Fast startup charge pump

摘要

A charge pump is designed to be capable of quick start up. When the enable signal of the charge pump is arrived, the pump capacitor and the load capacitor of the charge pump can be charged in a short time, referred to as a pre-charging stage. During the normal working period, the pump capacitor and the output capacitor are controlled by the proper switch that is configured into the connection relationship that the charge pump can normally work in order to make the charge pump work normally. As a result of the pre-charge operation, embodiments disclosed herein can reduce the time of the output capacitor for reaching a steady state value.

主权项

1. A fast startup charge pump circuit, comprising:
a charge pump; and an output stage; wherein the load of the charge pump, during the period of pre-charging time, that is, during the short period of time when the charge pump starts-up, switch (Spre) and switch (Spreb) are set as: once the charge pump is negative charge pump, the switch (Spre) is ON (having low-impedance), the switch (Spreb) is OFF (having high-impedance); once the charge pump is positive charge pump, the switch (Spre) is OFF (having high-impedance), the switch (Spreb) is ON (having low-impedance); once the pre-charging is over, the switch (Sper) and the switch (Spreb) are in the position that opposite to the state in the period of pre-charging time.