Front end for RF transmitting-receiving systems with implicit directional control and time-multiplexing method in submicron technology
View Patent ↗A new design configuration of an RF-transceiver front end is proposed. The Power Amplifier (PA) output stage of the transceiver comprises a cascode circuitry of N-type transistors with open-drain-configuration. The cascode-transistor is acting as a common-gate-transistor, whose gate is controlled to block the transmitting-(TX) path. The Low Noise Amplifier (LNA) input stage uses a common-gate configuration of a p-channel MOS-transistor that is controlled by the voltage at the bulk terminal. Lifting the bulk potential of this PMOS-transistor above its source potential disables the receiving-(RX)-path. This design allows low cost implementation for TDMA-RF-transceivers especially for Bluetooth-Solutions. The number of external components is reduced. No additional TX/RX switch is required. The same port and the same matching elements for the antenna's bandwidth adaptation are used for both the TX-path and the RX-path.
1. RF-transceiver front-end comprising:
a. a Power Amplifier (PA) output stage comprising a transistor cascade circuitry that acts in open-drain-configuration during broadcast (TX) period as a common-gate-transistor with constant biasing, and acts in the open-drain-configuration during the receive (RX) period to change potential of the gate of the transistor cascade circuitry such that the path utilized during the TX period from the antenna is isolated; and
b. a Low Noise Amplifier (LNA) input stage comprising:
a p-channel metal oxide semiconductor field effect transistor which transistor is in common-gate configuration and its bulk changes the bulk's voltage-potential from a level equal to the source voltage potential to a level above the source voltage potential of this PMOSFET,
wherein the RF-transceiver front-end provides direction control for Time Division Multiple Access Communication (TDMA) for a quadband ISM transceiver implemented on a single integrated circuit.
2. The RF-transceiver front-end of claim 1 , wherein drain of field effect transistor of the LNA input stage is electrically connected to a resistive load and to input of a second amplifier stage and gate of the field effect transistor is set to a bias voltage level to enable receiving or this gate is forced to positive supply voltage to pinch off antenna voltage.
3. The RF-transceiver front-end of claim 2 , wherein a main transistor of the transistor cascade circuitry of the PA output stage is an n-channel metal oxide semiconductor field effect transistor and wherein base or respectively gate of the transistor is electrically connected to output of a preamplifier.
4. The RF-transceiver front-end of claim 1 , wherein main transistor of the transistor cascade circuitry of the PA output stage is an n-channel metal oxide semiconductor field effect transistor and wherein base respectively gate of the transistor is electrically connected to output of a preamplifier.
5. The RF-transceiver front-end of claim 1 , wherein the transistor cascade circuitry applies a voltage potential that is higher than drain voltage potential of this transistor.
6. The RF-transceiver front-end of claim 1 , wherein a charge pump generates a voltage-level whose height is above maximum positive supply voltage.
7. The RF-transceiver front-end of claim 1 , wherein when an open drain terminal of the PA output stage and an open source terminal of the LNA input stage are not electrically connected to same port of the single integrated circuit, then these terminals electrically contact same antenna at least approximately at same point.
8. The RF-transceiver front-end of claim 1 , wherein an open drain terminal of the PA output stage and an open source terminal of the LNA input stage are electrically connected to additional matching components especially to a external tuning coil.
9. The RF-transceiver front-end of claim 1 , wherein all stages of the PA and the LNA are symmetrically differential.
10. The RF-transceiver front-end of claim 9 , wherein differential outputs of the PA output stage and differential inputs of the LNA input stage use same differential port terminals and/or contact electrically at suitable connections of same differentially driven loop antenna that is unique transmit- and receive-antenna of the transceiver front-end.
11. The RF-transceiver front-end of claim 10 , wherein the differential outputs of the PA output stage and the differential inputs of the LNA input stage are electrically connected to external tuning coils.