A power supply including a power converter circuit operated in a constant ON-time control mode, the power supply comprising: a reference voltage generator circuit operable to produce a varying reference voltage; a ramp generator circuit operable to produce a ramp voltage signal, a magnitude of which is offset by the varying reference voltage; and a control circuit operable to control activation of switch circuitries of the power converter circuit to generate an output voltage to power a load based on a magnitude of the ramp voltage signal with respect to an output voltage feedback signal of the power supply, characterized in that the reference voltage generator circuit further includes: a bias circuit (R2, 220) configured to bias the varying reference voltage towards a bias voltage value over time, a transconductance amplifier configured to compare a magnitude of the output voltage feedback signal to a received reference voltage, the transconductance amplifier operable to generate an output current, a magnitude of which depends on a difference between the magnitude of the output voltage feedback signal and the received reference voltage, and a capacitor, the capacitor operable to receive the output current generated by the transconductance amplifier to produce the varying reference voltage, wherein the bias circuit (R2, 220) is coupled to the capacitor and is configured to apply a bias current to the capacitor. a reference voltage generator circuit operable to produce a varying reference voltage; a ramp generator circuit operable to produce a ramp voltage signal, a magnitude of which is offset by the varying reference voltage; and a control circuit operable to control activation of switch circuitries of the power converter circuit to generate an output voltage to power a load based on a magnitude of the ramp voltage signal with respect to an output voltage feedback signal of the power supply, characterized in that the reference voltage generator circuit further includes: a bias circuit (R2, 220) configured to bias the varying reference voltage towards a bias voltage value over time, a transconductance amplifier configured to compare a magnitude of the output voltage feedback signal to a received reference voltage, the transconductance amplifier operable to generate an output current, a magnitude of which depends on a difference between the magnitude of the output voltage feedback signal and the received reference voltage, and a capacitor, the capacitor operable to receive the output current generated by the transconductance amplifier to produce the varying reference voltage, wherein the bias circuit (R2, 220) is coupled to the capacitor and is configured to apply a bias current to the capacitor. a bias circuit (R2, 220) configured to bias the varying reference voltage towards a bias voltage value over time, a transconductance amplifier configured to compare a magnitude of the output voltage feedback signal to a received reference voltage, the transconductance amplifier operable to generate an output current, a magnitude of which depends on a difference between the magnitude of the output voltage feedback signal and the received reference voltage, and a capacitor, the capacitor operable to receive the output current generated by the transconductance amplifier to produce the varying reference voltage, wherein the bias circuit (R2, 220) is coupled to the capacitor and is configured to apply a bias current to the capacitor.