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Ultra-low voltage two-stage annular voltage-controlled oscillator applied to chip circuit

A voltage-controlled oscillator, ultra-low voltage technology, applied in the direction of electric pulse generator circuit, logic circuit to generate pulse, electrical components, etc., can solve problems such as difficult to work normally, reduce power consumption, reduce power supply voltage, circuit The effect of simple structure

Pending Publication Date: 2018-02-27
APLUS SEMICON TECH CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

For ring oscillators, it is difficult to work well with a supply voltage of 0.5V due to the high threshold voltage of the transistors

Method used

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  • Ultra-low voltage two-stage annular voltage-controlled oscillator applied to chip circuit
  • Ultra-low voltage two-stage annular voltage-controlled oscillator applied to chip circuit
  • Ultra-low voltage two-stage annular voltage-controlled oscillator applied to chip circuit

Examples

Experimental program
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Effect test

Embodiment Construction

[0013] see figure 1 , is a schematic diagram of the variation of the threshold voltage of the MOS transistor with the substrate bias voltage. Substrate forward bias technology can effectively reduce the threshold voltage of MOS transistors.

[0014] Taking the 0.18um RF CMOS process as an example, the threshold voltage of NMOS and PMOS transistors is about + / -0.5V. When the power supply voltage is 0.5V, this threshold voltage will greatly limit the performance of the circuit. The threshold voltage can be lowered by forward biasing the substrate of the MOS transistor. Under the 0.18um RF CMOS process, the sensitive analog circuit is isolated from substrate noise by using a deep N well, so whether it is a substrate-connected NMOS transistor or a PMOS transistor, the threshold voltage can be lowered by forward biasing the substrate.

[0015] The threshold voltage (Vthp) of a PMOS transistor with a forward biased substrate can be expressed as:

[0016]

[0017] |V thp0 | is...

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Abstract

The invention relates to an ultra-low voltage two-stage annular voltage-controlled oscillator applied to a chip circuit. The oscillator is characterized by comprising two stages of delay units. The oscillator comprises the two delay units connected end to end, and working frequency is adjusted through adjusting delay time of the delay unit; each delay unit comprises PMOS transistors M1, M2, M3 andM4, NMOS transistors M5, M6, M7 and M8, and a load capacitor CL. According to the two-stage annular voltage-controlled oscillator provided by the invention, a substrate feedforward bias structure isused, the threshold voltage of the transistor is reduced, the supply voltage is reduced, the power consumption is deceased, and meanwhile, the relatively large tuning range is provided, so that the two-stage annular voltage-controlled oscillator is particularly applicable to the system of working at the low supply voltage.

Description

technical field [0001] The invention relates to the technical field of oscillators, in particular to an ultra-low voltage two-stage ring voltage-controlled oscillator used in chip circuits. Background technique [0002] Voltage controlled oscillator is an important building block of analog and digital circuits. There are many different implementations of voltage-controlled oscillators. Compared with traditional LC oscillators, ring oscillators occupy a smaller chip area and have a larger adjustment range. If a ring oscillator is constructed with two delay stages, it can operate at high frequencies and provide outputs in quadrature. [0003] In modern CMOS processes, the technical feature size and supply voltage need to be scaled down to maintain device stability. For ring oscillators, it is difficult to operate properly with a supply voltage of 0.5V due to the high threshold voltage of the transistors. Forward biasing the substrate connection of a MOS transistor is an eff...

Claims

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Application Information

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IPC IPC(8): H03K3/012H03K3/03
CPCH03K3/012H03K3/0315H03K5/00006H03K2005/00195H03K2005/00019H03K3/354
Inventor 蔡水河
Owner APLUS SEMICON TECH CO LTD