Method for implementing charge pump keeping constant output current, and charge pump thereof

Abstract

The invention discloses a method for implementing a charge pump keeping constant output current, and the charge pump thereof. The method comprises the following steps of: comparing external input voltage of a charge pump main body circuit with reference voltage, and inputting a comparison result into a clock generating circuit to output corresponding clock oscillation frequency, so that the charge pump main body circuit outputs constant current. The output of the charge pump main body circuit is connected to an enable end of the charge pump main body circuit through a voltage feedback and comparison circuit. The external voltage is dynamically detected, and when the external voltage changes, corresponding clock oscillation frequency can be selected according to the external input voltage,so that the charge pump outputs constant current. Therefore, the output voltage ripple of the charge pump is reduced, and the output voltage stability is improved. The charge pump is simple in implementation mode and structure and low in cost.

Description

technical field [0001] The invention belongs to the field of electronic chip charge pumps, and relates to a method for realizing a charge pump that maintains a constant output current and a charge pump that uses the method to maintain a constant output current. Background technique [0002] The charge pump circuit is widely used in various electronic chips. Its principle is to use the charge accumulation effect on the capacitor to generate a voltage higher than the input voltage. Typically, a one-stage charge pump can provide a maximum voltage that is twice the input voltage, and a two-stage charge pump can provide a maximum voltage that is three times the input voltage. [0003] A charge pump system generally mainly includes three circuit modules: a clock oscillator, a feedback circuit, a comparator circuit, and a charge pump main circuit. The clock oscillator generates a clock signal to charge the main circuit of the charge pump; the output voltage is determined through t...

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Problems solved by technology

Poor output voltage stability will also lead to poor circuit performance of subsequent power modules, affecting the performance parameters of the entire chip, such as timing performance, speed performance parameters, etc.

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