This paper presents 1V supply voltage Bi-CMOS current mode circuits. The circuits are consist of current mirrors, current comparators and current sources. The circuits have some advantages such as high accuracy, high speed, high density and low power supply. As an application of the circuits, an analog-to-digital converter (ADC) is given. The ADC operates with small chip area and low power dissipation. The performances of the proposed circuits were confirmed by using SPICE2 simulation.

A CMOS fully balanced current-mode filter is presented. A fully balanced current-mode integrator which is the basic building block is implemented by adding a very simple common-mode-rejection mechanism to fully differential one. The fully balanced operation can eliminate even order distortion, which is one of the drawbacks in previous continuous current-mode filter. Moreover, the additional circuit can work as not only common-mode-rejection mechanism but also Q-tuning circuit which compensates lossy elements due to finite output impedance of MOS FET. A prototype fifth-order low-pass lad-der filter designed in a standard digital 0.8µm CMOS process achieved a cut-off frequency (fC) of 100MHz; fC was tunable from 75MHz to 120MHz by varying a reference bias current from 50µA to 150µA. Using a single 3V power supply with a nominal reference current of 100µA, power dissipation per one pole is 30mW. The active filter area was 0.011mm2/pole and total harmonic distortion (THD) was 0.73 [%] at 80MHz, 80µA amplitude signal. Furthermore, by adjusting two bias currents, on chip automatic both frequency and Q controls are easily implemented by typical tuning systems, for example master-slave tuning systems [1].

Recently, the clean electric power generation systems have been developed aggressively to exploit the clean energy resources such as solar array, fuel cell and so forth. In this case, the multiple-input dc-dc converter is useful to combine the multiple input power sources and to take the appropriate amount of power from these multiple input power sources, in which their voltage levels and/or their power capacities are different. We have proposed a novel multiple-input dc-dc converter, in which the distinctive feature is its simpler circuit configuration in comparison with that in parallel with the multiple converters. This paper presents two control methods for the two-input dc-dc converter. In the first control method, the on-time of one switch is determined only by the input current and that of another one is controlled by both of the input current and the output voltage. On the other hand, in the second control method, though the on-time of one switch is determined only by the input current as well as in the first control method, the on-time of the another switch is controlled only by the output voltage. The comparative analysis of the steady-state and dynamic characteristics of the two-input dc-dc converter using two control methods are performed theoretically and experimentally. As a result, it is revealed that the first control method is superior to the second one in the steady-state and dynamic performances.

This paper presents the analysis of a new multi-oscillated current resonant type DC-DC converter. Current resonant converters have several remarkable features such as high efficiency, small size, low cost and low noise, and are frequently employed in many portable electronic systems such as personal computers, cellular phones and flat panel displays. The current resonant type converter generally employs pulse frequency modulation for constant voltage control in the output. For this reason, the magnetizing current through the converter not only causes a power loss under a light load, but also a loss during stand-by. Therefore, this type of converter has a problem in that the required smaller size cannot be achieved, because an auxiliary source is necessary for stand-by. In order to solve these problems, a new current resonant type power supply is proposed in which two driving methods are employed. In these driving methods, one MOSFET as a main switch is driven by an auxiliary winding of the transformer and another MOSFET as a main switch is driven by the driving IC with a low withstand voltage. Good agreement of the observed and simulated waveforms was confirmed. In addition, eight distinct states and four distinct operating modes, which compose of the sequence of states, were clarified by experimental and simulated analysis.

This paper presents the novel method not only to suppress the input current harmonics but also to realize the low frequency output voltage ripple using the multiple-input ac-dc converter, which is considered from viewpoints of the relatively small power application and simple circuit configuration. The operation principle and control strategy of the proposed circuit are discussed. As a result, it is clarified that the new circuit has excellent performance characteristics such as high power factor over 0.99, low total harmonic current distortion factor less than 9.2% and low output voltage ripple of 40 mV.