A system comprising: a low drop-out, LDO, regulator configured to receive a supply voltage at an input terminal and provide an output voltage at an output terminal based on a function of the supply voltage, the LDO regulator configured to be switchable between at least a first mode and a second mode, wherein the first and second modes each define the output voltage provided to the output terminal based on different functions of the supply voltage; a digital logic controller configured to select the mode of the LDO regulator by providing control signalling to the LDO regulator, the digital logic controller configured to receive power for the provision of the control signalling from the output voltage provided by the LDO regulator; and characterised by comprising: a level shifter configured to provide for shifting of voltage levels of the control signalling provided by the digital logic controller to the LDO regulator; wherein the LDO regulator comprises LDO start-up circuitry configured to control the level shifter to cause the LDO regulator, during start-up, to default to a predetermined one of the first and second mode and thereby prevent the digital logic controller from controlling the mode of the LDO regulator, and wherein the LDO start-up circuitry is further configured to monitor the voltage at the output terminal of the LDO regulator and, based on the monitored voltage being below a threshold, control the level shifter to cause the LDO regulator to default to the predetermined one of the first and second mode and thereby prevent the digital logic controller from controlling the mode of the LDO regulator. a low drop-out, LDO, regulator configured to receive a supply voltage at an input terminal and provide an output voltage at an output terminal based on a function of the supply voltage, the LDO regulator configured to be switchable between at least a first mode and a second mode, wherein the first and second modes each define the output voltage provided to the output terminal based on different functions of the supply voltage; a digital logic controller configured to select the mode of the LDO regulator by providing control signalling to the LDO regulator, the digital logic controller configured to receive power for the provision of the control signalling from the output voltage provided by the LDO regulator; and characterised by comprising: a level shifter configured to provide for shifting of voltage levels of the control signalling provided by the digital logic controller to the LDO regulator; wherein the LDO regulator comprises LDO start-up circuitry configured to control the level shifter to cause the LDO regulator, during start-up, to default to a predetermined one of the first and second mode and thereby prevent the digital logic controller from controlling the mode of the LDO regulator, and wherein the LDO start-up circuitry is further configured to monitor the voltage at the output terminal of the LDO regulator and, based on the monitored voltage being below a threshold, control the level shifter to cause the LDO regulator to default to the predetermined one of the first and second mode and thereby prevent the digital logic controller from controlling the mode of the LDO regulator. a level shifter configured to provide for shifting of voltage levels of the control signalling provided by the digital logic controller to the LDO regulator; wherein the LDO regulator comprises LDO start-up circuitry configured to control the level shifter to cause the LDO regulator, during start-up, to default to a predetermined one of the first and second mode and thereby prevent the digital logic controller from controlling the mode of the LDO regulator, and wherein the LDO start-up circuitry is further configured to monitor the voltage at the output terminal of the LDO regulator and, based on the monitored voltage being below a threshold, control the level shifter to cause the LDO regulator to default to the predetermined one of the first and second mode and thereby prevent the digital logic controller from controlling the mode of the LDO regulator.