All-digital phase-locked loop built-in self-testing structure

Abstract

The invention discloses an all-digital phase-locked loop built-in self-testing structure. The time difference between a reference signal and a test signal is converted into a digital signal to be output. The all-digital phase-locked loop built-in self-testing structure comprises a signal processing unit, a first dual-path switch MUX1, a second dual-path switch MUX2, a phase-locked loop to be tested and a counter. The phase-locked loop to be tested is a charge pump phase-locked loop. The reference signal and the test signal are connected to the input end of the phase-locked loop to be tested through the first dual-path switch MUX1 and the second dual-path switch MUX2 respectively, the time difference delta T of two input signals is converted into frequency variation delta f through the phase-locked loop to be tested, then the number of pulses is counted through the counter, and the frequency variation delta f is converted into count value variation delta N. The all-digital phase-locked loop built-in self-testing structure has the advantages of being fully digital, high in precision and low in cost.

Description

technical field [0001] The invention relates to a novel all-digital phase-locked loop built-in self-test structure, which can simultaneously complete the fault test and jitter test of the phase-locked loop. Background technique [0002] The testing of mixed-signal circuits has a great impact on the time-to-market and production costs of electronic products, and it is a major problem that needs to be solved urgently for the continued development of mixed-signal integrated circuits. Phase-locked loops as mixed-signal modules are widely used in frequency synthesis, phase demodulation, clock distribution, and time recovery, and are an essential part of wireless communications, optical fiber links, and microcomputers. However, due to the closed-loop feedback and mixed-signal characteristics of the phase-locked loop, it becomes one of the most difficult circuits to test, and its testing has become an urgent problem to be solved internationally. Therefore, the research on the built...

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Problems solved by technology

PLL is the only mixed-signal circuit on most SoCs. Its test time and test cost are directly converted to the production cost of electron...

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