A driving circuit for a single-string light-emitting diode (LED) lamp includes a push-pull converter. The push-pull converter converts an input low DC voltage (such as 12-19V) to a high DC voltage (such as above 200V) to supply power to the single-string LED lamp. The driving circuit controls a lamp current flowing through the single-string LED lamp by constant current and adjusts brightness of the single-string LED lamp by pulse-width modulation (PWM) dimming. In addition, the single-string LED lamp provides the standardization design for connectors of the driving circuit used to connect to the single-string LED lamp so that the driving circuit has a better common-use characteristic. Moreover, the driving circuit does not need a current balance circuit and only needs a cheaper and general-purpose integrated circuit to control the push-pull converter to reduce design cost of the driving circuit.