High voltage reference and measurement circuit for verifying a programmable cell

A circuit for providing a verifying voltage signal comprising:

• a step up circuit having an input coupled to a programming voltage and an output for providing a verifying voltage, said verifying voltage being higher than said programming voltage;
• a programmable cell having a test input;
• and
• a first switch having (a) an input coupled to the output of said step down circuit and (b) an output that presents said output of said step down circuit to said test input when a control input is at a first digital state and does not present said verifying voltage to said test input when said control input is at a second digital state.

A method for presenting a verifying voltage to a programmable cell, comprising the steps of:

• (a) receiving a programming voltage in a means for altering a power supply level;
• (b) presenting an output from said means for altering a power supply level to a switching means, said output being different from said programming voltage;
• and
• (c) presenting said output of said altering means to a programming cell when a control signal is at a first digital state and not presenting said output of said altering means to said programming cell when said control signal is at a second digital state.

A circuit for verifying the programming of a programmable cell, comprising:

• (a) means for altering a power supply level;
• (b) said programmable cell;
• and
• (c) switching means for (i) transmitting said signal from said means for altering a power supply level to said programming cell in response to a control signal at a first digital state and (ii) not transmitting said signal from said means for altering a power supply level to said programming cell when said control signal is at a second digital state.