Peak and Bottom Detection Circuit With Dead-Time-Free Sampling
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Solution Overview
Problem
Conventional peak hold circuits experience dead time due to the sampling period and settling time of Analog to Digital (A/D) converters, which prevents accurate detection of voltage peaks and bottoms.
Innovation Solution
A peak/bottom detection circuit utilizing multiple capacitors and switches, controlled by a controller to switch connection destinations, allowing continuous detection without dead time by maintaining capacitors in pre-charge, detection, and hold states, enabling successive output of peak or bottom values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a conventional peak hold circuit with a single capacitor and A/D converter is used, then the circuit structure is simple, but dead time occurs due to sampling period and settling time preventing continuous detection
Solution Approach 1:
The single capacitor is segmented into three capacitors (first, second, and third capacitors) that operate in different states (pre-charge, detection, and hold states). This segmentation allows the detection function to be divided among multiple capacitors, enabling continuous detection without dead time while one capacitor is being charged and another is being detected.
Solution Approach 2:
The first capacitor is pre-charged to a reference voltage before detection begins. This preliminary action ensures that when the detection phase starts, the capacitor is already in the correct state, eliminating the need for resetting during detection and thus reducing dead time. The pre-charge operation is performed in advance during the hold state of the previous cycle.
2Productivity
If the A/D converter sampling period and settling time are reduced to eliminate dead time, then detection continuity improves, but measurement precision deteriorates
Solution Approach 1:
The detection process is segmented into distinct phases (pre-charge, detection, hold) that are executed sequentially across three capacitors. This segmentation allows each phase to be optimized independently - the detection phase can be given sufficient time for accurate measurement while the pre-charge and hold phases occur in parallel with other capacitor operations, maintaining both precision and continuity.
Solution Approach 2:
The useful action of voltage detection is maintained continuously by having three capacitors in different operational states simultaneously. While one capacitor is being detected, another is being pre-charged and a third is being held, ensuring that detection never stops. This continuous operation eliminates dead time without compromising measurement precision since each detection phase completes fully before the next begins.
3Productivity
If multiple capacitors and switches are added to eliminate dead time, then detection continuity improves, but device complexity increases
Solution Approach 1:
The three capacitors and their associated switches serve multiple functions within the detection cycle. Each capacitor can be in a pre-charge state, detection state, or hold state, and they cycle through these states sequentially. The same basic circuit components (capacitor, switch, comparator) are reused three times in different operational states, achieving continuous detection without requiring three completely separate detection circuits, thus limiting the increase in complexity.
Solution Approach 2:
The controller periodically switches the capacitors through three distinct states (pre-charge, detection, hold) in a cyclic manner. This periodic action allows the system to maintain continuous detection capability while using a relatively simple repeating pattern of switch operations. The periodic nature of the state transitions simplifies the control logic compared to more complex continuous control schemes.
4Loss of time
If the capacitor switching frequency is increased to reduce dead time, then detection continuity improves, but power consumption increases
Solution Approach 1:
The detection function is segmented across three capacitors operating in different states, which allows the switching frequency to be effectively distributed. Instead of one capacitor switching rapidly, three capacitors switch at a lower individual frequency while collectively providing continuous detection. This segmentation reduces the power consumption associated with rapid switching while maintaining detection continuity.
Solution Approach 2:
The pre-charge operation is performed in advance during the hold state of the previous detection cycle, rather than immediately before each detection phase. This preliminary action allows the capacitor to be ready for detection without requiring high-frequency switching. The pre-charging occurs at a lower frequency tied to the overall detection cycle rather than requiring rapid repeated charging, thus reducing power consumption while eliminating dead time.
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 configuration reduces power consumption and noise, allows for continuous detection, and provides sufficient time for A/D conversion, effectively eliminating dead time and enabling successive output of detection results.
Implementation Method 1
a comparator configured to compare a voltage of one of the three or more capacitors with an input voltage
Implementation Method 2
a calculation amplifier configured to amplify a voltage of one of the three or more capacitors
Data Source
AI summary
A peak/bottom detection circuit is disclosed. A comparator compares a voltage of one of three or more capacitors with an input voltage. A calculation amplifier amplifies the voltage of one of the three or more capacitors. Each of three or more switches respectively corresponding to the three or more capacitors connects a corresponding capacitor among the three or more capacitors to one of the comparator, the calculation amplifier, and a source of the input voltage. A controller generates control signals for sequentially switching connection destinations of the three or more capacitors and to supply the control signals to the three or more switches, respectively, in which the connection destinations of three capacitors among the three or more capacitors are different from each other.