Charge-Discharge Oscillation Circuit for Continuous Temperature Compensation
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Solution Overview
Problem
Existing oscillation circuits in semiconductor devices suffer from temperature-dependent frequency changes, leading to increased noise and jitter due to discrete changes in capacitance or resistance elements, which are switched to compensate for temperature variations.
Innovation Solution
A charge-discharge type oscillation circuit with a control current generation unit that includes a reference voltage generation circuit, a temperature characteristic slope correction circuit, and a voltage-current conversion circuit, which continuously adjusts the oscillating frequency by correcting the temperature characteristic of the control current, eliminating the need to switch capacitance or resistance elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If capacitance or resistance elements are switched to compensate for temperature changes, then the oscillating frequency is temperature compensated, but noise and jitter increase due to discrete changes
Solution Approach 1:
The patent applies continuous adjustment of the control current through analog voltage adjustment means, replacing the discrete switching of capacitance or resistance elements. This continuous adjustment maintains smooth oscillation frequency changes across temperature variations, eliminating the noise and jitter caused by abrupt discrete switching while achieving effective temperature compensation.
Solution Approach 2:
The patent changes the control parameter from discrete capacitance/resistance values to continuous analog voltage, which then controls continuous current adjustment. This parameter transformation enables smooth frequency modulation without the harmful discrete transitions, resolving the contradiction between temperature compensation and noise reduction.
2Temperature
If multiple capacitance or resistance elements are switched for frequency adjustment, then temperature compensation is achieved, but device complexity increases
Solution Approach 1:
The patent extracts and eliminates the complex switching mechanism for multiple capacitance or resistance elements, replacing it with a simpler analog voltage adjustment system. This extraction removes unnecessary circuit complexity while retaining the essential temperature compensation function through continuous parameter control.
Solution Approach 2:
By changing from discrete element switching to continuous analog voltage control, the patent simplifies the circuit architecture. The single analog control voltage replaces multiple switched elements and their associated switching circuitry, reducing device complexity while maintaining temperature compensation capability.
3Speed
If discrete capacitance or resistance elements are used for frequency control, then the oscillation circuit operates, but the oscillating frequency changes in discrete values rather than continuous values
Solution Approach 1:
The patent implements continuous frequency adjustment by using analog voltage to control the current through the oscillation circuit. This continuous control mechanism eliminates the discrete steps inherent in switching between fixed capacitance or resistance values, providing smooth and continuous frequency variation across the entire operating range.
Solution Approach 2:
The patent transforms the control parameter from discrete digital values to continuous analog voltage, enabling continuous frequency adjustment. This parameter change allows the oscillation frequency to vary smoothly without discrete jumps, improving the stability and continuity of frequency composition while maintaining responsive frequency control.
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
This solution allows for continuous temperature compensation of the oscillating frequency, reducing noise and jitter while minimizing circuit size and manufacturing costs, and enabling accurate clock signal generation in microcomputers and electronic devices.
Implementation Method 1
a reference voltage generation circuit that generates a reference voltage having a first temperature characteristic
Implementation Method 2
a temperature characteristic slope correction circuit that corrects a slope of a temperature characteristic of the reference voltage in accordance with the first correction information and generates an output voltage having a second temperature characteristic
Implementation Method 3
a voltage-current conversion circuit that converts the output voltage of the temperature characteristic slope correction circuit into the control current, and that corrects the control current value in accordance with second correction information
Implementation Method 4
a charge-discharge type oscillation unit that performs an oscillation operation at an oscillating frequency that is associated with a control current value
Implementation Method 5
The temperature dependence of the oscillating frequency of the charge-discharge type oscillation unit is suppressed by a temperature characteristic of the control current
Data Source
AI summary
An oscillation circuit has a charge-discharge type oscillation unit that performs an oscillation operation at an oscillating frequency that is in accordance with a control current value, and a control current generation unit that generates the control current. The control current generation unit includes a reference voltage generation circuit that generates a reference voltage that has a first temperature characteristic, a temperature characteristic slope correction circuit that corrects a slope of a temperature characteristic of a reference voltage in accordance with first correction information and generates an output voltage that has a second temperature characteristic, and a voltage-current conversion circuit that converts the output voltage of the temperature characteristic slope correction circuit into the control voltage, and that corrects the control current value in accordance with second correction information.