Modeling and Design Optimization of Capacitor Current Ramp Compensated Constant On-Time &lt;inline-formula&gt; 
                     &lt;tex-math notation="LaTeX"&gt;$V^{2}$&lt;/tex-math&gt;
                  &lt;/inline-formula&gt; Control

Yan, Yingyi; Lee, Fred C.; Tian, Shuilin; Liu, Pei‐Hsin

doi:10.1109/tpel.2017.2766259

Cited by 34 publications

(4 citation statements)

References 21 publications

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“…The describing function (DF) method stands out as the preeminent approach for deriving small signal models in PWM controllers, primarily attributed to its efficacy in addressing the nonlinearity inherent in pulse-width modulation (PWM) control schemes. Numerous small signal models [2], [9], [11]- [13], [15], [32] for COT control have been established through the describing function method. This methodology ensures the comprehensive inclusion of both sidebands associated with inductor current and capacitor voltage, extending the model's accuracy to the switching frequency.…”

Section: ) Control-to-output Transfer Function Of the Vrc-cotmentioning

confidence: 99%

A Voltage Ripple Compensation Method for Constant On-Time Buck Converter

He,

Liu,

Xia

et al. 2023

IEEE Access

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Subharmonic oscillation stands as a critical concern in the context of ripple-based constant-ontime (COT) controllers. While this issue can be mitigated through the application of the virtual inductor current (VIC) technique, it comes at the cost of load transient response. To achieve both high stability and rapid transient response, this paper introduces an Output Capacitor Voltage Ripple Compensation (VRC) technique. This technique minimizes the phase delay attributed to output capacitance by introducing a virtual output ripple (VVOR) inversely related to the feedback voltage. The VVOR serves to expedite the load transient response by counteracting the additional virtual inductor current injection during load transients. Utilizing a 0.13µm BCD technology, a synchronous buck converter is integrated with the proposed VRC-COT controller, showcasing exceptional stability across a load current range of 0 to 8A, even when equipped with a 30% 88µF ceramic output capacitor. Additionally, the load transient response exhibits reduced overshoot and undershoot, measuring at 120mV and 130mV, respectively, in response to load steps from 0A to 8A within a 10µS timeframe.INDEX TERMS Constant On-Time (COT), ripple-based control, voltage ripple compensation (VRC), equivalent series resistor (ESR), subharmonic oscillation.

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Section: ) Control-to-output Transfer Function Of the Vrc-cotmentioning

confidence: 99%

A Voltage Ripple Compensation Method for Constant On-Time Buck Converter

He,

Liu,

Xia

et al. 2023

IEEE Access

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“…Thus, it is ideal for voltage regulators powering the microprocessor, as microprocessors are in standby mode (i.e., light load) most of time [7]. Among various COT controls, the V 2 -COT control, as shown in Figure 1, has attracted much attention due to its fast transient performance and simple control circuit [8,9]. Notably, the COT control [10][11][12] or ripple-based COT control [13] is a special case of the V 2 -COT control, in which the error amplifier can be eliminated.…”

Section: Introductionmentioning

confidence: 99%

“…The essence of V 2 control with fast transient performance is that the output capacitor ESR is used to sense the capacitor current as the control signal for output voltage regulation [15]. Thus, using capacitor current as the compensation ramp can not only stabilize the V 2 -COT-controlled buck converter with small output capacitor ESR but can also improve its load transient performance [9]. In addition, some studies improved the load transient performance of the buck converter by introducing some auxiliary circuits during the transient operation; for instance, this was done by switching to a smaller inductor during the load transient operation [16] and by adding a load-side switched-capacitor-based converter during the load transient operation [17].…”

Section: Introductionmentioning

confidence: 99%

A Detection Circuit for Improving the Unloading Transient Performance of the COT Controller

2021

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Fast load transient response and high light-load efficiency are two key features of the constant on-time (COT) control technique that has been widely used in numerous applications, such as for voltage regulators and point-of-load converters. However, when load step-down occurs during an on-time interval, the COT controller cannot respond until the COT interval expires. This delay causes an additional output voltage overshoot, resulting in unloading transient performance limitation. To eliminate the delay and improve the unloading transient response of the COT controller, a load step-down detection circuit is proposed based on capacitor current COT (CC-COT) control. In the detection circuit, the load step-down is monitored by comparing the measured capacitor current with the preset threshold voltage. Once the load step-down is monitored, the on-time is promptly truncated and the switch is turned off. With the proposed detection circuit, the CC-COT-controlled buck converter can monitor the load step-down without any delay and obtain less output voltage overshoot when the load step-down occurs during the on-time interval. PSIM circuit simulations are employed to demonstrate the feasibility of the detection circuit.

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“…Therefore, a lot of control strategies are proposed for different DC-DC power converters. Among many strategies, the well-known V 2 controls have been widely used in industrial applications, and they can achieve a great control loop bandwidth [1][2][3]. Predictive controls acquire state variables ahead of time, which allow earlier actions to stabilize the system [4,5].…”

Section: Introductionmentioning

confidence: 99%

Linearized Discrete Charge Balance Control with Simplified Algorithm for DCM Buck Converter

et al. 2019

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In this paper, a linearized discrete charge balance (LDCB) control strategy is proposed for buck converter operating in discontinuous conduction mode (DCM). For DC-DC power converters, discrete charge balance (DCB) control is an attractive approach to improve the output voltage transient response. However, as a non-linear control strategy, the algorithm is complex, which is difficult for implementation. To reduce the complexity, this paper proposes the LDCB control strategy that is derived through linearizing conventional DCB controller. By deriving the differential functions of the DCB control algorithm, the small signal relationship between the input and output of DCB controller is explored. Furthermore, based on the relationship, the LDCB controller is formed through three parallel feed loops to the duty ratio. As a linear control approach, the achieved LDCB controller is greatly simplified for implementation. This not only saves the hardware cost, but also reduces the calculation lag, which provides potential to improve the switching frequency. Besides, since the LDCB controller shares the same small signal model as that of DCB controller, it achieves similar control loop bandwidth and transient performance. Effectiveness of the proposed LDCB control is verified by zero/pole plots, transient analyses and experimental results.

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Modeling and Design Optimization of Capacitor Current Ramp Compensated Constant On-Time <inline-formula> <tex-math notation="LaTeX">$V^{2}$</tex-math> </inline-formula> Control

Cited by 34 publications

References 21 publications

A Voltage Ripple Compensation Method for Constant On-Time Buck Converter

A Voltage Ripple Compensation Method for Constant On-Time Buck Converter

A Detection Circuit for Improving the Unloading Transient Performance of the COT Controller

Linearized Discrete Charge Balance Control with Simplified Algorithm for DCM Buck Converter

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