Latch Isolation Circuit Using Passive Switch Network
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Solution Overview
Problem
Conventional latch circuits require pre-amplifiers for isolation, which increase space and power usage, and are costly.
Innovation Solution
A passive network of switches is used to sample and hold analog inputs before feeding them to a latch or comparator, eliminating the need for a pre-amplifier by employing a method where the latch input is selectively connected to a reference voltage and then to a node, allowing for the capture of an analog signal without a pre-amplifier.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a pre-amplifier is used to isolate the latch, then latch isolation is achieved, but area, power consumption, and circuit complexity increase
Solution Approach 1:
The patent extracts and removes the pre-amplifier component from the conventional latch circuit, replacing it with a passive switch network that performs isolation functions without requiring active amplification stages, thereby reducing circuit complexity while maintaining isolation performance
Solution Approach 2:
The patent introduces a passive switch network as an intermediary element between the latch input and the signal source, which mediates the isolation function by selectively connecting or disconnecting the latch input from the signal path based on clock phases, eliminating the need for a pre-amplifier
2Reliability
If a pre-amplifier is used to isolate the latch, then latch isolation is achieved, but area consumption increases
Solution Approach 1:
The pre-amplifier is extracted and removed from the circuit, replacing it with compact passive switches and capacitors that occupy significantly less silicon area while achieving the same isolation function
Solution Approach 2:
The patent uses simple passive components (switches and capacitors) that are cheaper and occupy less area compared to the complex pre-amplifier circuitry, accepting that these components need to be reconfigured each cycle but gaining significant area savings
3Reliability
If a pre-amplifier is used to isolate the latch, then latch isolation is achieved, but power consumption increases
Solution Approach 1:
The power-hungry pre-amplifier is extracted and replaced with passive switches that consume minimal power, eliminating the need for continuous amplification while maintaining isolation during critical latch operations
Solution Approach 2:
The patent employs periodic switching action controlled by non-overlapping clock phases, where switches are activated only during specific phases to perform sampling and isolation functions, reducing average power consumption compared to continuously operating pre-amplifiers
Data Source
AI summary
A system and method have been provided for passively isolating a latch circuit. The method provides a latch having a first input, an output, and a reset port. The latch first input is selectively connected to a first reference voltage. While the latch first input is connected to the first reference voltage, the latch is reset. Subsequent to disconnecting the latch first input from the first reference voltage, a first node is selectively connecting to the latch first input. In response to selectively connecting the first node, a first analog signal is supplied to the latch first input. Subsequent to resetting the latch, the first analog signal is captured and the latch output supplies a digital signal responsive to the captured first analog signal.