What is claimed is:
1. An input switching circuit for a television tuner, comprising:
a first input terminal, to which a television signal is input;
a second input terminal, to which an FM broadcasting signal is input;
an output terminal;
a first switching circuit provided between said first input terminal and said output terminal, which, between said first input terminal and said output terminal, passes signal when receiving said television signal while blocking signal when receiving said FM broadcasting signal; and
a second switching circuit provided between said second input terminal and said output terminal, which, between said second input terminal and said output terminal, passes signal when receiving said FM broadcasting signal while blocking signal when receiving said television signal;
wherein said second switching circuit comprises:
first two diodes connected in series with each other between said second input terminal and said output terminal, which are turned off when receiving said television signal and turned on when receiving said FM broadcasting signal; and
a second diode connected between the node between said first two diodes and the ground, which is turned on when receiving said television signal and turned off when receiving said FM broadcasting signal;
and a parallel-tuned circuit which is tuned to the frequencies of said FM broadcasting signal is connected in parallel to said second diode.
2. An input switching circuit for a television tuner according to claim 1, wherein a series-tuned circuit comprising a first capacitor and an inductor is provided between said second input terminal and said second switching circuit, said series-tuned circuit being tuned to the frequencies of said FM broadcasting signal.
3. An input switching circuit for a television tuner according to claim 2, wherein a second capacitor is connected between one end of said series-tuned circuit and the ground, said series-tuned circuit and said second capacitor constituting a low-pass filter at and above the frequencies of said FM broadcasting signal, the cutoff frequency of said low-pass filter being set between the lowest frequency of the VHF high band and the highest frequency of said FM broadcasting signal.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. An integrated circuit for generating a clock signal that is provided to a functional block, comprising:
a maximum power determination unit configured to determine a maximum allowed voltage corresponding to maximum power consumption of the functional block;
a clock control unit configured to generate at least one frequency control signal based on a comparison between the maximum allowed voltage and a detected voltage corresponding to a variance in power consumption of the to functional block, and
a clock generator configured to generate the clock signal, wherein a frequency of the clock signal is adjusted according to the frequency control signal.
2. The integrated circuit of claim 1, wherein the maximum power determination unit includes:
a current consumption determination unit configured to determine maximum current consumption of the functional block based on a power control signal; and
a maximum allowed voltage generation unit configured to generate the maximum allowed voltage based on an output current of the current consumption determination unit.
3. The integrated circuit of claim 2, wherein the current consumption determination unit includes:
a plurality of current sources connected in parallel, wherein the current sources are selectively turned on by the power control signal.
4. The integrated circuit of claim 3, wherein the maximum allowed voltage generation unit includes:
a load for generating the maximum allowed voltage based on a current supplied from at least one selectively turned-on current source of the current sources.
5. The integrated circuit of claim 2, wherein the current consumption determination unit includes:
a current source that is selectively turned on by the power control signal.
6. The integrated circuit of claim 5, wherein a load impedance of the maximum allowed voltage generation unit is adjusted according to the power control signal.
7. The integrated circuit of claim 6, wherein the current consumption determination unit further includes:
an initial allowed voltage determination unit for determining an initial value of the maximum allowed voltage.
8. The integrated circuit of claim 1, wherein the clock control unit includes:
a comparison voltage generator configured to generate a comparison voltage based on the detected voltage; and
a second comparator configured to compare the comparison voltage with the maximum allowed voltage to generate a frequency control signal.
9. The integrated circuit of claim 8, wherein the comparison voltage generator includes:
at least one voltage controlled current source for generating a current based on the detected voltage; and
at least one load for generating the comparison voltage based on the current supplied from the at least one voltage-controlled current source.
10. The integrated circuit of claim 9, wherein a load impedance of the comparison voltage generator is variably adjusted.
11. The integrated circuit of claim 9, wherein the maximum power determination unit further includes:
a current source selection unit that selectively turns on the at least one voltage-controlled current source.
12. The integrated circuit of claim 1, wherein the clock generator includes:
a ring oscillator in which three inverters are serially connected.
13. The integrated circuit of claim 1, wherein the clock generator includes:
a voltage controlled oscillator.
14. The integrated circuit of claim 1, further comprising a voltage to conversion unit configured to convert an external power supply voltage into an internal power supply voltage that is substantially maintained, wherein the functional block consumes an amount of current using the internal power supply voltage.
15. The integrated circuit of claim 14, wherein the voltage conversion unit is further configured to detect a variance in current consumption of the functional block to generate the detected voltage.
16. The integrated circuit of claim 15, wherein the voltage conversion unit includes:
a current detection unit configured to generate a first comparison voltage and the internal power supply voltage based on the variance in current consumption of the functional block; and
a first comparator configured to compare the first comparison voltage with an input reference voltage to generate the detected voltage.
17. A method of generating a crock signal that is provided to a functional block, comprising:
determining a maximum allowed voltage corresponding to maximum power consumption of the functional block,
generating at least one frequency control signal based on a comparison between the maximum allowed voltage and a detected voltage corresponding to a variance in power consumption of the functional block, and
generating the clock signal, wherein a frequency of the clock signal is adjusted according to the frequency control signal.
18. The method of claim 17, wherein the step of determining a maximum allowed voltage includes:
determining the maximum current consumption of the functional block based on a power control signal; and
generating the maximum allowed voltage corresponding to an output current of the current consumption determination unit.
19. The method of claim 18, wherein the step of generating at least one frequency control signal includes:
generating a comparison voltage corresponding to the detected voltage;
comparing the comparison voltage with the maximum allowed voltage; and
generating the frequency control signal based on the comparison between the comparison voltage and the maximum allowed voltage.
20. The method of claim 17, further comprising:
converting an external power supply voltage into an internal power supply voltage that is substantially maintained wherein the functional block consumes an amount of current using the internal power supply voltage; and
detecting a variance in current consumption of the functional block to generate the detected voltage.