Patent ID: 6949952

Claim:
A programming circuit for selectively either isolating a programming node from an external terminal of an integrated circuit or allowing a programming voltage to be coupled from the external terminal to the programming node, the programming circuit comprising: an isolation device coupled between the external terminal and the programming node, the isolation device having a first terminal coupled to the external terminal, a second terminal coupled to the programming node, and control terminal, the isolation device being operable to couple the programming voltage applied to the external terminal to the programming node as long as the absolute value of the voltage coupled to the programming node is within a predetermined magnitude of a control voltage applied to the control terminal of the isolation device; and a charge pump circuit having a power input coupled to the external terminal and an output terminal coupled to the control terminal of the isolation device, the charge pump circuit being coupled to receive the programming voltage applied to the external terminal and being operable in a program mode to increase the absolute value of the programming voltage in response to a program command signal to generate the control voltage, the charge pump circuit being operable in an isolation mode to generate as the control voltage a voltage having an absolute value that is substantially less than the absolute value of the programming voltage, the charge pump circuit comprising: a capacitive device having a first lead and a second lead coupled to receive the programming voltage; a boosting circuit repetitively driving the first lead of the capacitive device between first and second voltage levels responsive to the program command signal; and a uni-directional current path coupling the second lead of the capacitive device to the control terminal of the isolation device.