HIGH SPEED AND LOW VOLTAGE CHARGE PUMP OF PHASE SYNCHRONOUS LOOP

摘要

PURPOSE: A high speed and low voltage charge pump of a phase synchronous loop is provided to make the output load of a charge pump high and to make the size of the output current changed automatically according to the loop filter voltage. CONSTITUTION: The high speed and low voltage charge pump(200) of the phase synchronous loop includes many transistors. A source of the charge transistor(M11) is connected to the power voltage(VCC). The gate and drain of a charge bias transistor(M12) are connected to the gate of the charge transistor(M11). The drain of a charge switching transistor(M7) is connected to the drain of the charge bias transistor(M12). The source of a P channel MOS transistor(M10) is connected to the drain of the charge transistor(M11) and the gate and drains are connected the output node(Icm). The gate and drains of an N channel MOS transistor diode(M9) is connected to the output node(Icm). The gate of a discharge switching transistor(M8) is connected to the discharge input signal(DP) and the drain is connected to the source of the N channel MOS transistor diode(M9) and the source of that is connected to the node a. The drain of a discharge bias transistor(M1) is connected to the node a and the source of that is connected to the bias(VSS).