Texas Instruments Incorporated Deutschland, Gmbh

Texas Instruments Corporation

Laszlo Goetz

Stefan Reithmaier

Kevin Scoones

Martin Rommel

The invention relates to a reference voltage source including a bipolar transistor having a base, a collector and an emitter electrode. The reference voltage source further comprises a Schottky diode (D) whose anode is connected to the base electrode of the bipolar transistor and whose cathode is connected to the collector electrode of the bipolar transistor. The currents flowing through the Schottky diode and bipolar transistor are each set so that a temperature-independent reference voltage (VREF) materializes at the collector electrode of the bipolar transistor.

Reference voltage source

A digital driver circuit with one or more CMOS inverters intended as input stages, whereby for the MOS FETs of the inverters the channel width/length (W/L) ratio increases from stage to stage. The digital driver circuit includes an intermediate stage with two further CMOS inverters, connected between a supply voltage Vcc and ground. The driver circuit also includes an output stage having two MOS FETs with the drain terminals of both the MOS FETs of the output stage connected both to each other and to the output of the circuit, the W/L ratio of both MOS FETs exceeding that of the MOS FETs of the intermediate stage. The switch-over of the two MOS FETs of the output stage, occurring with changes of the digital input signal at the input of the circuit, is offset in time with respect to each other, thereby reducing current peaks.

Digital driver circuit

For compensating the Early effect a band gap reference voltage source includes current mirror circuits (T.sub.4, Q.sub.3 and T.sub.1, Q.sub.1 as well as T.sub.2, Q.sub.2) to ensure that the currents necessary for achieving the temperature-compensated output voltage are generated. Using the current mirror circuits makes the reference voltage source independent of changes in the supply voltage (U.sub.cc) and enables it in particular to be employed at supply voltages as of low as 3 V.

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Freising, Germany

Laszlo Goetz