Patent ID: 9680379
Date: 2017-06-13
CPC Classifications: H02M

Claim:
1. A direct current to direct current (DC-DC) converter comprising: a voltage converting block that converts an input supply voltage to an output voltage having a target level, the voltage converting block including a power switch which is turned on at on-time of a power driving signal, wherein the input supply voltage is applied through the power switch when the power switch is turned on; a power driving block that generates the power driving signal using an oscillation output signal, wherein a cycle of the power driving signal varies in accordance with a cycle of the oscillation output signal and a length of the on-time of the power driving signal is fixed to a power time regardless of variation of the cycle of the oscillation output signal; a voltage-controlled oscillating block that generates the oscillation output signal, the cycle of the oscillation output signal being controlled according to a level of an oscillation control signal; and a target tracking block that generates a feedback voltage using the output voltage and controls the level of the oscillation control signal such that the feedback voltage follows a target reference voltage to stabilize the output voltage to the target level, wherein the power driving block comprises: a time setting unit that generates a time setting signal using the oscillation output signal, wherein a cycle of the time setting signal varies in accordance with the cycle of the oscillation output signal, and a length of on-time of the time setting signal is fixed to the power time; and a power driving unit that receives the time setting signal and generates the power driving signal, wherein a pull-up voltage of the power driving signal is level-shifted with respect to a pull-up voltage of the time setting signal, wherein the time setting unit comprises: a flip-flop that generates the time setting signal responding to the oscillation output signal and a reset driving signal, wherein the time setting signal is activated in response to the oscillation output signal and deactivated in response to the reset driving signal; and a power-time generating unit that generates the reset driving signal using the time setting signal, the reset driving signal being activated when a time corresponding to the power time elapses from the activation of the time setting signal.