The present disclosure discloses a LED driving device and a control method for the same. The LED driving device includes a conversion unit, a dimming switch circuit and a control unit. The control unit includes a dimming control unit and a conversion control unit. The dimming control unit includes a comparison circuit, a constant-voltage dimming circuit and a constant-current dimming circuit. The comparison circuit compares a first signal that represents an output voltage output from the conversion unit with a reference signal, and outputs a first enabling signal and a second enabling signal. The constant-voltage dimming circuit receives the first enabling signal, and outputs a first driving signal to at least one second switch to perform constant-voltage dimming; and the constant-current dimming circuit receives the second enabling signal, and outputs a current-reference to the conversion control unit to perform constant-current dimming.