Switching circuit
A switching circuit that includes a first transfer path and a second transfer path that transfer a high frequency signal, a first transistor that electrically cuts off a common node between the first transfer path and the second transfer path and the first transfer path if the high frequency signal is transferred via the second transfer path, a second transistor that electrically cuts off the common node and the second transfer path if the high frequency signal is transferred via the first transfer path, a first control voltage input terminal that inputs a high-level control voltage if the high frequency signal is transferred via one of the first transfer path and the second transfer path, and a first voltage supply path that supplies a voltage according to the high-level control voltage to the common node.
1 . A switching circuit comprising:
a first transfer path and a second transfer path that transfer a high frequency signal;
a first transistor that electrically cuts off a common node between the first transfer path and the second transfer path and the first transfer path if the high frequency signal is transferred via the second transfer path;
a second transistor that electrically cuts off the common node and the second transfer path if the high frequency signal is transferred via the first transfer path;
a first control voltage input terminal that inputs a high-level control voltage if the high frequency signal is transferred via one of the first transfer path and the second transfer path; and
a first voltage supply path that supplies a voltage according to the high-level control voltage to the common node.
2 . The switching circuit according to claim 1 , wherein
the first voltage supply path includes a diode, and
an anode of the diode is connected to the first control voltage input terminal and a cathode of the diode is connected to the common node.
3 . The switching circuit according to claim 1 , further comprising:
a third transfer path that is connected to the common node and transfers a high frequency signal, the high frequency signal having lower power than the high frequency signal transferred via one of the first transfer path and the second transfer path;
a third transistor that electrically cuts off the common node and the third transfer path if the high frequency signal is transferred via one of the first transfer path and the second transfer path; and
a fourth transistor, wherein
a control terminal of the fourth transistor is connected to the first control voltage input terminal and electrically connects the third transfer path and a ground terminal if the high-level control voltage is input.
4 . The switching circuit according to claim 3 , further comprising:
a first resistance element that is connected between the control terminal of the fourth transistor and the first control voltage input terminal; and
a second resistance element that is connected between the cathode of the diode and the common node,
wherein a resistance of the second resistance element is smaller than a resistance of the first resistance element.
5 . The switching circuit according to claim 1 , wherein
an antenna is connected to the common node, and
one terminal of the first transistor and the second transistor is connected to the common node, and another terminal of the first transistor and the second transistor is connected to a transmit circuit that outputs the high frequency signal for transmission, and
one terminal of the third transistor is connected to the common node and another terminal is connected to a receive circuit that inputs the high frequency signal for reception.