A semiconductor switching device or amplifier combined in parallel with one or more active devices defined as starter devices. A starter device is used to reduce the terminal voltage of a switching device or amplifier to a dc level below about 0.4 volts which will then allow the switching device to easily change between the on or conducting state and the off or non-conducting state. Three different starter devices are utilized. The first being a Bipolar Junction Transistor (BJT), the second a Metal Oxide Silicon Field Effect Transistor (MOSFET), and the third consisting of three normally off JFETs connected serially. Generally, a single starter device is coupled across the terminals of a semiconductor switching device or amplifier, but it is possible and sometimes advantageous to couple two or more starter devices in parallel. In a first case, a symmetrical, normally off or enhancement mode JFET is used as the switch or amplifier. A starter device coupled between source and drain of the JFET will allow operation at dc voltage levels above 0.4 volts. In a second case, an asymmetrical, normally off JFET is used as the switch or amplifier. A starter device coupled between source and drain of the JFET will allow operation at dc voltage levels above 0.4 volts. In a third case, a normally off MESFET is used as the switch or amplifier. A starter device coupled between source and drain of the MESFET will allow operation at dc voltage levels above 0.4 volts.

The invention is related to methods and apparatus for driving transistors. One embodiment includes a driver circuit that can drive power transistors at relatively high switching speeds, which can advantageously decrease the size of associated electronics systems that use the driver circuit and power transistors. Embodiments of the invention can drive a switching device that needs a negative voltage bias in order to be shut off. For example, the switching device can correspond to a junction field effect transistor (JFET). Advantageously, one embodiment of the invention can drive such switching devices on and off from a single positive voltage supply.

A four terminal full wave rectifier circuit that can be used as a pin for pin replacement for the full wave diode rectifier circuit commonly used in DC power supply circuits. Two full wave rectifier circuits that can efficiently supply the DC currents required in both discrete and integrated circuits being operated at low DC supply voltages are disclosed. Both circuits utilize two n-channel, enhancement mode Junction Field Effect Transistors (JFET) and two p-channel, enhancement mode Junction Field Effect Transistors to replace the rectifier diodes used in a conventional full wave rectifier circuit. The forward voltage drop across each JFET is considerably smaller than the forward voltage drop of a conventional rectifier. In a first configuration, the JFETs are all symmetrical about the source and drain leads. Starter devices are connected between source and drain leads and current limiting devices are in series with the gate leads. The gate leads of the JFETs are connected to the input terminals of the circuit such that a full wave rectified version of the input signal is produced at the output of the circuit. In a second configuration, two asymmetrical n-channel and two asymmetrical p-channel JFETs are used to replace the four rectifier diodes found in a conventional full wave rectifier circuit. The gate of each JFET is connected to its source lead and a full wave rectified version of the input signal is then produced at the output of this circuit.

A semiconductor switching device or amplifier combined in parallel with one or more active devices defined as starter devices. A starter device is used to reduce the terminal voltage of a switching device or amplifier to a dc level below about 0.4 volts which will then allow the switching device to easily change between the on or conducting state and the off or non-conducting state. Three different starter devices are utilized. The first being a Bipolar Junction Transistor (BJT), the second a Metal Oxide Silicon Field Effect Transistor (MOSFET), and the third consisting of three normally off JFETs connected serially. Generally, a single starter device is coupled across the terminals of a semiconductor switching device or amplifier, but it is possible and sometimes advantageous to couple two or more starter devices in parallel. In a first case, a symmetrical, normally off or enhancement mode JFET is used as the switch or amplifier. A starter device coupled between source and drain of the JFET will allow operation at dc voltage levels above 0.4 volts. In a second case, an asymmetrical, normally off JFET is used as the switch or amplifier. A starter device coupled between source and drain of the JFET will allow operation at dc voltage levels above 0.4 volts. In a third case, a normally off MESFET is used as the switch or amplifier. A starter device coupled between source and drain of the MESFET will allow operation at dc voltage levels above 0.4 volts.

The use of an alternating current (ac) source to power logic circuitry can support satisfactory device performance for a variety of applications, while enhancing long-term stability of the circuitry. For example, when organic thin film transistor (OTFT)-based logic circuitry is powered by an ac power source, the logic circuitry exhibits stable performance characteristics over an extended period of operation. Enhanced stability may permit the use of OTFT logic circuitry to form a variety of circuit devices, including inverters, oscillators, logic gates, registers and the like. Such circuit devices may find application in a variety of applications, including integrated circuits, printed circuit boards, flat panel displays, smart cards, cell phones, and RFID tags. In some applications, the ac-powered logic circuitry may eliminate the need for ac-dc rectification components, thereby reducing the manufacturing time, expense, cost, complexity, and size of the component carrying the circuitry.