Leakage compensation circuit using limiting current inverter
The leakage compensation circuit includes: a replica circuit of a circuit to be compensated, the replica circuit provides a replica leakage current equal to a leakage current of the circuit to be compensated; an amplifier having a first input coupled to the replica circuit and a second input coupled to a node to be compensated; a first resistance coupled between an output of the amplifier and the replica circuit; a second resistance coupled between the output of the amplifier and the node to be compensated; and wherein the replica leakage current is subtracted from the node to be compensated.
1. A leakage compensation circuit comprising:
a replica circuit of a circuit to be compensated, the replica circuit provides a replica leakage current equal to a leakage current of the circuit to be compensated;
an amplifier having a first input coupled to the replica circuit and a second input coupled to a node to be compensated;
a first resistance coupled between an output of the amplifier and the replica circuit;
a second resistance coupled between the output of the amplifier and the node to be compensated; and
wherein the replica leakage current is subtracted from the node to be compensated and the leakage compensation circuit compensates for the leakage current without using a current mirror.
2. The circuit of claim 1 wherein the first input of the amplifier is a negative input and the second input is a positive input.
3. The circuit of claim 1 wherein the first resistance is equal to the second resistance.
4. A circuit having leakage current compensation comprising:
a leaky circuit;
a replica circuit of the leaky circuit, the replica circuit provides a replica leakage current equal to a leakage current of the leaky circuit;
an amplifier having a first input coupled to the replica circuit and a second input coupled to a current leakage node of the leaky circuit; a first resistance coupled between an output of the amplifier and the replica circuit; a second resistance coupled between the output of the amplifier and the current leakage node; and
wherein the replica leakage current cancels the leakage current of the leaky circuit and the circuit compensates for the leakage current without using a current mirror.
5. The circuit of claim 4 wherein the first input of the amplifier is a negative input and the second input is a positive input.
6. The circuit of claim 4 wherein the first resistance is equal to the second resistance.
7. A circuit having leakage current compensation comprising:
a compensation node for receiving a current from a leaky circuit;
a current inverter having an input and an output, the output coupled to the compensation node;
a replica of the leaky circuit having an output coupled to the input of the current inverter and operative for producing a compensation current equal to the current from the leaky circuit,
wherein the current inverter is operative for producing a current on the output with a polarity that is opposite than a polarity received at its input but equal in magnitude, and
the current inverter comprising an amplifier and at least a first resistor and a second resistor.
8. The circuit of claim 7 wherein the amplifier is a high-gain, operational amplifier and there is a linear relationship between an offset voltage and difference between the compensation and the current from the leaky circuit.
9. The circuit of claim 7 wherein the resistances associated with the two resistors are equal and very high.
10. The circuit of claim 9 wherein the resistors comprise transistors operating in a cutoff region.
11. The circuit of claim 7 wherein the amplifier has a first input coupled to the input of the current inverter and the amplifier has a second input coupled to the compensation node.
12. The circuit of claim 7 wherein the amplifier has an output, and the first resistor is coupled between the first input of the amplifier and the output of the amplifier.
13. The circuit of claim 12 wherein the amplifier has an output, and the second resistor is coupled between the compensation node and the output of the amplifier.