One example charge pump is provided. The example charge pump includes a degeneration circuit, a charging current source transistor, a switch circuit and a discharging current source transistor. The charging current source transistor provides a charging current. The degeneration circuit is coupled between a first terminal of the charging current source transistor and a power supply terminal. The degeneration circuit degrades a first voltage corresponding to the power supply terminal to a second voltage. The switch circuit is coupled between a second terminal of the charging current source transistor and a load. The switch circuit controls a charging current output to the load.