A multiple-time programmable (MTP) structure is provided that can operate using a power supply with a supply voltage of 1.5 V to 5.5 V. When the supply voltage is above a first voltage, a first circuit is configured to induce a second constant voltage at a drain of a second transistor, and to induce the second constant voltage on a terminal in a third circuit. In some embodiments, the third circuit provides a third constant voltage on a gate of a third transistor. When the supply voltage is below the first voltage, a fifth circuit is configured to induce a fourth constant voltage on a terminal in the third circuit. The fourth constant voltage is substantially equal to the second constant voltage.