scholarly journals Microwatt Switched Capacitor Circuit Design

1982 ◽  
Vol 9 (4) ◽  
pp. 263-273 ◽  
Author(s):  
E. Vittoz
Keyword(s):  
Low Voltage ◽  
Settling Time ◽  
Switched Capacitor ◽  
Mos Transistors ◽  
Weak Inversion ◽  
Switched Capacitor Circuits ◽  
Low Voltage Operation ◽  
Biquadratic Filter ◽  
Cmos Implementation ◽  
Current Drain

The micropower CMOS implementation of the three basic components of switched capacitor circuits is discussed. Switches must be carefully designed to allow low voltage operation and compensation of clock feed-through by dummy transistors. Matched capacitors can be implemented in single polysilicon technologies primarily designed for digital micropower circuits. Excellent micropower amplifiers are realized by using simple one-stage circuits which take advantage of the special behaviour of MOS transistors in weak inversion. Noise is shown to be independent of current level which only influences the settling time. Various ways of improving the settling time while keeping a very low current drain are described. A method of calculating the noise of a biquadratic filter is followed by examples of a filter and of other switched capacitor circuits.

scholarly journals Starter for Voltage Boost Converter to Harvest Thermoelectric Energy for Body-Worn Sensors

Energies ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 4092
Author(s):  
Grzegorz Blakiewicz ◽  
Jacek Jakusz ◽  
Waldemar Jendernalik
Keyword(s):  
Threshold Voltage ◽  
Low Voltage ◽  
Boost Converter ◽  
Mos Transistors ◽  
Weak Inversion ◽  
Thermoelectric Energy ◽  
On Chip ◽  
Voltage Swing ◽  
High Output Voltage ◽  
High Output

This paper examines the suitability of selected configurations of ultra-low voltage (ULV) oscillators as starters for a voltage boost converter to harvest energy from a thermoelectric generator (TEG). Important properties of particularly promising configurations, suitable for on-chip implementation are compared. On this basis, an improved oscillator with a low startup voltage and a high output voltage swing is proposed. The applicability of n-channel native MOS transistors with negative or near-zero threshold voltage in ULV oscillators is analyzed. The results demonstrate that a near-zero threshold voltage transistor operating in the weak inversion region is most advantageous for the considered application. The obtained results were used as a reference for design of a boost converter starter intended for integration in 180-nm CMOS X-FAB technology. In the selected technology, the most suitable transistor available with a negative threshold voltage was used. Despite using a transistor with a negative threshold voltage, a low startup voltage of 29 mV, a power consumption of 70 µW, and power conversion efficiency of about 1.5% were achieved. A great advantage of the proposed starter is that it eliminates a multistage charge pump necessary to obtain a voltage of sufficient value to supply the boost converter control circuit.

scholarly journals Multiple output CMOS current amplifier

2016 ◽  
Vol 64 (2) ◽  
pp. 301-306 ◽  
Author(s):  
B. Pankiewicz
Keyword(s):  
Low Voltage ◽  
Current Mirror ◽  
Mos Transistors ◽  
Output Current ◽  
Current Amplifier ◽  
Low Voltage Operation ◽  
Current Consumption ◽  
Current Follower ◽  
Differential Pair ◽  
A Current

Abstract In this paper the multiple output current amplifier basic cell is proposed. The triple output current mirror and current follower circuit are described in detail. The cell consists of a split nMOS differential pair and accompanying biasing current sources. It is suitable for low voltage operation and exhibits highly linear DC response. Through cell devices scaling, not only unity, but also any current gains are achievable. As examples, a current amplifier and bandpass biquad section designed in CMOS TSMC 90nm technology are presented. The current amplifier is powered from a 1.2V supply. MOS transistors scaling was chosen to obtain output gains equal to -2, 1 and 2. Simulated real gains are -1.941, 0.966 and 1.932 respectively. The 3dB passband obtained is above 20MHz, while current consumption is independent of input and output currents and is only 7.77μA. The bandpass biquad section utilises the previously presented amplifier, two capacitors and one resistor, and has a Q factor equal to 4 and pole frequency equal to 100 kHz.

Sign in / Sign up

Export Citation Format

Share Document