Integratable efficient switching down converter
View Patent ↗A converter circuit and methods for operating the same. The converter circuit includes a supply voltage, a capacitor, an inductor, and four stacked switching elements. Each switching element is adjustable from a low resistance state to a high resistance state by a control signal. The inductor outputs current to a circuit load. The circuit may be operated in a first mode such that the output is adjustable between the supply voltage and half the supply voltage. Alternatively, in a second mode of operation, the output is adjustable from half the supply voltage to a ground voltage.
1. A voltage converter circuit comprising:
a supply node receiving a supply voltage;
a ground node receiving a ground voltage;
a supply switching element including a first supply terminal, a second supply terminal and a supply control terminal, the first supply terminal electrically connected to the supply node and the supply control terminal receiving a first control signal, the supply control terminal controlling the resistance between the first supply terminal and the second supply terminal;
a top switching element including a first top terminal, a second top terminal and a top control terminal, the first top terminal electrically connected to the second supply terminal, the top control terminal receiving a second control signal, the top control terminal controlling the resistance between the first top terminal and the second top terminal;
a bottom switching element including a first bottom terminal, a second bottom terminal and a bottom control terminal, the first bottom terminal electrically connected to the second top terminal, the bottom control terminal receiving a third control signal, the bottom control terminal controlling the resistance between the first bottom terminal and the second bottom terminal;
a ground switching element including a first ground terminal, a second ground terminal and a ground control terminal, the first ground terminal electrically connected to the second bottom terminal, the second ground terminal electrically connected to the ground node, the ground control terminal receiving a fourth control signal, the ground control terminal controlling the resistance between the first ground terminal and the second ground terminal;
an output node substantially adjustable between the supply voltage and the ground voltage, the voltage at the output node controlled by application of the first, second, third and fourth control signals;
a switching capacitor including a first switching capacitor terminal and a second switching capacitor terminal, the first switching capacitor terminal electrically connected to the second source terminal and the first top terminal, the second switching capacitor terminal electrically connected to the second bottom terminal and the first ground terminal;
an inductor including a first inductor terminal and a second inductor terminal, the first inductor terminal electrically connected to the second top terminal and the first bottom terminal, the second inductor terminal electrically connected to the output node; and
a load capacitor including a first load capacitor terminal and a second load capacitor terminal, the first load capacitor terminal electrically connected to the second inductor terminal and the output node, the second load capacitor terminal connected to the ground node.
2. The voltage converter circuit of claim 1 , further comprising:
wherein the voltage converter is cycled through four sequential phases of operation, the four sequential phases of operation comprising:
a first phase of operation wherein the first, second, third and fourth control signals cause the inductor to drive a drive current to the output node from the switching capacitor;
a second phase of operation wherein the first, second, third and fourth control signals cause the inductor to drive the drive current to the output node from the supply voltage node;
a third phase of operation wherein the first, second, third and fourth control signals cause the switching capacitor and the inductor to be coupled in series circuit such that the drive current passes from the supply node through the switching capacitor and the inductor to the output node and such that the switching capacitor is charged by the drive current; and
a fourth phase of operation wherein the first, second, third and fourth control signals cause the inductor to drive the drive current through to the output voltage node from the supply voltage cause the switching capacitor to be disconnected from the inductor such that the inductor supplies the drive current to the output node due to a magnetic field collapse across the inductor.
3. The voltage converter circuit of claim 2 , wherein:
during the first phase of operation, the supply switching element is off, the top switching element is on, the bottom switching element is off, and the ground switching element is on;
during the second phase of operation, the supply switching element is on, the top switching element is on, the bottom switching element is off, and the ground switching element is off;
during the third phase of operation, the supply switching element is on, the top switching element is off, the bottom switching element is on, and the ground switching element is off; and
during the fourth phase of operation, the supply switching element is on, the top switching element is on, the bottom switching element is off, and the ground switching element is off.
4. The voltage converter circuit of claim 2 , wherein:
during the first phase of operation, the first control signal is set to the supply voltage, the second control signal is set to the ground voltage, the third control signal is set to the ground voltage, and the fourth control signal is set to half the supply voltage;
during the second phase of operation, the first control signal is set to half the supply voltage, and the second control signal is set to the ground voltage, the third control signal is set to the ground voltage, and the fourth control signal is set to the ground voltage;
during the third phase of operation, the first control signal is set to half the supply voltage, the second control signal is set to the supply voltage, the third control signal is set to the supply voltage, and the fourth control signal is set to the ground voltage; and
during the fourth phase of operation, the first control signal is set to half the supply voltage, and the second control signal is set to the ground voltage, the third control signal is set to the ground voltage, and the fourth control signal is set to the ground voltage.
