DCDC converter with soft-startup and soft-transition for adjustable output voltage
View Patent ↗A method and exemplary apparatus that incorporate soft-start circuit together with adjustable output voltage control are introduced. By implementing a gradual increment of voltage steps/fast decrement, it can totally eliminate overshoot and limit in-rush current significantly at the initial startup and output voltage transition that happens after startup.
1. A DC-DC converter, comprising:
a plurality of resistors connected in series;
a voltage source connected to an end of the plurality of resistors;
a plurality of switches connected to said plurality of resistors, a first end of each of the plurality of switches connected to a first end of a corresponding resistor in the plurality of resistors;
a voltage output terminal connected to a second end of each of the plurality of switches;
a capacitor coupled to the voltage output terminal;
a target voltage generator that sets a target voltage; and
a controller coupled to each of the plurality of switches, the controller sequentially applying turn-on pulses to the plurality of switches to produce an output voltage at the voltage output terminal that gradually increases in a step-wise manner until the output voltage corresponds to the target voltage.
2. A DC-DC converter, comprising:
a plurality of resistor-switch pairs connected in parallel between a first junction and a second junction, each of the plurality of resistor-switch pairs including a resistor and a switch connected in series;
an amplifier including an inverting input connected to the first junction, a non-inverting input, and an amplifier output connected to the second junction;
a reference voltage generator connected to the non-inverting input;
a voltage output terminal connected to the amplifier output;
a capacitor coupled to the voltage output terminal;
a target voltage generator which sets a target voltage; and
a controller coupled to the switch of each of the plurality of resistor-switch pairs, the controller sequentially applying turn-on pulses to the switch of the plurality of resistor-switch pairs to produce an output voltage at the voltage output terminal that gradually increases in a step-wise manner until the output voltage corresponds to the target voltage.
3. A DC-DC converter according to claim 2 , wherein a resistance of the resistor of each of the plurality of resistor-switch pairs is the same.
4. A DC-DC converter according to claim 3 , wherein a first turn-on pulse of the switch of one of the plurality of resistor-switch pairs overlaps with a second turn-on pulse of the switch of an other of the plurality of resistor-switch pairs.
5. A DC-DC converter according to claim 2 , wherein a resistance of the resistor of each of the plurality of resistor-switch pairs is different.
6. A DC-DC converter according to claim 5 , wherein a first turn-on pulse of the switch of one of the plurality of resistor-switch pairs does not overlap with a second turn-on pulse of the switch of an other of the plurality of resistor-switch pairs.
7. A DC-DC converter, comprising:
a plurality of resistor-switch pairs connected in parallel between a first junction and a second junction, each of the plurality of resistor-switch pairs including a first resistor and a switch connected in series, the first junction being connected to a ground;
an amplifier having an inverting input connected to the second junction, a non-inverting input, and an amplifier output;
a second resistor connected between the inverting input and the amplifier output;
a reference voltage generator connected to the non-inverting input;
a voltage output terminal connected to the amplifier output;
a capacitor coupled to the voltage output terminal;
a target voltage generator that sets a target voltage; and
a controller coupled to the switch of each of the plurality of resistor-switch pairs, the controller sequentially applying turn-on pulses to the switch of the plurality of resistor-switch pairs to produce an output voltage at the voltage output terminal that gradually increases in a step-wise manner until the output voltage corresponds to the target voltage.
8. A DC-DC converter according to claim 7 , wherein a resistance of the resistor of each of the plurality of resistor-switch pairs is the same.
9. A DC-DC converter according to claim 8 , wherein a first turn-on pulse of the switch of one of the plurality of resistor-switch pairs overlaps with a second turn-on pulse of the switch of an other of the plurality of resistor-switch pairs.
10. A DC-DC converter according to claim 7 , wherein a resistance of the resistor of each of the plurality of resistor-switch pairs is different.
11. A DC-DC converter according to claim 10 , wherein a first turn-on pulse of the switch of one of the plurality of resistor-switch pairs does not overlap with a second turn-on pulse of the switch of an other of the plurality of resistor-switch pairs.
12. A DC-DC converter, comprising:
a plurality of transistor-switch pairs connected in parallel between a first junction and a second junction, each of the plurality of transistor-switch pairs including a first transistor and a switch connected in series;
a current source connected to the first junction;
a first resistor connected to the second junction;
a transistor-resistor pair including a second transistor and a second resistor connected in series, the transistor-resistor pair coupled to each of the plurality of transistor-switch pairs to define a plurality of current mirror circuits using the transistor-resistor pair as a reference current generator;
a voltage output terminal connected to the second junction;
a capacitor coupled to the voltage output terminal;
a target voltage generator that sets a target voltage; and
a controller coupled to the switch of each of the plurality of transistor-switch pairs, the controller sequentially applying turn-on pulses to the switch of the plurality of transistor-switch pairs to produce an output voltage at the voltage output terminal that gradually increases in a step-wise manner until the output voltage corresponds to the target voltage.
13. A DC-DC converter according to claim 12 , wherein a first turn-on pulse of the switch of one of the plurality of transistor-switch pairs overlaps with a second turn-on pulse of the switch of an other of the plurality of transistor-switch pairs.