Discharge circuit for voltage multipliers

A circuit, comprising:

• a charge pump configured to generate a discharge current during a discharge phase;
• an evacuating circuit coupled to the generator circuit for evacuating the electric charge stored in the charge pump during a corresponding portion of the discharge phase, said evacuating circuit including a first discharge circuit branch and a second discharge circuit branch coupled to the charge pump, said evacuating circuit being configured to cause the discharge current flowing through the first discharge circuit branch, during the portion of the discharge phase of the corresponding circuit node, when the pump voltage of the charge pump is higher than a respective threshold, and through the second discharge circuit branch when the pump voltage of the charge pump is lower than said respective threshold;
• wherein the first circuit branch includes a first transistor of a first type of conductivity and a second transistor of a second type of conductivity opposite to the first;
• and
• wherein the charge pump further comprises a plurality of circuit nodes having an ordered sequence from a first circuit node, such that during the operational phase of the charge pump, the pump voltage of each circuit node except the first being greater, in absolute value, than the pump voltage of the previous circuit node in the sequence, the portion of the discharge phase corresponding to each circuit node starting when the pump voltage of the next circuit node in the sequence results to be lower than the respective threshold of said next circuit node.

A method, comprising:

• generating a discharge current during a discharge phase having portions;
• evacuating accumulated electric charge in a charge pump during a corresponding portion of the discharge phase, said evacuating during each portion of the discharge phase including:
• causing an initial portion of the discharge current to flow through a first discharge circuit branch having at least two transistors of opposite conductivity, such that during the portion of the discharge phase, when the voltage of a corresponding control node is higher than a respective threshold, and
• causing a subsequent potion of the discharge current to flow through a second discharge circuit branch that is cross coupled to the first discharge branch when the voltage of the corresponding control node is lower than said respective threshold and in response to the second discharge current from the discharge circuit.

A discharger, comprising:

• an input node;
• first and second intermediate nodes;
• a first branch having at least one transistor and having at least one diode, the first branch coupled between the input node and first intermediate node and configured to conduct a first discharge current during a first portion of a discharge period;
• and
• a second branch cross-coupled with the first branch and coupled between the input node and second intermediate node and configured to conduct a second discharge current during a second portion of the discharge period;
• wherein the at least one transistor in the first branch is coupled to the second branch and the at least one transistor in the second branch is coupled to the first branch.

A discharger, comprising:

• an input node;
• first and second intermediate nodes;
• a first branch having at least one transistor and having at least one diode, the first branch coupled between the input node and first intermediate node and configured to conduct a first discharge current during a first portion of a discharge period;
• and
• a second branch coupled between the input node and second intermediate node and configured to conduct a second discharge current during a second portion of the discharge period;
• wherein the first branch includes:
• a first transistor of a first type having a first conduction node coupled to the input node, a second conduction node, and a control node coupled to the second intermediate node;
• a diode having a first node coupled to the second conduction node of the first transistor and having a second node;
• and
• a second transistor of a second type having a first conduction node coupled to the second node of the diode, a second conduction node coupled to the first intermediate node, and a control node coupled to the second intermediate node.

A discharger, comprising:

• an input node;
• first and second intermediate nodes;
• a first branch having at least one transistor and having at least one diode, the first branch coupled between the input node and first intermediate node and configured to conduct a first discharge current during a first portion of a discharge period;
• and
• a second branch coupled between the input node and second intermediate node and configured to conduct a second discharge current during a second portion of the discharge period;
• wherein the first branch includes:
• a first transistor of a first type having a first conduction node coupled to the input node, a second conduction node, and a control node coupled to the second branch;
• a diode having a first node coupled to the second conduction node of the first transistor and having a second node;
• and
• a second transistor of a second type having a first conduction node coupled to the second node of the diode, a second conduction node coupled to the first intermediate node, and a control node coupled to the second branch.

A discharger, comprising:

• an input node;
• first and second intermediate nodes;
• a first branch having at least one transistor and having at least one diode, the first branch coupled between the input node and first intermediate node and configured to conduct a first discharge current during a first portion of a discharge period;
• and
• a second branch coupled between the input node and second intermediate node and configured to conduct a second discharge current during a second portion of the discharge period;
• wherein the first branch includes:
• a first transistor of a first type having a first conduction node coupled to the input node, a second conduction node, and a control node coupled to the second intermediate node;
• a first diode having a first node coupled to the second conduction node of the first transistor and having a second node;
• a second diode having a first node coupled to the second node of the first diode and having a second node;
• and
• a second transistor of a second type having a first conduction node coupled to the second node of the second diode, a second conduction node coupled to the first intermediate node, and a control node coupled to the second intermediate node.

A discharger, comprising:

• an input node;
• first and second intermediate nodes;
• a first branch having at least one transistor and having at least one diode, the first branch coupled between the input node and first intermediate node and configured to conduct a first discharge current during a first portion of a discharge period;
• and
• a second branch coupled between the input node and second intermediate node and configured to conduct a second discharge current during a second portion of the discharge period;
• the discharger further comprising:
• a third intermediate node;
• and
• wherein the first branch includes
• a first transistor of a first type having a first conduction node coupled to the input node, a second conduction node, and a control node coupled to the second intermediate node;
• a diode having a first node coupled to the second conduction node of the first transistor and having a second node;
• a second transistor of a second type having a first conduction node coupled to the second node of the diode, a second conduction node, and a control node coupled to the second intermediate node;
• and
• a third transistor of the second type having a first conduction node coupled to the second conduction node of the second transistor, a second conduction node coupled to the first intermediate node, and a control node coupled to the third intermediate node.

An integrated circuit, comprising:

• a charge pump having a first pump output node;
• and
• a discharger, including
• a discharger input node coupled to the pump output node;
• first and second discharger intermediate nodes;
• a first branch having at least one transistor and having at least one diode, the first branch coupled between the discharger input node and first discharger intermediate node and configured to conduct a first discharge current during a first portion of a discharge period;
• and
• a second branch cross-coupled with the first branch and coupled between the discharger input node and second discharger intermediate node and configured to conduct a second discharge current during a second portion of the discharge period;
• wherein the at least one transistor in the first branch is coupled to the second branch and the at least one transistor in the second branch is coupled to the first branch.

A system, comprising:

• a first integrated circuit, including
• a charge pump having a first pump output node;
• and
• a discharger, including
• a discharger input node coupled to the pump output node;
• first and second discharger intermediate nodes;
• a first branch having at least one transistor and having at least one diode, the first branch coupled between the discharger input node and first discharger intermediate node and configured to conduct a first discharge current during a first portion of a discharge period;
• and
• a second branch cross-coupled with the first branch and coupled between the discharger input node and second discharger intermediate node and configured to conduct a second discharge current during a second portion of the discharge period;
• wherein the at least one transistor in the first branch is coupled to the second branch and the at least one transistor in the second branch is coupled to the first branch;
• and
• a second integrated circuit coupled to the first integrated circuit.

A method, comprising:

• partially discharging a charge pump at a first rate;
• discharging the charge pump at a second rate after partially discharging the charge pump at the first rate;
• and
• inactivating the charge pump before discharging the charge pump at the first and second rates.