Switch circuit and method of switching radio frequency signals
First Claim
1. An RF switch circuit for switching RF signals, comprising:
- (a) a first input port receiving a first RF input signal;
(b) a second input port receiving a second RF input signal;
(c) an RF common port;
(d) a first switch transistor grouping having a first node coupled to the first input port and a second node coupled to the RF common port, wherein the first switch transistor grouping is controlled by a switch control signal (SW);
(e) a second switch transistor grouping having a first node coupled to the second input port and a second node coupled to the RF common port, wherein the second switch transistor grouping is controlled by an inverse (SW_) of the switch control signal (SW);
(f) a first shunt transistor grouping having a first node coupled to the second input port and a second node coupled to ground, wherein the first shunt transistor grouping is controlled by the switch control signal (SW); and
(g) a second shunt transistor grouping having a first node coupled to the first input port and a second node coupled to ground, wherein the second shunt transistor grouping is controlled by the inverse (SW_) of the switch control signal (SW);
wherein, when SW is enabled, the first switch and shunt transistor groupings are enabled while the second switch and shunt transistor groupings are disabled, thereby passing the first RF input signal through to the RF common port and shunting the second RF input signal to ground; and
wherein when SW is disabled, the second switch and shunt transistor groupings are enabled while the first switch and shunt transistor groupings are disabled, thereby passing the second RF input signal through to the RF common port and shunting the first RF input signal to ground.
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Accused Products
Abstract
A novel RF switch circuit and method for switching RF signals is described. The RF switch circuit is fabricated in a silicon-on-insulator (SOI) technology. The RF switch includes pairs of switching and shunting transistor groupings used to alternatively couple RF input signals to a common RF node. The switching and shunting transistor grouping pairs are controlled by a switching control voltage (SW) and its inverse (SW_). The switching and shunting transistor groupings comprise one or more MOSFET transistors connected together in a “stacked” or serial configuration. The stacking of transistor grouping devices, and associated gate resistors, increase the breakdown voltage across the series connected switch transistors and operate to improve RF switch compression. A fully integrated RF switch is described including digital control logic and a negative voltage generator integrated together with the RF switch elements. In one embodiment, the fully integrated RF switch includes a built-in oscillator, a charge pump circuit, CMOS logic circuitry, level-shifting and voltage divider circuits, and an RF buffer circuit. Several embodiments of the charge pump, level shifting, voltage divider, and RF buffer circuits are described. The inventive RF switch provides improvements in insertion loss, switch isolation, and switch compression.
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Citations
42 Claims
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1. An RF switch circuit for switching RF signals, comprising:
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(a) a first input port receiving a first RF input signal;
(b) a second input port receiving a second RF input signal;
(c) an RF common port;
(d) a first switch transistor grouping having a first node coupled to the first input port and a second node coupled to the RF common port, wherein the first switch transistor grouping is controlled by a switch control signal (SW);
(e) a second switch transistor grouping having a first node coupled to the second input port and a second node coupled to the RF common port, wherein the second switch transistor grouping is controlled by an inverse (SW_) of the switch control signal (SW);
(f) a first shunt transistor grouping having a first node coupled to the second input port and a second node coupled to ground, wherein the first shunt transistor grouping is controlled by the switch control signal (SW); and
(g) a second shunt transistor grouping having a first node coupled to the first input port and a second node coupled to ground, wherein the second shunt transistor grouping is controlled by the inverse (SW_) of the switch control signal (SW);
wherein, when SW is enabled, the first switch and shunt transistor groupings are enabled while the second switch and shunt transistor groupings are disabled, thereby passing the first RF input signal through to the RF common port and shunting the second RF input signal to ground; and
wherein when SW is disabled, the second switch and shunt transistor groupings are enabled while the first switch and shunt transistor groupings are disabled, thereby passing the second RF input signal through to the RF common port and shunting the first RF input signal to ground. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40)
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41. An RF switch circuit switching RF signals, comprising:
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(a) a first input means for receiving a first RF input signal;
(b) a second input means for receiving a second RF input signal;
(c) an RF common port means;
(d) a first stacked transistor switching means having a first node coupled to the first input means and a second node coupled to the RF common port means, wherein the first stacked transistor switching means is controlled by a switch control signal (SW);
(e) a second stacked transistor switching means having a first node coupled to the second input means and a second node coupled to the RF common port means, wherein the second stacked transistor switching means is controlled by an inverse (SW_) of the switch control signal (SW);
(f) a first stacked transistor shunting means having a first node coupled to the second input means and a second node coupled to ground, wherein the first stacked transistor shunting means is controlled by the switch control signal (SW); and
(g) a second stacked transistor shunting means having a first node coupled to the first input means and a second node coupled to ground, wherein the second stacked transistor shunting means is controlled by the inverse (SW_) of the switch control signal (SW);
wherein, when SW is enabled, the first stacked transistor switching means and first stacked transistor shunting means are enabled while the second stacked transistor switching and the second stacked transistor shunting means are disabled, thereby passing the first RF input signal through to the RF common port means and shunting the second RF input signal to ground; and
wherein when SW is disabled, the second stacked transistor switching means and the second stacked transistor shunting means are enabled while the first stacked transistor switching and first stacked transistor shunting means are disabled, thereby passing the second RF input signal through to the RF common port means and shunting the first RF input signal to ground.
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42. A method of switching RF signals, comprising:
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(a) inputting a first RF input signal to a first switch transistor grouping and a first shunt transistor grouping, wherein the transistor groupings comprise a plurality of stacked transistors;
(b) inputting a second RF input signal to a second switch transistor grouping and a second shunt transistor grouping, wherein the transistor groupings comprise a plurality of stacked transistors;
(c) enabling the first switch transistor grouping while disabling the first shunt transistor grouping, and simultaneously disabling the second switch transistor grouping while enabling the second shunt transistor grouping, thereby passing the first RF input signal and shunting the second RF input signal; and
(d) enabling the second switch transistor grouping while disabling the second shunt transistor grouping, and simultaneously disabling the first switch transistor grouping while enabling the first shunt transistor grouping, thereby passing the second RF input signal and shunting the first RF input signal.
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Specification