Abstract: The present invention relates to Current mirror for generating a constant mirror ratio, comprising an output transistor (Tout) having a base, an emitter and a collector, wherein a current flowing through the collector of said output transistor (Tout) constitutes an output current (Iout) of said current mirror and the collector of said output transistor (Tout) is connectable to an output circuit, a buffer transistor having a base, an emitter and a collector, wherein the emitter of the buffer transistor is connected to the base of the output transistor, a buffer current source for providing a fixed buffer current, wherein said buffer current source is connected to the collector of the buffer transistor, and a buffer base voltage control means having an input connected to the base of the output transistor and an output connected to the base of the buffer transistor, wherein the base voltage control means is adapted to controlling a voltage at the base of the buffer transistor in response to a current at the inpu

Abstract: Optical disk systems comprising photo detectors (1) with variable gain amplifiers (10) and slicers (11) are provided with generators (12) in feedback paths between slicer (11) and amplifier (10) for controlling said amplifier (10) non-linearly. As a result, time constants of the control loop of said amplifier (10) which depend upon the level of the input signals are now compensated and the timing behavior of the control loop of said amplifier (10) has got a more continuous character. Said generator (12) comprises a converter (13) and is of low complexity and easy to integrate on a photo detector integrated-circuit together with said amplifier (10) and slicer (11) followed by a differential time delay detector (6). Said generator (12) comprises a further converter (14) with a capacitor (15) forming an integrator for making the mean value of the output voltage signal of said slicer (11) equal to zero.

Abstract: The optical signal receiving unit (10), which receives and processes an optical signal, can be programmed by the optical signal. The optical signal is detected by an optical sensor (20) and processed by a signal processor (40). The signal processor (40) has an operating mode, which is set by a programmable control unit (30). The control unit (30) is programmable by a program signal derived from the optical signal. In one embodiment the optical signal receiving unit (10) can be switched between two operating modes by a program switch signal provided at a program switch terminal (53). The apparatus (100) for reproducing information from an optical data carrier (101) comprises an optical signal receiving unit (10) according to the invention.

Abstract: An LC oscillator (I) comprises a cross-coupled PMOS transistor pair (Ma, Mb) coupled to a pair of capacitors (Cva, Cvb) and a pair of inductances (La, Lb). To enhance the signal amplification of the oscillator, a pair of auxiliary transistor circuits (Qa, Qb; Na, Nb) is provided which are coupled between the drain and, preferably, the source of each PMOS transistor. The capacitors (Cva, Cvb) are preferably variable capacitors and the inductances (La, Lb) are preferably connected to ground to allow a enlarged tuning voltage range.

Abstract: A PLL circuit (1) comprising a series coupling of a charge pump (10), a loop filter (20) and a voltage-controlled oscillator (30) generating an output frequency (f), said voltage-controlled oscillator (30) comprising tunable devices (C1, C2, C1?, C2, C3) controlled by a first control signal (Vt1) generated by the loop filter (20), the PLL circuit (1) being characterized in that it further comprises a leakage compensation circuit (40) for generating a leakage compensation signal (IL) to modify a control of the voltage-controlled oscillator (30), the leakage compensation signal (IL) being indicative for a leakage current in the tunable devices of the voltage-controlled oscillator (30).

Abstract: An improved differential inverter comprising a differential inverter having a differential input for receiving a first input signal and a second input signal, said inverter further comprising a differential control input for receiving a first control signal and a second control signal. The improved differential inverter further comprises a differential output for transmitting a first output signal and a second output signal. The improved differential inverter further comprises a controlled bias generator that generates the second vector of input signals in response to a bias control signal. The control bias signal is generated at an output of a voltage divider coupled to the differential output of the differential inverter said bias control signal being indicative for a DC voltage of the of the differential output.