LNB control circuit that provides power and control commands

1. A control circuit comprising:

an inductor electrically connected to a first node;

a first capacitor electrically connected between the first node and ground, the first capacitor reducing switching noise of a power supply;

a second capacitor electrically connected between the first node and a second node, the second capacitor controlling a bidirectional data path by selectively presenting high or low impedance at an output pin;

a first resistor electrically connected to the second node; and a field effect transistor comprising a body terminal, a source terminal, a gate terminal and a drain terminal, wherein the drain terminal is electrically connected to the first resistor, the body terminal and the source terminal are electrically connected to ground, and the field effect transistor selectively coupling the second capacitor to ground in response to receiving a transistor-transistor level voltage enable signal at the gate terminal of the field effect transistor.

2. The control circuit of claim 1 further comprising:

an enable input pin electrically connected to the gate terminal of the field effect transistor, wherein the transistor-transistor level voltage enable signal is inputted on the enable input pin to control flow of current through the field effect transistor and thereby control the impedance level at the first node.

3. The control circuit of claim 2 further comprising:

a carrier insert pin coupled to a microprocessor; and

a power input coupled to the power supply; wherein the microprocessor and the power supply are components of a set-top box.

4. The control circuit of claim 3 wherein the enable signal is transmitted to the control circuit by the microprocessor.

5. The control circuit of claim 3 wherein the control signal is inputted at the carrier insert pin and the power supply signal is inputted at the power input.

6. The control circuit of claim 5 wherein the control signal and the power signal are combined and outputted at the first node.

7. The control circuit of claim 1 further comprising:

a second resistor electrically connected to the second node.

8. An apparatus for controlling a low noise block comprising:

an RF splitter coupled to the low noise block, the RF splitter splitting a signal into a television signal and a communication signal; and

a control circuit coupled to the RF splitter, the control circuit comprising:

a power signal input pin;

a control signal input pin;

an output pin;

an enable signal input pin;

a first capacitor coupled to the power signal input pin and reducing switching noise of a power supply;

a second capacitor coupled to the output pin and controlling a bidirectional data path by selectively presenting high or low impedance at the output pin; and

a field effect transistor comprising a gate terminal, the field effect transistor configured to control the impedance level at the output pin by selectively coupling the second capacitor to ground in response to receiving a transistor-transistor level voltage signal at the gate terminal of the field effect transistor from the enable signal input pin;

wherein the RF splitter is coupled to the control circuit at the output pin of the control circuit.

9. The apparatus of claim 8 further comprising:

a microprocessor coupled to the control signal input pin of the control circuit, wherein the microprocessor inputs a control signal on the control signal input pin.

10. The apparatus of claim 9 further comprising:

a power supply module coupled to the power signal input pin of the control circuit, wherein the power supply module inputs a power signal on the powers signal input pin.

11. The apparatus of claim 10 wherein the microprocessor inputs an enable signal on the enable signal input pin.

12. The apparatus of claim 11 wherein a high enable signal causes a low impedance level at the output pin, the low impedance level facilitating transmission of a combined power and control signal at the output pin.

13. The apparatus of claim 11 wherein a low enable signal causes a high impedance level at the output pin, the high impedance level facilitating the receipt of a communication signal from the low noise block to the control circuit.

14. The apparatus of claim 10 wherein the power supply module is a switch mode converter power supply.

15. A method for communicating with a low noise block comprising:

inputting a power signal to a control circuit;

inputting a control signal to the control circuit;

controlling an impedance level at an output pin by selectively receiving a transistor-transistor level (TTL) enable signal at a gate terminal of a field-effect transistor device that selectively couples a capacitor to ground in response to receiving the TTL enable signal; and

outputting a combined power and control signal to the low noise block.

16. The method of claim 15 further comprising:

inputting a low TTL enable signal to the base terminal of the field-effect transistor device; and

receiving a communication signal from the low noise block.

17. The method of claim 15 further comprising:

attenuating high frequency signals past a cutoff frequency in the power signal.

18. The method of claim 15 wherein the control signal and the enable signal are generated by a microprocessor.

19. The method of claim 15 wherein the combined power and control signal provide power to the low noise block and control the functions of the low noise block.