Switching regulator stability control circuit and methodology
View Patent ↗A power stage output node stabilizer may be used to reduce ringing of a power stage output node of a switching DC-DC power converter. The power stage output node stabilizer may be a network of resistors and switches coupling the power stage output node to a higher voltage level and a lower voltage level.
1. A DC-DC switching power converter with a power stage output node stabilizer, comprising:
a high side switch and a low side switch coupled in series between a higher voltage and a lower voltage, with a power stage output node between the high side switch and the low side switch;
an output filter, with a first end and a second end, the first end coupled to the power stage output node;
a plurality of selectably enabled resistive legs coupling the power stage output node and the higher voltage and the lower voltage, each of the resistive legs including a high side portion coupling the power stage output node and the higher voltage and a low side portion coupling the power stage node and the lower voltage, with for each leg, a ratio between a resistance associated with the high side portion and a resistance associated with the low side portion equal to a ratio between a desired voltage to be provided to the load and a difference between the higher voltage and the lower voltage.
2. The DC-DC switching power converter with a power stage output node stabilizer of claim 1 , wherein resistances associated with the high side portions of at least some of the legs differ from each other.
3. The DC-DC switching power converter with a power stage output node stabilizer of claim 1 , wherein resistances associated with the low side portions of at least some of the legs differ from each other.
4. The DC-DC switching power converter with a power stage output node stabilizer of claim 1 , wherein each high side portion of each resistive leg includes a first switch for activating that high side portion, and each low side portion of each resistive leg includes a second switch for activating that low side portion, and further comprising a digital control to activate and deactivate the first switches and the second switches.
5. The DC-DC switching power converter with a power stage output node stabilizer of claim 4 , wherein the digital control is configured to activate the first switches and the second switches only when both the high side switch and the low side switch are open.
6. The DC-DC switching power converter with a power stage output node stabilizer of claim 5 , wherein the control is configured to deactivate the first switches and the second switches over a period of time.
7. The DC-DC switching power converter with a power stage output node stabilizer of claim 4 , wherein the digital control is configured to activate the first switches and the second switches only when both the high side switch and the low side switch are open and the DC-DC switching power converter is in discontinuous conduction mode (DCM).