Single supply RF switch driver
A single supply RF switch driver. The single supply RF switch driver includes an inverter, where a first resistor has been integrated within the inverter, and the resistor is connected to an RF switch. In one aspect, the integration of the first resistor within the inverter allows for the elimination of a negative power supply for the inverter, while maximizing the isolation achieved in the RF switch. In another aspect, the driver is a configured to have a second resistor integrated within the inverter. A third resistor is connected between the gate of the RF switch and the inverter. In an alternate aspect, the driver operates from a positive power supply and a negative power supply, thus increasing the isolation in the RF switch even further.
1. A radio frequency (RF) circuit comprising:
a first RF node;
a second RF node;
a control input;
a series switch coupled between the first RF node and the second RF node, the series switch comprising at least a first metal-oxide-semiconductor field effect transistor (MOSFET);
a shunt switch coupled between the first RF node and a ground node, the shunt switch comprising at least a second MOSFET and a gate resistor; and
a driver circuit coupled to the shunt switch;
wherein a turn on time of the shunt switch is different than a turn off time of the shunt switch.
2. The RF circuit of claim 1 , the driver circuit further comprising:
a supply voltage input,
a driver output,
a first driver MOSFET with its source coupled to the supply voltage input,
a second driver MOSFET with its source coupled to ground,
a first driver resistor coupled between a drain of the first driver MOSFET and the driver output, and
a second driver resistor coupled between a drain of the second driver MOSFET and the driver output
wherein a first resistance of the first driver resistor is different than a second resistance of the second driver resistor.
3. The RF circuit of claim 2 , wherein the first resistance of the first driver resistor is higher than the second resistance of the second driver resistor.
4. The RF circuit of claim 1 , wherein the shunt switch further comprises:
a plurality of MOSFETs and a plurality of gate resistors,
wherein each of the plurality of MOSFETs is coupled to a respective gate resistor of the plurality of gate resistors.
5. The RF circuit of claim 4 , the driver circuit further comprising:
a first supply voltage input,
a second supply voltage input,
a driver output,
a first driver MOSFET with its source coupled to the first supply voltage input,
a second driver MOSFET with its source coupled to the second supply voltage input,
a first driver resistor coupled between a drain of the first driver MOSFET and the driver output, and
a second driver resistor coupled between a drain of the second driver MOSFET and the driver output
wherein a first resistance of the first driver resistor is different than a second resistance of the second driver resistor.
6. The RF circuit of claim 5 , wherein the first resistance of the first driver resistor is higher than the second resistance of the second driver resistor.
7. The RF circuit of claim 5 , wherein the second supply voltage input is coupled to a negative voltage.