A delayed power-on switch designed for HMC609 application circuits

The HMC609 is a representative of RF amplifiers that demand a certain power up sequence. It is critical that its bias gate voltage must come before the power supply voltage Vdd. In this paper, we propose a novel switching circuit that can delay the arrival of power supply voltage, in order to obey the power up sequence. The working principle of this time-delay switch is based on the transient response of first order RC circuit and the switching characteristic of P-channel MOSFET. A simulation result of this circuit structure is given to verify the function of the designed switch. This design has obvious advantages over other common used measures of power management, and can be applied to many other models of amplifiers.