Charge pump control circuit

Abstract

The invention discloses a charge pump control circuit, which comprises a power detection circuit, a logic control circuit, a charge pump module, an oscillator, comparators, an operational amplifier, divider resistors R1 and R2, and a load capacitor CL, wherein the power detection circuit divides a power voltage into a voltage of less than 2.7 V, a voltage of 2.7 to 4.6 V and a voltage of more than 4.6 V, detects that the power voltage is in a certain range, and then inputs information to the logic control module in a digital signal form such that a gain mode of a charge pump is determined, and maximum power is obtained; and the comparators are COMP 1 and COMP2, negative input ends of the two comparators are connected with an output end of the operational amplifier, and two saw-tooth waves with different phases are respectively input into positive input ends of the two comparators. Compared with the conventional hopping cycle control mode, the charge pump control circuit has the advantage that: a ripple wave of an output voltage is greatly reduced. Compared with the conventional linear regulation mode, the charge pump control circuit has the advantages that: the area of a power tube is greatly decreased, so that the ripple wave of the output voltage is greatly improved on the basis of no increase of the cost of a chip.

Description

technical field [0001] The invention belongs to the technical field of analog integrated power supply chips, and in particular relates to a switched capacitor charge pump loop control circuit. Background technique [0002] With the rapid development of electronic portable products, the demand for power management chips has also increased sharply. Charge pumps use capacitors to transfer charge and energy, so they have the advantages of no inductive components, no electromagnetic interference, low cost, and high efficiency. Therefore, this type of power management chip is very popular in handheld electronic devices. [0003] At present, there are two main control modes of the charge pump, one is the skip cycle control mode; the other is the linear regulation control mode. In skip cycle mode, after selecting the appropriate gain mode according to the power supply voltage value, when the output voltage is greater than the predetermined value V o When the output voltage is divi...

AI Technical Summary

Problems solved by technology

However, due to the addition of the PMOS transistor MP in the linear regulation mode, in the case of outputting a maximum constant current of 400mA, the width-to-length ratio of the PMOS transistor reaches 10. 6 : 1 magnitude, and due to the on-resistance of MP, in order to obtain the same driving capability in skip cycle mode, it is necessary to reduce the on-resistance of other switching tubes, so it is inevitable to increase the width-to-length ratio of other switching tubes, Therefore, the layout area of ​​the linear regulation mode needs to be greatly increased

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