Charge pump circuit with low current change and mismatch in wide dynamic range

Abstract

The invention discloses a charge pump circuit with low current change and mismatch in a wide dynamic range. The charge pump circuit is composed of a reference current source module, a low-dropout current mirror module, a charging and discharging matching module and a switch control module. The reference current source module adopts a self-starting cascode reference current source structure irrelevant to power supply voltage and generates reference current which is not influenced by fluctuation of the power supply voltage. The low-dropout current mirror module comprises two reference branches, reference current can be accurately copied in a wide output voltage range, the flatness of the current is kept, and the change rate of matched current is reduced. The charging and discharging matching module adopts a source electrode switch type charge pump with operational amplifier negative feedback, so that accurate matching of charging and discharging current can be realized, and the mismatching rate of the current is reduced. And the switch control module is controlled by the output voltage of the charge pump and feeds back to control the work of the low-dropout current mirror module. According to the invention, when the TSMC 0.18 [mu] m process is adopted and the power supply voltage is 1.8 V, the output voltage range of the charge pump is 0.01-1.79 V, and the current mismatch rate is less than 0.15%.

Description

technical field [0001] The invention relates to the technical field of integrated circuits, in particular to a charge pump circuit with low current variation and mismatch in a wide dynamic range. Background technique [0002] In recent years, with the development of integrated circuit technology, Phase-Locked Loop (PLL) has been widely used in various communication scenarios, such as: FM demodulator, signal reconstruction, clock signal recovery and frequency synthesis, etc. . A phase-locked loop can essentially be viewed as a system with a negative feedback loop that can automatically adjust the frequency and phase of the input signal. For a given input reference signal, the phase-locked loop can capture its frequency and phase through the loop, and can also achieve signal frequency multiplication and synthesis. A charge pump (Charge Pump, CP) is a key component of a phase-locked loop, and is often used together with a phase frequency detector (Phase Frequency Detector, PF...

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Problems solved by technology

[0004] In the prior art, there are two main methods for reducing the non-ideal characteristics of the charge pump: one is to increase the output impedance of the current mirror, which can reduce the current mismatch rate of the charge pump, but it is also easy to reduce the output of the charge pump The voltage margin reduces the output voltage range of the charge pump; the second is to design a dynamic current compensation circuit. This method can match the charging and discharging current in a wide voltage output range, but because the current change is nonlinear, the compensation The circuit has the problems of difficult design and complex design structure, and the situation of current mismatch and matching current change may be worsened under different process corners

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