RC Oscillator Bulk-Voltage Compensation for Temperature Drift
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Solution Overview
Problem
Integrated circuits (ICs) with RC oscillators face inaccuracies due to temperature variations, particularly when semiconductor processes only provide resistors with a single polarity, limiting temperature compensation options.
Innovation Solution
An apparatus and method that utilize a voltage regulator with a current mirror, pass device, and diode circuit to generate temperature-compensated bulk voltages, which are used to power an RC oscillator, incorporating programmable resistors and capacitors to stabilize clock signals across varying temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If RC oscillators are used in integrated circuits, then clock signal generation is achieved, but temperature-induced frequency drift occurs reducing accuracy
Solution Approach 1:
The patent changes the electrical parameters (bulk voltages) of the oscillator circuit to compensate for temperature-induced frequency drift. By adjusting the bulk voltages of transistors in the RC oscillator, the oscillation frequency is tuned to maintain accuracy across different temperature conditions.
Solution Approach 2:
The patent replaces mechanical temperature compensation methods with electrical parameter adjustment. Instead of using physical mechanisms or external components, the solution uses electrical bulk voltage control to achieve temperature compensation, integrating the compensation function directly into the oscillator circuit.
2Measurement precision
If temperature compensation is implemented using traditional methods, then frequency accuracy is improved, but device complexity and external component requirements increase
Solution Approach 1:
The patent implements self-service by having the RC oscillator circuit compensate for its own temperature drift using internally generated bulk voltages. The oscillator uses its own power supply infrastructure to generate compensation signals, eliminating the need for external compensation circuits or components.
Solution Approach 2:
The patent merges the temperature compensation function with the existing power supply infrastructure of the integrated circuit. By using the bulk voltage generation capability already present in the power supply system, the compensation function is integrated without adding separate external components or complex additional circuitry.
3Reliability
If bulk voltages are used for temperature compensation, then frequency stability is improved, but power consumption increases
Solution Approach 1:
The patent achieves multi-functionality by using the bulk voltage generation circuit to serve both power supply and temperature compensation functions. The same bulk voltage infrastructure that powers the oscillator is also used to generate compensation signals, eliminating the need for separate compensation circuitry and reducing overall power consumption.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution effectively compensates for temperature-induced drift in RC oscillators, ensuring stable clock signal generation across a wide temperature range without requiring external bias currents or complex routing, thus enhancing the accuracy and reliability of ICs.
Implementation Method 1
a current mirror having at least one first node coupled to a supply voltage and an output to output a proportional-to-absolute current (PTAT) current
Implementation Method 2
a diode circuit comprising a first diode-connected transistor and a second diode-connected transistor, wherein the first diode-connected transistor is to receive the first bulk voltage and the second diode-connected transistor is to receive the second bulk voltage
Data Source
AI summary
In one aspect, an apparatus includes an oscillator to generate a clock signal, where the oscillator includes: at least one resistor; at least one capacitor; and a circuit coupled to the at least one resistor and the at least one capacitor, the circuit to generate the clock signal. The apparatus further includes a voltage regulator coupled to the oscillator to provide a regulated voltage to the oscillator, and a bulk voltage generator coupled to the voltage regulator. The bulk voltage generator may provide first and second bulk voltages to the voltage regulator to provide temperature compensation to the oscillator.