Current sense circuit apparatus for power amplifier control

A method for controlling the power output of a power amplifier such that the power output is substantially equal to a predetermined power setting wherein the power amplifier draws power from a variable power source and receives an input from an exciter, said method comprising the step of:

• drawing a first current from variable power source toward and into the power amplifier;
• drawing a second current from variable power source toward and into a control circuit, wherein the first current is a multiple of the second current;
• converting the second current to a first voltage;
• comparing the first voltage with the predetermined power setting so as to create a second voltage;
• and
• applying the second voltage to bias the exciter or the power amplifier toward altering the power output of the power amplifier.

A power control system for controlling the power output of a power amplifier, said power control system drawing power from a variable voltage supply, such as a battery, and receiving a signal input for indicating the desired power output, said power control system comprising:

• power amplifier means for amplifying an electrical signal, said power amplifier means drawing a current from said variable voltage supply, said power amplifier means of the type wherein said drawn current is indicative of the power output from said power amplifier means;
• current sense means operably connected between the variable voltage supply and the power amplifier means for sensing the current drawn by the power amplifier and for simultaneously producing an output current, wherein said output current is directly correlated to said sensed current, said current sense means being configured so as to minimize the voltage drop between the power amplifier means and the variable source voltage to, in turn, minimize the draw on the variable voltage supply;
• and
• control means operably accepting said output current and the signal input for comparing said output current to said signal input so as to produce a control signal for controlling the power output by said power amplifier means.

A power control system for controlling the power output of a power amplifier, said power control system drawing power from a variable voltage supply, such as a battery, and receiving a signal input for indicating the desired power output, said power control system comprising:

• a power amplifier that draws a current from said variable voltage supply having an input and an output, said power amplifier of the type wherein said drawn current is indicative of the power output from said power amplifier;
• an excitor circuit having an input and an output, said excitor circuit output being operably connected to said power amplifier input;
• a first transistor having a first emitter, first collector and first base, said first transistor being located between the variable voltage supply and said power amplifier and having a first current flowing therethrough;
• a second transistor having a second emitter, second collector and second base, said second transistor having a second current flowing therethrough;
• said first and second emitters being electrically connected to the variable voltage supply;
• said first and second bases being electrically coupled to each other and further coupled to said first collector;
• and
• control means operably connected to said second collector and the signal input for comparing said second current to said signal input so as to produce a control signal for controlling the power output by said power amplifier.

A power control system for controlling the power output of a power amplifier, said power control system drawing power from a variable voltage supply, such as a battery, and receiving a signal input for indicating the desired power output, said power control system comprising:

• power amplifier means for amplifying an electrical signal, said power amplifier means drawing a current from said variable voltage supply, said power amplifier means of the type wherein said drawn current is indicative of the power output from said power amplifier means;
• current sense means operably connected between the variable voltage supply and said power amplifier means for sensing the current drawn by the power amplifier and for simultaneously producing an output current, wherein said output current is directly correlated to said sensed current;
• a comparator transistor having its base electrically connected to a voltage set point, its emitter connected to said indicative output;
• a protection resistor operably connected between the collector of said comparator transistor and the exciter so as to protect the bias control transistor of the exciter;
• a charge-up resistor operably connected between a supply voltage and said protection resistor, said supply voltage being greater than said sensed voltage and further being supplied to the exciter;
• and
• a capacitor operably connected between said protection resistor and ground, so as to prevent oscillation of said apparatus by providing a delay in combination with said charge-up resistor and said protection resistor.