A high-speed 8/9 prescaler circuit, its control method and its phase-locked loop

Abstract

The invention discloses a high-speed 8 / 9 dual-mode prescaler, comprising 10 TSPC latches L1‑L10, 1 NAND gate (G2), 1 NOR gate (G3), a first NOT gate (G1) and the second NOT gate (G4); it is characterized in that: TSPC latches L1, L3, L5, L7 and L9 are first type latches, TSPC latches L2, L4, L6, L8 and L10 for the second type of latch. The high-speed 8 / 9 dual-mode prescaler proposed by the invention has high operating frequency and wide frequency band coverage.

Description

technical field [0001] The present invention relates to the field of high-speed analog circuits and radio frequency integrated circuits, in particular, to a dual-mode prescaler circuit, and more specifically, to a high-speed 8 / 9 prescaler circuit and its control method and including the Phase-locked loop for prescaler. Background technique [0002] In the phase-locked loop, the prescaler is often used as a part of the frequency divider to figure 1 The pulse-swallowing programmable frequency divider that is common in China is an example. The dual-mode 8 / 9 prescaler is used to divide the high-frequency signal output by the oscillator in the phase-locked loop to a lower frequency, and then input it to other programmable frequency dividers. In the frequency function module, the frequency divider can realize the frequency division ratio: 8×M+A, where M is the modulus value of the M counter, A is the modulus value of the A counter, and both M and A are integers. [0003] Commonl...

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Problems solved by technology

[0004] In frequency dividers based on TSPC logic, the available TSPC circuit structures are: TSPC flip-flop and TSPC latch. Reference 1 discloses a 2 / 3 dual-mode prescaler, and Reference 2 discloses 2 / 3, 4 / 5 prescaler, no matter it is reference 1 or reference 2, the prescaler disclosed by them adopts TSPC flip-flop, and some logic gate functions are also embedded in reference 2 In the TSPC flip-flop, the operating frequency of this dual-mode prescaler based on TSPC logic is greatly affected by the power supply voltage. In low power supply voltage, the TSPC flip-flop works slower than the TSPC latch

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