Transconductance amplifier having sensfets which drive a load with linearly proportional current
First Claim
Patent Images
1. A transconductance amplifier which drives a load with current which is linearly proportional to an input signal comprising:
- two sensfet semiconductor devices, each having a source pin, a drain pin, a gate pin, a mirror pin, and a Kelvin pin, said sensfet devices being of the type in which the current flowing between said source and said drain is controlled by said gate pin, and the current from said mirror pin is a small fraction of the current between said source pin and said drain pin;
a source of power current for each of said sensfet devices, each source of current and said load being connected with said source pins and said drain pins so that said sensfet devices control the flow of current through said load, said sensfet devices being connected as an H bridge amplifier with said load being connected between the drain pins of said sensfet devices;
said input signal being applied to said gate pins;
source means for producing a sense current connected to said mirror pins, said sense current being linearly proportional to said current through said load; and
negative feedback means connected between said source of sense current and said gate pins to apply negative feedback to said gate pins to maintain the current flow through said load linearly proportional to said input voltage.
2 Assignments
0 Petitions
Accused Products
Abstract
A transconductance amplifier has sensfets connected to an H bridge configuration to drive a load with current which is linearly proportional to the input signal. A inverting or a non-inverting side is active depending upon whether the signal is above or below a reference. Three stages include power amplifiers, switches and comparators for turning the two sides on and off. A mirror current source for each sensfet provides feedback to maintain the linearity of the load current as a function of input signal, thus eliminating the need for a resistor in the current path for sensing the feedback.
-
Citations
8 Claims
-
1. A transconductance amplifier which drives a load with current which is linearly proportional to an input signal comprising:
-
two sensfet semiconductor devices, each having a source pin, a drain pin, a gate pin, a mirror pin, and a Kelvin pin, said sensfet devices being of the type in which the current flowing between said source and said drain is controlled by said gate pin, and the current from said mirror pin is a small fraction of the current between said source pin and said drain pin; a source of power current for each of said sensfet devices, each source of current and said load being connected with said source pins and said drain pins so that said sensfet devices control the flow of current through said load, said sensfet devices being connected as an H bridge amplifier with said load being connected between the drain pins of said sensfet devices; said input signal being applied to said gate pins; source means for producing a sense current connected to said mirror pins, said sense current being linearly proportional to said current through said load; and negative feedback means connected between said source of sense current and said gate pins to apply negative feedback to said gate pins to maintain the current flow through said load linearly proportional to said input voltage. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
-
Specification