Lighting circuit and the lamp

Lighting circuit 1 includes a control integrated circuit U1 for turning on and off the switching element Q1, primary coil T11 connected in series to the switching element Q1 and the transformer T1 and a secondary coil T12, across the primary coil T11 comprising of a first voltage supply circuit for supplying to the LED module 2 voltage, and a second voltage supply circuit for supplying a voltage induced in the secondary coil T12 to the power supply terminal Vcc when the switching element Q1 is turned on. The turns ratio N of the primary coil T11 for the number of turns of the secondary coil T12 is the voltage supplied from the AC power supply X1 [V], the maximum value of the guaranteed operating range of the power supply voltage of the control unit Y [V], When the minimum value of the guaranteed operating range of the power supply voltage of the control unit and Z [V], a relationship expressed by [Equation 1]. [Number 1]