Switch circuit for controlling a connection between an antenna and an external circuit
AssigneeMurata Manufacturing Co., Ltd.
InventorsSatoshi Tanaka, Tadashi Matsuoka, Masanori Iijima, Yasushi Shigeno
Life of this patent
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Abstract
A switch circuit with a unit capable of improving a margin voltage without using a negative bias generation circuit is provided. A switch comprising an N-type MOSFET is used for a switch passing a signal to an antenna and a switch comprising a P-type MOSFET is used for a shunt switch grounding a signal. A common control signal is input to the gate terminal of the MOSFET constituting each switch. The inverted signal of this control signal is coupled to a ground terminal of the switch, and thus the potential of the gate terminal of each MOSFET can be set to the ground voltage.
Claims11
A switch circuit for determining whether an antenna is coupled to an external circuit, the switch circuit comprising a first switch passing an output of the external circuit to the antenna, a capacitor at an electrical connection point between the first switch and the external circuit, wherein
- a polarity of a control signal of the first switch is inverted by an inverter, and the inverted control signal is coupled to the connection point between the first switch and the capacitor,
- the switch circuit further comprises a first resistor included between the connection point and the inverter, a second resistor coupled in parallel to the first resistor, and a resistor opening/closing switch, and
- a value of the first resistor is made variable by opening/closing the resistor opening/closing switch.
A switch circuit for determining whether an antenna is coupled to an external circuit, the switch circuit comprising:
- a first switch passing an output of the external circuit to the antenna;
- and
- a second switch provided in the form of branching from a connection point between the first switch and the external circuit, the second switch being for grounding the external circuit when decoupled from the antenna, wherein
- the first switch and the second switch are controlled with a same control signal, and wherein
- the control signal is inverted so as to determine a potential of a ground terminal of the second switch,
- the switch circuit further comprising a capacitor at an electrical connection point among the first switch, the second switch, and the external circuit, wherein an inverted signal of the control signal is used for charging/discharging the capacitor.
A switch circuit for determining whether an antenna is coupled either to a transmission circuit or to a reception circuit, the switch circuit comprising:
- a transmission-side switch circuit for determining whether the transmission circuit is coupled to the antenna or the transmission circuit is grounded;
- and
- a reception-side switch circuit for determining whether the reception circuit is coupled to the antenna or the reception circuit is grounded, wherein
- the transmission-side switch circuit and the reception-side switch circuit are controlled with one control signal, and wherein the control signal is input to a ground terminal of either one of the transmission-side switch circuit or the reception-side switch circuit, and an inverted signal of the control signal is input to the other ground terminal,
- the switch circuit further comprising a third capacitor at an electrical connection point between the transmission-side switch circuit and the transmission circuit, wherein a signal according to the control signal is used in charging/discharging the third capacitor.
A switch circuit for determining whether an antenna is coupled either to a transmission circuit or to a reception circuit, the switch circuit comprising:
- a transmission-side switch circuit for determining whether the transmission circuit is coupled to the antenna or the transmission circuit is grounded;
- and
- a reception-side switch circuit for determining whether the reception circuit is coupled to the antenna or the reception circuit is grounded, wherein
- the transmission-side switch circuit and the reception-side switch circuit are controlled with one control signal, and wherein
- the control signal is input to a ground terminal of either one of the transmission-side switch circuit or the reception-side switch circuit, and an inverted signal of the control signal is input to the other ground terminal,
- the switch circuit further comprising a fourth capacitor at an electrical connection point between the reception-side switch circuit and the reception circuit, wherein
- a signal according to the control signal is used in charging/discharging the fourth capacitor.
Dependencies are inferred from the claim text.