Discharge circuit for voltage multipliers

摘要

An embodiment of a discharge circuit for evacuating electric charge accumulated in circuit nodes of a charge pump during a discharge phase consequent to a shutdown of the charge pump is proposed. The charge pump is configured to bias each circuit node with a corresponding pump voltage during an operational phase of the charge pump. The discharge circuit includes a generator circuit configured to generate a discharge current during the discharge phase. The discharge circuit further includes means for evacuating the electric charge stored in each circuit node of the charge pump during a corresponding portion of the discharge phase; such means for evacuating include a respective discharge stage for each circuit node of the charge pump. Each discharge stage includes a first discharge circuit branch and a second discharge circuit branch coupled to the corresponding circuit node. The discharge stage is 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 corresponding circuit node is higher than a respective threshold, and through the second discharge circuit branch when the pump voltage of the corresponding circuit node is lower than said respective threshold.

主权项

1. 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 such that the first discharge branch and the second discharge branch are cross coupled, said evacuating circuit being configured to cause an initial portion of the discharge current 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 a subsequent portion of the discharge current 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 is responsive to the subsequent portion of the discharge current from the second circuit branch.