Ramp circuit and direct current (DC)-DC converter thereof
AssigneeMagnaChip Semiconductor, Ltd.
InventorsJun Sik Min, Hyoung Kyu Kim, Tae Kyoung Kang
Life of this patent
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Abstract
Provided are a ramp circuit and a DC-DC converter. The ramp circuit generates a current flowing in a resistor using voltages affected by an output voltage and an input voltage of a DC-DC converter, and generates a ramp signal through copying of the current and charging and discharging of a capacitor using a current mirror unit. The ramp signal is generated by considering the input voltage and the output voltage, and thus the ramp signal has an optimal slope to provide an adaptive response to state change in the input voltage and the output voltage. The DC-DC converter uses such a ramp circuit to facilitate its operation.
Claims20
A ramp circuit, comprising:
- a first amplifier configured to receive a first voltage corresponding to an output voltage;
- a second amplifier configured to receive a second voltage corresponding to an input voltage;
- a resistor provided between output terminals of the first amplifier and the second amplifier;
- a current mirror unit configured to copy a current value that flows in the resistor;
- and
- an output unit configured to control a current output from the current mirror unit into a capacitor to output a ramp signal through an output terminal of the output unit.
A direct current (DC)-DC converter comprising:
- a ramp circuit configured to vary a slope of a ramp signal according to an input voltage and an output voltage and output the ramp signal;
- a comparator configured to receive a signal in which the ramp signal and a sensing signal of an inductor are combined through a non-inverting (+) terminal, and configured to receive an output signal of an error amplifier through an inverting (−) terminal;
- a logic device configured to generate a pulse width modulation (PWM) signal according to an output signal of the comparator and a clock signal;
- and
- a power switch configured to turn on and off by the PWM signal.
A ramp circuit, comprising:
- a resistor provided between output terminals of a first amplifier configured to receive a first voltage corresponding to an output voltage and a second amplifier configured to receive a second voltage corresponding to an input voltage;
- a current mirror unit configured to copy a current value that flows in the resistor;
- and
- an output unit configured to control a current output from the current mirror unit into a capacitor to output a ramp signal through an output terminal of the output unit.
Dependencies are inferred from the claim text.