Flip-Flop Pulse Generator Layout for Faster Latch Switching
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Solution Overview
Problem
Existing semiconductor integrated circuit devices with high-speed flip-flop circuits face limitations due to parasitic capacitance and reduced operating speed caused by charge accumulation, especially in status holding circuits.
Innovation Solution
A semiconductor integrated circuit device with a pulse generator and latch circuit configuration that includes shared charge/discharge paths, switching units, and a second switching unit for discharging accumulated electric charges, allowing for faster operation by minimizing parasitic capacitance and reducing the time required for signal changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a status holding circuit is disposed in a latch circuit to hold the status of output signal, then the circuit can maintain output state, but the operating speed when the status of output signal is varied is reduced
Solution Approach 1:
The latch circuit is divided into two independent circuits: a first latch circuit for holding the output status and a second latch circuit for generating output signals. This segmentation allows each circuit to be optimized independently - the first latch maintains stability while the second enables fast status variation, thereby resolving the contradiction between reliability and speed.
2Speed
If high speed operating flip-flop circuits are used to increase performance, then the operating speed improves, but charge accumulation in parasitic capacitance limits further speed improvement
Solution Approach 1:
A pre-charge circuit is introduced that proactively discharges parasitic capacitance before the flip-flop operates. By performing this charge discharge action in advance, the circuit eliminates the time delay that would otherwise occur during normal operation, thereby maintaining high operating speed without being limited by charge accumulation effects.
3Speed
If the amount of electric charges accumulated in parasitic capacitance is reduced to speed up operation, then the operating speed increases, but the circuit may become more sensitive to noise and signal integrity issues
Solution Approach 1:
The pre-charge circuit dynamically adjusts the discharge timing and magnitude of parasitic capacitance based on the operating phase. By changing the parameters of charge discharge operations - discharging only when necessary and holding charge when needed - the circuit achieves high speed operation while maintaining sufficient signal levels for reliable operation, thus resolving the contradiction between speed and signal integrity.
Data Source
AI summary
The semiconductor integrated circuit device is a semiconductor integrated circuit device having a pulse generator and a latch circuit. The pulse generator has a first charge/discharge path and a second charge/discharge path and a charge unit for pre-charging first nodes. The first charge/discharge path and the second charge/discharge path include: two first switching units, connected to the first nodes, and configured to control, according to an input signal, conduction and non-conduction of the first charge/discharge path and the second charge/discharge path; and a second switching unit, disposed between a second node and a reference voltage node, and configured to be turned on in a period prior to capturing the input signal to allow an electric charge accumulated at the second node to be discharged to the reference voltage node, and at the same time, configured to be turned on in a period of capturing the input signal to allow the first node to discharge.