Inverse Charge Constant On-Time Control With Ultrafast Transient Performance

Bari, Syed Mustafa Khelat; Li, Qiang; Lee, Fred C.

doi:10.1109/jestpe.2020.2973151

Cited by 12 publications

(6 citation statements)

References 13 publications

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“…Although in Tian et al, 15 an external ramp compensation solution is given to solve the multiphase ripple cancelation issue, the transient performance is limited by the slope of the external ramp. To solve this issue, the inverse charge constant on-time (IQCOT) control method is proposed in Bari et al, 16,17 which is different from CMCOT and V 2 control which are ripple-based schemes. The proposed IQCOT controller in 16,17 uses the combination of a transconductance amplifier and capacitor to do the integration of the sensed inductor current and realize COT control with no need for ripple information.…”

Section: Introductionmentioning

confidence: 99%

“…To solve this issue, the inverse charge constant on-time (IQCOT) control method is proposed in Bari et al, 16,17 which is different from CMCOT and V 2 control which are ripple-based schemes. The proposed IQCOT controller in 16,17 uses the combination of a transconductance amplifier and capacitor to do the integration of the sensed inductor current and realize COT control with no need for ripple information. Although this approach is an effective way to enhance the conventional constant on-time control and have good transient performance, the implementation of IQCOT control is harder than ripple-based COT control because of the extra transconductance amplifier and capacitor.…”

Section: Introductionmentioning

confidence: 99%

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Multiphase digital integration constant on‐time–controlled Buck converter with high‐resolution current balance scheme for ultrafast load transient

Li,

Xu,

Liu

et al. 2024

Circuit Theory & Apps

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SummaryIn this paper, a multiphase digital control called digital integration constant on‐time (DICOT) control is proposed, which applies the concept of signal accumulation, solves the drawbacks of ripple‐based digital COT control that the switching frequency and transient performance are affected by the A/D sample delay and sampling noise. Besides, the multiphase interleaving approach of the proposed DICOT control is well‐suitable for digital control and no higher calculation frequency is required compared to single‐phase. In the aspect of the current balance, almost all existing researches work on analog COT current balance scheme and few works are investigating the resolution improvement of digital COT current balance. In this paper, the current balance model of multiphase COT control is derived and can be applied in the Buck system with an arbitrary number of phases, the delay‐line‐based high‐resolution COT current balance scheme is proposed to enhance the control resolution. Finally, the two‐phase DICOT control is tested on the multiphase Buck system, the transient performance is tested of 100 A load step with the slew rate of 1000 A/μs, and the voltage undershoot and overshoot are 20 and 36 mV, respectively. The current balance is tested and the errors are 0.01% and 0.11% at the light and heavy loads, respectively.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Multiphase digital integration constant on‐time–controlled Buck converter with high‐resolution current balance scheme for ultrafast load transient

Li,

Xu,

Liu

et al. 2024

Circuit Theory & Apps

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“…To eliminate the effect of delay on the unloading transient performance, an effective scheme is to truncate on-time immediately when load step-down occurs [20]. Based on this idea, some methods are implemented [21][22][23]. In [21], Syed Bari et al proposed a new control strategy based on the current-mode COT control, in which the derivative of the output voltage was used to monitor the load step-down and truncated the on-time.…”

Section: Introductionmentioning

confidence: 99%

“…In [21], Syed Bari et al proposed a new control strategy based on the current-mode COT control, in which the derivative of the output voltage was used to monitor the load step-down and truncated the on-time. Furthermore, to avoid using an additional block of the derivative of the output voltage, an inverse charge COT control was proposed in [22]. The inverse-charge COT control employed the voltage difference of the sensed inductor current and the error voltage of the error amplifier to charge a capacitor.…”

Section: Introductionmentioning

confidence: 99%

“…In [23], the difference of the sensed inductor current and the output voltage of the error amplifier was compared with predefined thresholds to truncate the on-time when load step-down occurred. However, since the inductor current and capacitor voltage cannot be mutated, the methods in [22] and [23] could not truncate the on-time immediately, resulting in some delay. Therefore, it is necessary to further improve the detection speed [24].…”

Section: Introductionmentioning

confidence: 99%

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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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A Ramp Integrating Capacitor Current Constant On-time (RICCCOT) Controlled Buck Converter with High Noise Immunity in DCM

Chao,

Tsai,

Chen

et al. 2024

2024 IEEE Applied Power Electronics Conference and Exposition (APEC)

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Inverse Charge Constant On-Time Control With Ultrafast Transient Performance

Cited by 12 publications

References 13 publications

Multiphase digital integration constant on‐time–controlled Buck converter with high‐resolution current balance scheme for ultrafast load transient

Multiphase digital integration constant on‐time–controlled Buck converter with high‐resolution current balance scheme for ultrafast load transient

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

A Ramp Integrating Capacitor Current Constant On-time (RICCCOT) Controlled Buck Converter with High Noise Immunity in DCM

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