5. The voltage converter circuit of claim 1 , further comprising:
wherein the voltage converter is cycled through four sequential phases of operation, the four sequential phases of operation comprising:
a first phase of operation wherein the first, second, third and fourth control signals cause the switching capacitor and the inductor to be coupled in series circuit such that a drive current passes from the supply node through the switching capacitor and the inductor to the output node and such that the switching capacitor is charged by the drive current;
a second phase of operation wherein the first, second, third and fourth control signals cause the switching capacitor to be disconnected from the inductor such that the inductor supplies the drive current to the output node due to a magnetic field collapse across the inductor;
a third phase of operation wherein the first, second, third and fourth control signals cause the drive current to pass from the switching capacitor through the inductor to the output node; and
a fourth phase of operation wherein the first, second, third and fourth control signals cause the switching capacitor to be disconnected from the inductor such that the inductor supplies the drive current to the output node due to the magnetic field collapse across the inductor.
6. The voltage converter circuit of claim 5 , wherein:
during the first phase of operation, the supply switching element is on, the top switching element is off, the bottom switching element is on, and the ground switching element is off;
during the second phase of operation, the supply switching element is off, the top switching element is off, the bottom switching element is on, and the ground switching element is on;
during the third phase of operation, the supply switching element is off, the top switching element is on, the bottom switching element is off, and the ground switching element is on; and
during the fourth phase of operation, the supply switching element is off, the top switching element is off, the bottom switching element is on, and the ground switching element is on.
7. The voltage converter circuit of claim 5 , wherein:
during the first phase of operation, the first control signal is set to half the supply voltage, the second control signal is set to the supply voltage, the third control signal is set to the supply voltage, and the fourth control signal is set to the ground voltage;
during the second phase of operation, the first control signal is set to the supply voltage, and the second control signal is set to the supply voltage, the third control signal is set to the supply voltage, and the fourth control signal is set to half the supply voltage;
during the third phase of operation, the first control signal is set to the supply voltage, the second control signal is set to the ground voltage, the third control signal is set to the ground voltage, and the fourth control signal is set to half the supply voltage; and
during the fourth phase of operation, the first control signal is set to the supply voltage, and the second control signal is set to the supply voltage, the third control signal is set to the supply voltage, and the fourth control signal is set to half the supply voltage.
8. A method of operating a converter circuit, the converter circuit including a supply voltage, a capacitor and an inductor, the inductor outputting current to a circuit load, the method comprising:
collapsing a magnetic field in the inductor by discharging the capacitor through the inductor for a first duration of time during a first phase of operation;
increasing the magnetic field in the inductor without discharging the capacitor for a second duration of time during a second phase of operation;
charging the capacitor and increasing a magnetic field in the inductor by the supply voltage for a third duration of time during a third phase of operation;
increasing the magnetic field in the inductor without discharging the capacitor for a fourth duration of time during a fourth phase of operation; and
cycling through the first, second, third and fourth phases of operation in sequence.
9. The method of claim 8 , wherein an output voltage at the circuit load is proportional to a ratio of the duty cycle of the first and third phases of operation to the duty cycle of the second and fourth phases of operation.
10. The method of claim 8 , wherein:
the converter circuit includes four stacked switching elements, each switching element adjustable from a low resistance state to a high resistance state by a control signal; and
cycling through the first, second, third and fourth phases of operation in sequence by modifying the control signal at each switching element.
11. A method of operating a converter circuit, the converter circuit including a supply voltage, a capacitor and an inductor, the inductor outputting current to a circuit load, the method comprising:
charging the capacitor and increasing a magnetic field in the inductor by the supply voltage for a first duration of time during a first phase of operation;
collapsing the magnetic field in the inductor without discharging the capacitor for a second duration of time during a second phase of operation;
increasing the magnetic field in the inductor by discharging the capacitor through the inductor for a third duration of time during a third phase of operation;
collapsing the magnetic field in the inductor without discharging the capacitor for a fourth duration of time during a fourth phase of operation; and
cycling through the first, second, third and fourth phases of operation in sequence.
12. The method of claim 11 , wherein an output voltage at the circuit load is proportional to a ratio of the duty cycle of the first and third phases of operation to the duty cycle of the second and fourth phases of operation.
13. The method of claim 11 , wherein:
the converter circuit includes four stacked switching elements, each switching element adjustable from a low resistance state to a high resistance state by a control signal; and
cycling through the first, second, third and fourth phases of operation in sequence by modifying the control signal at each switching element.