A charge pump circuit for generating positive and negative voltage sources

Abstract

The invention discloses a charge pump circuit for generating positive and negative voltage sources. The charge pump circuit comprises a driving signal generation module and a charge pump, wherein the driving signal generation module consists of a three-phase frequency divider and three gate drivers; an external initial clock signal with a period of T0 is converted into six driving signals with periods of 3T0; and the six driving signals act on the grid electrodes of six MOS tubes in the charge pump respectively for driving the MOS tubes to enable the charge pump to output a positive voltage and a negative voltage with equivalent voltage values and opposite polarities to be used as the positive voltage source and the negative voltage source. The charge pump circuit for generating the positive and negative voltage sources provided by the invention can generate the positive voltage source and the negative voltage source with equivalent voltage values and opposite polarities; when the positive voltage source and the negative voltage source are applied to an earphone power amplifier, an output-free blocking capacitor function of the earphone power amplifier can be realized so as to lower POP sound in power on / power off of the earphone; and in addition, the charge pump circuit is relatively simple in structure, relatively less in used components and parts, and capable of saving cost of peripheral devices and reducing the area of a used PCB.

Description

technical field [0001] The invention relates to a positive and negative voltage source generating circuit, in particular to a charge pump circuit for generating positive and negative voltage sources. Background technique [0002] In traditional headphone amplifiers, because the static operating point of the output terminal is at half of the power supply voltage, in order to reduce power consumption and protect the headphones, a large DC blocking capacitor needs to be added to the output terminal for DC voltage isolation. Since the audio source signal must be output at a DC level (such as 1 / 2VDD), when powered on / off, the headphone amplifier will charge / discharge the DC blocking capacitor, such a DC jump from 0 level to 1 / 2VDD After passing through the DC blocking capacitor, POP sound will inevitably be generated on the earphone. [0003] In order to eliminate the POP sound when the earphone is powered on / off, it is usually necessary to eliminate the DC blocking capacitor ar...

AI Technical Summary

Problems solved by technology

However, this technical solution requires the application of a dual charge pump structure, four capacitors are required on the periphery, the logic circuit is more complicated, and the number of power transistors in the charge pump is also large.

There is no advantage in the cost of application and the volume of finished products

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