Current Sensing Amplifier Offset Cancellation via Capacitive Coupling
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Solution Overview
Problem
In the field of non-volatile memory, the increasing density of memory units due to semiconductor manufacturing advancements leads to logic state errors during data reading due to threshold voltage offset, resulting in decreased data reading speed, as existing solutions like high-speed comparators and charge-share limited swing drivers require charging and discharging of capacitors, slowing down the logic data determination process.
Innovation Solution
A current sensing amplifier comprising a power input terminal, first and second current paths, switches, capacitors, and a latch circuit, where currents are injected to generate a potential difference between nodes, allowing capacitors to charge directly and amplify the difference independently of threshold voltage, thereby speeding up data logic state reading by coupling gate voltages through capacitors and using a latch circuit to raise one node to input voltage and drop the other to zero.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a high speed comparator with offset cancellation is used, then the threshold voltage offset effect is canceled, but the logic data determination speed is decreased due to the charging and discharging time of capacitors
Solution Approach 1:
The patent applies preliminary action by performing offset cancellation before the main sensing operation. The capacitor is charged during a preparation phase with known currents, establishing the offset compensation voltage beforehand. This allows the main sensing operation to proceed without waiting for capacitor charging/discharging during the actual data reading, thus maintaining high speed while achieving accurate offset cancellation.
Solution Approach 2:
The patent ensures continuity of useful action by making the capacitor charge path independent of the sensing current path. The capacitor charges continuously during the sensing operation itself, rather than requiring separate charging and discharging phases. This overlapping of operations eliminates idle time and maintains continuous productive action throughout the sensing process.
2Measurement precision
If a sensing amplifier with offset cancellation using capacitor charge storage is used, then the threshold voltage offset is corrected, but the data reading speed is decreased due to the charging and discharging state of the capacitor
Solution Approach 1:
The patent performs the capacitor charging action during the sensing operation itself rather than before it. The capacitor is connected to the sensing current path during the actual data reading phase, allowing the charging process to occur concurrently with the useful sensing operation. This eliminates the need for separate pre-charging time and reduces overall measurement time.
Solution Approach 2:
The patent dynamically controls the capacitor connection timing through switch elements. The capacitor is connected to the sensing current path only during the sensing phase when needed, and disconnected during other phases. This dynamic switching allows the system to adapt the capacitor charging behavior to the operational requirements, minimizing time loss while maintaining offset cancellation accuracy.
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 enables faster and accurate data reading by eliminating the dependency on threshold voltage, allowing for independent charging of capacitors and amplification of sensing currents, thus improving data reading speed and reducing errors caused by threshold voltage offsets.
Implementation Method 1
The first capacitor is connected between the gate of the first transistor and the second node. The second capacitor is connected between the gate of the second transistor and first node.
Implementation Method 2
The latch circuit is connected between the first node and the second node. When the first switch, the second switch, the third switch and the fourth switch are switched off and the latch switch is switched on, the voltage of one of the first node and second node is raised up to the input voltage and the voltage of the other is dropped to zero potential by the latch circuit.
Data Source
AI summary
The present invention relates to a current sensing amplifier and a method thereof. The current sensing amplifier comprises a first current path, a second current path, a first capacitor, a second capacitor and a latch circuit. When a first current and a second current flow in the first current path and the second current path respectively, the first and second capacitor may be charged by the first current and the second current. The first capacitor and the second capacitor may couple the charged voltage to the transistors in the first current path and the second current path when the first and second current path are cut off so as to cancel the effect of offset voltage of the transistors generated during the manufacturing process.