November 27, 2002; All rights reserved Page 6 of 15 FIGURE 5. A resistor 34, of value R, is connected between the bases of the transistors 31 and 32. Most of these applications strongly rely on the accuracy of a current ratio m established with a set of 1+m PTAT current sources. Among the three techniques, the VTH-based current references are implemented using a tracking self-biasing topology … la or on the current source with improved performance depicted in Fig. 2. The emitter of the NPN transistor 31 is sized to be n times larger than the emitter of the NPN transistor 32.
The new topology generates the PTAT current from the ratio between the drain currents of two transistors in subthreshold operation. II.A. Figure 5: Current summing BGR [8] The circuit that sums the two currents is found in Figure 5. PTAT current source This circuit is shown in figure (1). The first generates the PTAT current; the second mirrors the current to another transistor, which generates the other component. Department of Computer Science & Engineering The Pennsylvania State University.
lb. Current Source & Bias Circuits CSE 577 Spring 2011 Insoo Kim, Kyusun Choi Mixed Signal CHIP Design Lab. Linearity is analyzed and a compensation strategy to improve it is developed. The last subcircuit This current is generally called proportional to absolute tem-perature, PTAT. It is composed of three subcircuits. They are theVTH-based current reference, the summing current reference using a proportional-toabsolute-temperature (PTAT) current and a complementaryto-absolute-temperature current, and the voltage-to-current (VI) convertor using a compensation voltage across a resistor. It can be shown that [2] the output current I2 has the following relation with temperature: (1) and therefore: (2) and C is clearly a positive constant.
The architecture for generating a nano-ampere proportional to absolute temperature (PTAT) current source is proposed. However, a PTAT CMOS current source has a temperature-dependent bias point, … A bandgap voltage reference is a temperature independent voltage reference circuit widely used in integrated circuits.It produces a fixed (constant) voltage regardless of power supply variations, temperature changes and circuit loading from a device. PTAT current Reference Figure (1). The PTAT current source 30 has two bipolar NPN transistors 31 and 32 having emitters connected to a ground rail 33. Abstract: A low-voltage, ultra-low-power sub-threshold proportional to absolute temperature (PTAT) current source is proposed. The current source of claim 12, wherein the last-recited current source constitutes a PTAT current source, said operational amplifier being adapted to be powered by an external current source, the external current source being adapted to supply current to said operational amplifier developed at least in part from the current supplied by said PTAT current source. Existing PTAT current sources are either based on the well-known circuit shown in Fig.
A PTAT current source 30, in accordance with the invention, is shown in FIG. Handout #20: EE214 Fall 2002 Voltage References and Biasing ©1993 Thomas H. Lee; rev. Abstract: Proportional to Absolute Temperature (PTAT) CMOS current sources are widely used in temperature sensors, bandgap references, and other temperature-compensating circuits. It commonly has an output voltage around 1.25 V (close to the theoretical 1.22 eV (0.195 aJ) band gap of silicon at 0 K). An Ultra-Low Power CMOS PTAT Current Source Carlos Christoffersen Department of Electrical Engineering Lakehead University Thunder Bay, ON P7B 5E1, Canada Email: c.christoffersen@ieee.org Greg Toombs Department of Electrical and Computer Engineering University of Windsor Windsor, ON N9B 3P4, Canada Email: greg.toombs@ieee.org Ali Manzak Department of Electrical Engineering … An important PTAT current source is the Meijer all-NPN cross-quad circuit, where the PTAT output current does not present a strong dependence on the bias current and requires only four matched transistors to be realised, being adequate to be implemented with discrete circuits.
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