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SUMMARYIn this paper, four different-type second-order current-mode filters, employing second-generation currentcontrolled conveyors (CCCIIs) and two capacitors, are proposed. The first two of the presented filters can simultaneously realize high-output impedance low-pass, band-pass and high-pass responses. Also, the two filters can provide notch and all-pass filter responses with interconnection of the relevant output currents. The first developed one needs no critical active and passive element matching conditions and/or cancellation constraints. The second and third introduced ones employ only grounded capacitors. The fourth proposed filter derived from the third one uses only plus-type single output CCCIIs (CCCII+s). The fifth filter can be constructed using commercially available active devices such as AD844s along with additional resistors instead of CCCII+s of the fourth proposed filter to perform experimental test easily. All of the proposed filters have low active and passive element sensitivities. Time and frequency domain analyses are performed for the first, second and third realized filters using SPICE simulation program. Also, experimental test is achieved for the fifth filter. In this study, stability problems attributed to non-ideal gains of the CCCIIs and signal limitations of the first, second and third introduced filters due to restricted power supply voltages are investigated.

A new log‐domain first‐order multifunction filter is proposed in this letter. The proposed filter is systematically derived using the state‐space synthesis procedure from a corresponding block diagram. It provides low‐pass (LP), high‐pass (HP), and all‐pass (AP) responses simultaneously for a single input signal. The filter circuit has a very simple structure since it uses only bipolar junction transistors (BJTs) and a grounded capacitor. It can be electronically tuned by changing an external current. The filter has a greater bandwidth due to its inherent current‐mode and log‐domain operations. PSPICE simulations are given to confirm the theoretical analysis.

Generating electrical power from solar energy is very popular. There are many studies aiming at increasing the efficiency and designing simpler systems. Electrical power generated by PV cells depends on solar irradiances, ambient temperatures and electrical loads. To transfer maximum available power from PV cells to the grid, Maximum Power Point Tracker (MPPT) algorithms have been developed and implemented. In this study, a simpler single-phase single-stage grid connected system has been designed and analysed. The proposed circuit does not require complex circuitries and modulation techniques. A 175 Watt prototype system is implemented. Under different environmental conditions, the control unit forces the system to operate at the maximum available power.

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