Apparatus for switching matching circuit in mobile communication terminal
View Patent ↗An apparatus for switching a matching circuit in a mobile communication terminal includes a PIN diode connected in parallel to an RF signal input and output line to be turned on and off to connect and disconnect an impedance matching-element to the RF signal input and output line in accordance with a frequency band switching-signal, and a bias circuit for generating a bias voltage applied to the PIN diode in accordance with the frequency band switching-signal, thereby shifting an amplitude of an RF signal to a positive side at an off-time of the PIN diode.
1. An apparatus for switching a matching circuit in a mobile communication terminal, comprising:
a PIN diode connected in parallel to an RF signal input and output line to be turned on and off to connect and disconnect an impedance matching-element to the RF signal input and output line in accordance with a frequency band switching-signal; and
a bias circuit for generating a bias voltage applied to the PIN diode in accordance with the frequency band switching-signal, thereby shifting an amplitude of an RF signal to a positive side at an off-time of the PIN diode.
2. The apparatus for switching a matching circuit in a mobile communication terminal according to claim 1 , wherein,
the bias circuit comprising:
an inverter for inverting the frequency band switching-signal; and
a limitation resistance for limiting an output current of the inverter to be applied to the PIN diode.
3. The apparatus for switching a matching circuit in a mobile communication terminal according to claim 2 , wherein,
the bias circuit comprising:
a first limitation resistance and a second limitation resistance for dividing a voltage to be applied to a cathode of the PIN diode.
4. An apparatus for switching a matching circuit in a mobile communication terminal, comprising:
an RF signal input and output line;
a matching circuit for switching a frequency band of an RF signal;
a switching circuit for connecting and disconnecting the matching circuit to the RF signal input and output line; and
a bias circuit for adding a predetermined DC voltage to the RF signal.
5. The apparatus for switching a matching circuit in a mobile communication terminal according to claim 4 , wherein,
the switching circuit is a PIN diode.
6. The apparatus for switching a matching circuit in a mobile communication terminal according to claim 4 , wherein,
the bias circuit comprising:
an inverter for inverting a frequency band switching-signal; and
a resistance for limiting an output current of the inverter to be applied to the switching circuit.
7. The apparatus for switching a matching circuit in a mobile communication terminal according to claim 5 , wherein,
the PIN diode is turned on and off by a frequency band switching-signal.
8. The apparatus for switching a matching circuit in a mobile communication terminal according to claim 6 , wherein,
the resistance comprising:
two resistances for dividing an output voltage of the inverter to be applied to the switching circuit.