Self-compensating current steering charge pump circuit

Abstract

The invention discloses a self-compensating current steering charge pump circuit. The self-compensating current steering charge pump circuit comprises a charging / discharging current source compensating circuit and a charge pump core circuit, the charging / discharging current source compensating circuit adopts a self-compensation technology, when the output voltage of the charge pump changes, the charging / discharging current self-compensation of the charge pump is realized, and the charging / discharging current matching characteristic is improved; a charge pump core circuit adopts four pairs of complementary switches to reduce clock feed-through and charge injection effects of a charge pump circuit, an amplifier A1 adopts unity gain connection to enable output voltage VC of the amplifier A1 to change along with change of output voltage Vout of a charge pump, and a circuit charge sharing effect is inhibited; the charge / discharge current source of the charge pump core circuit adopts a gainboosting technology, the output impedance of the charge / discharge current source of the charge pump is improved, the change of the charge / discharge current source caused by the change of the output voltage of the charge pump is inhibited, and the matching performance of the charge / discharge current source of the charge pump is improved, so that the self-compensating current steering charge pump circuit is realized.

Description

technical field [0001] The invention belongs to the technical field of microelectronics, and in particular relates to a self-compensating current steering charge pump circuit. Background technique [0002] With the development of communication and computer technology, the requirements for signal transmission and processing speed are getting higher and higher, so the clock signal required by the system puts forward higher requirements. Phase-locked loops are widely used in system clock signal generation circuits because of their high stability, no jitter accumulation, and low phase noise. As an important part of the phase-locked loop, the charge pump circuit directly affects the performance of the entire phase-locked loop system, and then affects the performance characteristics of the system. [0003] figure 1 It is a traditional charge pump circuit, Iup is a charging current source, PMOS tube M1 is a charging switch, NMOS tube M2 is a discharging switch, CL is a filter cap...

AI Technical Summary

Problems solved by technology

In any case, the traditional charge pump circuit has problems such as charge sharing, current mismatch, and feedthrough. For example, when the switch tube M1 and the switch tube M2 are both turned off, the output terminal Vout remains in a floating state. Due to the current source Iup and the current source Idn There are parasitic capacitances at both ends, so that the voltages of the source node of the switch tube M1 and the source node of the switch tube M2 are pulled to the power supply VDD and the ground respectively; when the switch tube M1 and the switch tube M2 are turned on, due to the voltage of the switch tube M1 The parasitic capacitance of the source node, the parasitic capacitance of the source node of the switch tube M2 has a charge sharing effect with the load capacitance CL, which causes ripples at the output of the charge pump, which directly affects the performance characteristics of the phase-locked loop

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