adaptive reference control (ARC) technique is proposed for minimizing overshoot/undershoot voltage and settling time of low-dropout regulators (LDO). Linear operation provided by ARC technique can dynamically and smoothly adjust the reference voltage for increasing slew rate of error amplifier and forcing output voltage back to its steady-state value rapidly. The amount of transient revision is proportional to transient-state output voltage variation and load condition. In addition, dynamic push-pull technique is used to enhance transient response. Experimental results demonstrate the undershoot voltage, settling time and load regulation are improved 31%, 68.5% and 70% when load current changes between 1 mA and 100 mA.
Highly efficient tri-mode control of buck converters with load sensing technique
(2006)
Huang, Hong-Wei
;
Chien, Chieh-Ching
;
Chen, Ke-Horng
;
Kuo, Sy-Yen
;
電控工程研究所
A highly efficient tri-mode buck converter with a novel load sensor circuit is proposed in this paper. The combination of pulse-width modulation (PWM), pulse-frequency modulation (PFM) and pulse-skipping circuit makes it efficient to operate in wide loading region. By using the novel load sensor, the buck converter can achieve high efficiency for the load range from 3mA to 400mA. This load sensor can automatically switch the modes according to the different load conditions. It changes the modulation methods from PWM mode to pulse-skipping modulation mode or to PFM mode. This tri-mode buck converter is fabricated by TSMC 0.35um. The efficiency above 90% is achieved for the load range about 90-400mA in PWM operation, and above 78 % attained for the load range about 3-50m.A in PFM mode. The insertion of the pulse skipping mode operation extends the high efficiency 90% of PWM operation for the load range from 90mA down to 50mA.
Low-Dropout Regulators With Adaptive Reference Control and Dynamic Push-Pull Techniques for Enhancing Transient Performance
(2009-03-01)
Lin, Chia-Hsiang
;
Chen, Ke-Horng
;
Huang, Hong-Wei
;
電控工程研究所
;
Institute of Electrical and Control Engineering
An adaptive reference control (ARC) technique is proposed for minimizing overshoot/undershoot voltage and settling time of low-dropout regulators. Linear operation provided by the ARC technique can dynamically and smoothly adjust the reference voltage so as to increase the slew rate of error amplifier thus forcing the output voltage back to its steady-state value rapidly. The amount of transient revision is proportional to transient state output voltage variation and load condition. In addition, a dynamic push-pull technique is used to enhance transient response. Experimental results demonstrate that the undershoot voltage, settling time, and load regulation are improved by 31%, 68.5%, and 70%, respectively, when load current changes between 1 and 100 mA.
On-chip compensated error amplifier for fast transient DC-DC converters
(2006)
Huang, Hong-Wei
;
Ho, Hsin-Hsin
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Chang, Chia-Jung
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Chen, Ke-Horng
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Kuo, Sy-Yen
A novel on-chip compensated error amplifier for fast transient response of DC-DC converters is presented in this paper. The error amplifier uses on-chip current-mode Miller capacitor to replace a large off-chip capacitor. We only use three transistors and one voltage follower to implement this novel on-chip compensated error amplifier for fast transient DC-DC converters. Owing to the current-mode implementation, we can redirect the equivalent current to charge or discharge the output capacitor of the error amplifier to improve the transient response time. Not only on-chip compensated error amplifier is implemented without off-chip components and I/O pins, but also it can have fast transient response. The analytic equations guarantee the compensated correctness of the proposed circuit. With the proposed error amplifier, the transient response of DC-DC converters is improved significantly. Simulation results demonstrate the stability and the fast transient response of the DC-DC converters.
Programmable voltage-to-current converter with linear voltage control resistor
(2008)
Huang, Hong-Wei
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Hsieh, Wei-Lun
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Chen, Ke-Horng
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電控工程研究所
;
Institute of Electrical and Control Engineering
A programmable voltage-to-current converter with linear voltage control resistor (VCR) is presented in this paper. It uses a cascoded flipped voltage follower (CASFVF) to be the input stage in order to enhance the response time and accuracy. Programmability is achieved by using the control signal V-ctrl to adjust the equivalent resistance of VCR. Simulation results in 0.25-mu m CMOS technology demonstrate the high linearity of the proposed voltage-to-current converter and VCR circuit.
Single-inductor dual-output (SIDO) DC-DC converters for minimized cross regulation and high efficiency in SoC supplying systems
(2007)
Huang, Ming-Hsin
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Huang, Hong-Wei
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Peng, Jiun-Yan
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Tsai, Tzung-Ling
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Lee, Min-Chin
A compact size and high efficient single-inductor dual-output (SIDO) DC-DC converter is proposed. Generally speaking, it is important to implement DC-DC converters with minimized components and small footprint area. However, large external compensated resistors and capacitors are required to stabilize DC-DC converters. The proposed SIDO DC-DC converter not only provides dual output sources but also has minimized cross regulation without using any external compensated components. Importantly, our proposed mode-switch technique corrects the mistakes in the previous design [1], which didn't mention the unstable condition. Besides, owing to dynamically adjusting DC current level like CCM operation, the SH)O DC-DC converter achieves high conversion efficiency. Experimental results show a high efficiency from 85% at light load condition to 94% at heavy load condition.