Abstract: Techniques are described for adjusting an amount of current flowing through a first and second transistor of a voltage regulator connected to an output of a voltage regulator to maintain an output of the voltage regulator at a constant output voltage level. Also, a resistor connects a gate of the first transistor to a gate of a second transistor. The techniques may also charge or discharge a parasitic capacitance of the first transistor with a first current source connected to the gate of the first transistor and a second current source connected to the gate of the first transistor through the resistor.

Abstract: A light emitting element driver composed of two transistors, one ground resistor, one inductance and a single capacitor is arranged to drive an LED with a supplied voltage as low as about 0.92 V. The transistors include an NPN transistor and a PNP transistor, the base of the PNP transistor being connected to the ground resistor and the base of the NPN transistor being connected to the collector of the PNP transistor, with the capacitor being connected between the base of the PNP transistor and the node connecting the collector of the NPN transistor to the inductance and to the LED.

Abstract: A method and apparatus for implementing DC mode selection in a data access arrangement (DAA). The present invention overcomes the geographic constraints of the prior art by providing a plurality of selectable DC modes. Each of the selectable DC modes may be designed to meet the DC mask specifications of a desired country or region. The apparatus of the present invention may then be utilized in any of the desired countries or regions by selecting the appropriate DC mode. To accommodate several possible DC mask parameters, embodiments of the present invention include selection between a plurality of DC mode voltage levels, selection between current limiting and non-current limiting DC modes, and selection between a plurality of current limit values. Control elements, such as opto-couplers controlled by a microcontroller, are used to perform the selection by enabling and disabling circuit elements or connections. One embodiment provides for temperature compensation of DC current limiting.