A charge pump circuitry for generating a charging voltage for programming a one time programmable (OTP) memory includes a charge pump sub-circuit for generating the charging voltage in a second voltage range when the charging voltage exceeds a threshold level. A precharge circuit generates the charging voltage in a first voltage range when the charging voltage is below the threshold level. A voltage measurement circuit determines the charging voltage. A first control circuit enables the precharge circuit and disables the charge pump sub-circuit in a first mode of operation responsive to the charging voltage being determined to be below the threshold level and disables the precharge circuit and enables the charge pump sub-circuit in a second mode of operation responsive to the charging voltage being determined to exceed the threshold level. A second control circuit provides an indication that the charging voltage has reached a charging level for programming the OTP memory responsive to the determined charging voltage.