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First-order allpass filters are analog filters with a unit magnitude response, but they change the phase shift between input and output signals at various frequencies. This paper presents the transadmittance-mode first-order allpass filters based on the modified current-controlled current differencing transconductance amplifier (M-CCCDTA). The proposed filters utilize a single M-CCCDTA and a grounded capacitor with no external resistors, making them well suited for implementation in an integrated circuit. The gain and phase response of the proposed filters can be adjusted electronically and separately. Also, the high output impedance of the proposed filters at both the input voltage node and the output current node makes cascading easy without the need for buffer devices. A quadrature sinusoidal oscillator based on the proposed first-order allpass filter has been designed as an example of an application. The PSpice simulation and actual experiments are utilized to validate the functionality of the proposed filters. The simulation and experimental results are consistent with the idea of anticipation. [ABSTRACT FROM AUTHOR]

Tunability of correlated color temperature (CCT) and dimmability are the two major sought after features of functional solid-state lighting. This paper presents a low-cost, efficient, single-inductor-dual-output buck driver that facilitates CCT-control and dimming of a light emitting diode (LED) module composed of cool-white and warm-white chips. The proposed driver is designed based on two familiar integrated circuits (ICs), namely LM2596 and NE556. LM2596 serves as the main switching regulator and amplitude modulation (AM) controller whereas NE556 serves as the constant-frequency, dual-output pulse-width-modulation (PWM) controller. The exponential model of LED is exploited for improved estimation of the design parameters of the LED module and the driver circuit. The developed driver prototype is tested for its electrical, photometric, and colorimetric performances. The driver offers a full-load efficiency of about 90% for a 12-W test LED module. Under different operating modes, the LED system can produce warm, cool, or neutral white light and at the same time, the produced illuminance can be varied over a wide range. Moreover, the light flicker is imperceptible since the PWM frequency is set according to IEEE-1789 guideline. [ABSTRACT FROM AUTHOR]