Capacitive charging current control circuit

Abstract

The invention provides a capacitive charging current control circuit. The circuit comprises a circuit switch, a filter capacitor and a control circuit. One end of the circuit switch is connected with the ground, a positive plate of the filter capacitor is connected with a power supply, and a negative plate of the filter capacitor is connected with the other end of the circuit switch. The control circuit is connected with a control end of the circuit switch and sends control signals to control on resistance of the circuit switch. The circuit switch controlled by gate voltage is added between the filter capacitor and ground connection, thereby achieving the aim of controlling charging current of the filter capacitor, adding no more power consumption after a chip is started normally, and being not capable of influencing working performance of the filter capacitor.

Description

technical field [0001] The invention relates to the field of chip design, in particular to a circuit for controlling the charging current of a filter capacitor. Background technique [0002] With the rapid development of digital equipment, the volume of digital equipment is getting smaller and smaller, and the functions are more and more. Correspondingly, there are stricter requirements on the power consumption and power-on current of the core component chips of these digital devices. In the prior art, in order to make the chip work more stably, it is often necessary to connect external filter capacitors to power pins and other parts outside the chip. However, in order to achieve a better filtering effect, filter capacitors with larger capacitance are often used. In specific use, it is found that the transient charging current of a larger filter capacitor is generally larger. For some chips that include a short-circuit protection mechanism for the power supply, the use...

AI Technical Summary

Problems solved by technology

Although such a technical solution can achieve a certain effect, it has two disadvantages: first, the larger the filter capacitor 102, the larger the required current-limiting resistor 106, if the current-limiting resistor 106 is too large, the chip 104 Actual power supply voltage VCC1=VCC-I 0 * R1 becomes smaller, which will cause adverse effects on the normal operation of the chip 104; secondly, after the chip 104 is normally powered on and started, the current limiting resistor 106 will bring additional bad losses, and the more the current limiting resistor 106 The greater the loss

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