Charge pump parallel current sharing circuit based on duty ratio control

Abstract

The invention belongs to the technical field of integrated circuits, and particularly relates to a charge pump parallel current sharing circuit based on duty ratio control. According to the invention, the equivalent impedance of the charge pump is changed mainly by adjusting the duty ratio, and then the current sharing of the output current during the parallel operation of the charge pump is realized, specifically, the parallel current sharing is realized by enabling the charge pump power tube to work according to the output duty ratio through the duty ratio adjusting module connected with the charge pump. The scheme can be popularized to a charge pump framework with any conversion ratio. According to the scheme, the duty ratio is changed, and the frequency is not changed. Therefore, from the perspective of EMI, the energy spectrum is concentrated on the switching frequency and the harmonic frequency, and almost no energy exists in the range below the switching frequency, so that the design of system EMI is facilitated. The invention provides an analog implementation mode and a digital implementation mode.

Description

technical field [0001] The invention belongs to the technical field of integrated circuits, and in particular relates to a charge pump parallel current sharing circuit based on duty cycle control. Background technique [0002] The basic architecture of the charge pump is as figure 1 As shown, the four power transistors follow the complementary phase and conduct respectively. Under the ideal condition of no load, VX=2*VY, IX=IY / 2 (VX terminal current is half of VY terminal current). The most common application is to use VX as the input supply, resulting in approximately half the output voltage VY. Similarly, if VY is used as the input power supply, then the output voltage VX will be approximately doubled. If VX is the input terminal and VY is the output terminal, the voltage waveforms of CFLY in the two working states in the steady state are as follows figure 2 shown. exist phase, the capacitor voltage is RC charged between VX and VY; at phase, the capacitor vol...

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Problems solved by technology

[0015] 2) Current concentration and local hot spots will also accelerate the aging of devices

Generally, the aging speed of devices has an exponential relationship with temperature, and local hot spots are likely to cause accelerated scrapping of corresponding devices, thereby reducing the reliability of the entire system

[0016] 3) Each chip has a maximum current capability limit, and the system design needs to ensure that any chip does not exceed the current limit

Uneven current flow will inevitably lead to a drop in the total output current of the entire system

[0017] 4) At the beginning of the system design, it is not known which chip will concentrate the most current, which causes the system design to only allow each chip to be designed according to the maximum current. Such design redundancy causes system resources to waste of

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