Keeper circuits having dynamic leakage compensation

A keeper circuit for use in a digital circuit powered by a voltage provided between a first supply line and a second supply line, the keeper circuit for selectively maintaining an intermediate node of the digital circuit at a first voltage level, the keeper circuit comprising:

• a keeper transistor having a first conduction terminal, a second conduction terminal, and a modulation terminal, the modulation terminal receiving a signal indicating whether the keeper transistor is to maintain an intermediate node at a first voltage level;
• a first PMOS transistor having a drain terminal, a source terminal, and a gate terminal, one of the source and drain terminals of the first PMOS transistor being coupled to a conduction terminal of the keeper transistor to provide a series circuit of the transistors, the series circuit being coupled between the intermediate node and the first supply line;
• a second PMOS transistor having a drain terminal, a source terminal, and a gate terminal, the second PMOS transistor being coupled to the first PMOS transistor in a current-mirror relationship such that the maximum amount of current conducted by the first PMOS transistor through its drain and source terminals is related to the current conducted by the second PMOS transistor through its source and drain terminals;
• and
• at least a first NMOS transistor having a drain terminal coupled to the drain terminal of the second PMOS transistor, a source terminal, and a gate terminal, wherein the gate terminal and the source terminal are coupled together and to a source of potential.

A keeper circuit for use in a circuit powered by a voltage provided between a first supply line and a second supply line, the keeper circuit for selectively maintaining an intermediate node of the circuit at a first voltage level in opposition to a leakage current being conducted between the intermediate node and the second supply line, the keeper circuit comprising:

• a keeper transistor having a first conduction terminal, a second conduction terminal, and a modulation terminal, the modulation terminal receiving a signal indicating whether the keeper transistor is to maintain an intermediate node at a first voltage level;
• characterized by a current-setting transistor having a first conduction terminal, a second conduction terminal, and a modulation terminal, the current-setting transistor being configured to set the maximum current flow between its first and second conduction terminals in relation to the leakage current being conducted between the intermediate node and the second supply line;
• and
• characterized in that a conduction terminal of the keeper transistor is coupled to a conduction terminal of the current-setting transistor to provide a series circuit of the transistors, and in that the series circuit is coupled between the intermediate node and the first supply line.

A keeper circuit for use in a circuit powered by a voltage provided between a first supply line and a second supply line, the keeper circuit for selectively maintaining an intermediate node of the circuit at a first voltage level in opposition to a leakage current being conducted between the intermediate node and the second supply line, the keeper circuit comprising:

• a keeper transistor having a first conduction terminal, a second conduction terminal, and a modulation terminal, the modulation terminal receiving a signal indicating whether the keeper transistor is to maintain an intermediate node at a first voltage level;
• a sensing network having one or more transistors configured to generate a leakage current that is in relation to the leakage current being conducted between the intermediate node and at least one of the supply lines;
• and
• a current-setting transistor having a first conduction terminal, a second conduction terminal, and a modulation terminal, the current-setting transistor being configured to set the maximum current flow between its first and second conduction terminals in relation to the leakage current generated by the sensing network;
• and
• wherein a conduction terminal of the keeper transistor is coupled to a conduction terminal of the current-setting transistor to provide a series circuit of the transistors, and wherein the series circuit is coupled between the intermediate node and the first supply line.