An LED power supply, comprising: a power factor correction circuit configured to receive an input signal and provide a DC bus voltage across a DC bus; a converter configured to receive the DC bus voltage and to output a DC output voltage for powering at least one LED, wherein the converter comprises a high-side transistor, wherein the high-side transistor is OFF when the LED power supply is in standby; a voltage sensor being configured to output a voltage sensor output; and a controller configured to receive the voltage sensor output and to output a control signal according to the voltage sensor output, wherein the voltage sensor is positioned in series with the output of the high-side transistor, such that, when the high-side transistor is ON, the voltage sensor output is proportional to the DC bus voltage, and when the transistor is OFF, the voltage sensor is disconnected from the DC bus.