| 摘要 |
An unit charge pump is provided to allow the voltage values of the bootstrap node in the initial operation to have the same voltage level and to prevent the overvoltage in the bootstrap node when entering in the standby mode. The first type 2 phase cross coupled unit charge pump(400) comprises the free charge controllers (410, 420), the NMOS charge transfer switches(MN1, MN2), the cross coupled PMOS charge transfer switches(MP1, MP2), the bulk bias feed ports (430, 440), a bootstrap node overvoltage preventing part(450), a plurality of electric charge pumping capacitors(C0 ~ C3), and a plurality of inverters(I0~I3). The gates of the first PMOS charge transfer transistor and the second PMOS charge transfer transistor are cross-coupled. The first and second NMOS charge transfer switches switch the input voltage(VIN) to the first and second bootstrap node. The first and second PMOS charge transfer switches switch the voltage of the first and second bootstrap nodes to the output terminal(OUT). The free charge controllers apply the free charge control signal to the gates of first and second NMOS charge transfer transistor. |
