Esmaeel Ranjbar - Academia.edu (original) (raw)
Papers by Esmaeel Ranjbar
Microelectronics Journal, Aug 1, 2017
Abstract Many different compensation techniques have been proposed in the literature for today... more Abstract Many different compensation techniques have been proposed in the literature for today's low-voltage multi-stage integrated opamps. Each of them tries to optimize their proposed designing procedure considering desired characteristics such as: slow rate, DC gain, power consumption and unity gain-bandwidth. However, the existence of uncertainty in the parameters of the opamps or the compensation elements can affect the optimality of their responses. Variation of the capacitive load of a compensated opamp is one of the probable sources of uncertainty. As a matter of fact, different compensation topologies do not exhibit equal sensitivity to the variation of capacitive loads. Therefore; the selection of a proper compensation technique is considered as an important step when designing an opamp. In this paper, the goal is to study the existing compensation techniques and their behavior in the presence of load uncertainty. It is our goal to present a guide which helps to choose the suitable compensation topology considering the level of uncertainty in capacitive loads. To achieve these goals the structures are first designed for equal performance metrics such as: gain bandwidth product, phase margin and settling time. Then the sensitivity of the different structures is evaluated. Thereby, the least sensitive structures can be chosen as good candidates for realization. Based on the knowledge of the authors, no such thorough analysis has ever been performed before.
Microelectronics Journal, 2017
Abstract Many different compensation techniques have been proposed in the literature for today... more Abstract Many different compensation techniques have been proposed in the literature for today's low-voltage multi-stage integrated opamps. Each of them tries to optimize their proposed designing procedure considering desired characteristics such as: slow rate, DC gain, power consumption and unity gain-bandwidth. However, the existence of uncertainty in the parameters of the opamps or the compensation elements can affect the optimality of their responses. Variation of the capacitive load of a compensated opamp is one of the probable sources of uncertainty. As a matter of fact, different compensation topologies do not exhibit equal sensitivity to the variation of capacitive loads. Therefore; the selection of a proper compensation technique is considered as an important step when designing an opamp. In this paper, the goal is to study the existing compensation techniques and their behavior in the presence of load uncertainty. It is our goal to present a guide which helps to choose the suitable compensation topology considering the level of uncertainty in capacitive loads. To achieve these goals the structures are first designed for equal performance metrics such as: gain bandwidth product, phase margin and settling time. Then the sensitivity of the different structures is evaluated. Thereby, the least sensitive structures can be chosen as good candidates for realization. Based on the knowledge of the authors, no such thorough analysis has ever been performed before.
Integration, 2018
Using MOSCAPs for compensation can reduce the area needed for their implementation. However; thes... more Using MOSCAPs for compensation can reduce the area needed for their implementation. However; these capacitors are highly nonlinear and their value changes when the voltage across their terminals is changed. Different compensation topologies do not exhibit equal sensitivity to the time-dependent variation of MOSCAP compensation capacitors. Therefore; the selection of a proper compensation technique is considered as an important step before its implementation. In this paper, the goal is to study the existing compensation techniques and their behavior in the presence of compensation capacitor uncertainty and MOSCAP nonlinearity. For such regard, opamps are first designed for equal performance metrics such as: gain bandwidth product, phase margin and settling time. Then the sensitivities of the different structures are evaluated. Ultimately, the least sensitive structures can be chosen as the best choice for implementation. Based on the knowledge of the authors, no such thorough analysis has been ever performed before. A state-space model is suggested to analyze different compensation topologies and to calculate the harmonic distortions and find the most robust structures. These results are compared with circuit level results. It is shown that the CFCC compensation method can lead to creation of least harmonic distortion.
Microelectronics Journal, Aug 1, 2017
Abstract Many different compensation techniques have been proposed in the literature for today... more Abstract Many different compensation techniques have been proposed in the literature for today's low-voltage multi-stage integrated opamps. Each of them tries to optimize their proposed designing procedure considering desired characteristics such as: slow rate, DC gain, power consumption and unity gain-bandwidth. However, the existence of uncertainty in the parameters of the opamps or the compensation elements can affect the optimality of their responses. Variation of the capacitive load of a compensated opamp is one of the probable sources of uncertainty. As a matter of fact, different compensation topologies do not exhibit equal sensitivity to the variation of capacitive loads. Therefore; the selection of a proper compensation technique is considered as an important step when designing an opamp. In this paper, the goal is to study the existing compensation techniques and their behavior in the presence of load uncertainty. It is our goal to present a guide which helps to choose the suitable compensation topology considering the level of uncertainty in capacitive loads. To achieve these goals the structures are first designed for equal performance metrics such as: gain bandwidth product, phase margin and settling time. Then the sensitivity of the different structures is evaluated. Thereby, the least sensitive structures can be chosen as good candidates for realization. Based on the knowledge of the authors, no such thorough analysis has ever been performed before.
Microelectronics Journal, 2017
Abstract Many different compensation techniques have been proposed in the literature for today... more Abstract Many different compensation techniques have been proposed in the literature for today's low-voltage multi-stage integrated opamps. Each of them tries to optimize their proposed designing procedure considering desired characteristics such as: slow rate, DC gain, power consumption and unity gain-bandwidth. However, the existence of uncertainty in the parameters of the opamps or the compensation elements can affect the optimality of their responses. Variation of the capacitive load of a compensated opamp is one of the probable sources of uncertainty. As a matter of fact, different compensation topologies do not exhibit equal sensitivity to the variation of capacitive loads. Therefore; the selection of a proper compensation technique is considered as an important step when designing an opamp. In this paper, the goal is to study the existing compensation techniques and their behavior in the presence of load uncertainty. It is our goal to present a guide which helps to choose the suitable compensation topology considering the level of uncertainty in capacitive loads. To achieve these goals the structures are first designed for equal performance metrics such as: gain bandwidth product, phase margin and settling time. Then the sensitivity of the different structures is evaluated. Thereby, the least sensitive structures can be chosen as good candidates for realization. Based on the knowledge of the authors, no such thorough analysis has ever been performed before.
Integration, 2018
Using MOSCAPs for compensation can reduce the area needed for their implementation. However; thes... more Using MOSCAPs for compensation can reduce the area needed for their implementation. However; these capacitors are highly nonlinear and their value changes when the voltage across their terminals is changed. Different compensation topologies do not exhibit equal sensitivity to the time-dependent variation of MOSCAP compensation capacitors. Therefore; the selection of a proper compensation technique is considered as an important step before its implementation. In this paper, the goal is to study the existing compensation techniques and their behavior in the presence of compensation capacitor uncertainty and MOSCAP nonlinearity. For such regard, opamps are first designed for equal performance metrics such as: gain bandwidth product, phase margin and settling time. Then the sensitivities of the different structures are evaluated. Ultimately, the least sensitive structures can be chosen as the best choice for implementation. Based on the knowledge of the authors, no such thorough analysis has been ever performed before. A state-space model is suggested to analyze different compensation topologies and to calculate the harmonic distortions and find the most robust structures. These results are compared with circuit level results. It is shown that the CFCC compensation method can lead to creation of least harmonic distortion.